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State and Federal Standards for Mobile-Source Emissions (2006)

Chapter: 6 Light-Duty-Vehicle Emissions Standards

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Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
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6
Light-Duty-Vehicle Emissions Standards

On-road light-duty vehicles (LDVs), such as cars, vans, pickup trucks, and sport utility vehicles (SUVs), have the longest history of mobile-source emissions regulation in the United States. Because of their numbers and activity, these vehicles have historically contributed the most to total mobile-source emissions. As discussed in earlier chapters, California’s low-emission-vehicle (LEV) program, introduced in 1990, was an important milestone that helped define today’s California and federal on-road emissions standards. The LEV program is the primary California mobile-source emissions standard adopted by other states. This case-study chapter presents an overview of the LEV program and compares the standard-setting practices of the California Resources Board (CARB) and the U.S. Environmental Protection Agency (EPA), including the practices used to develop the California LEV II and federal Tier 2 standards now in place. The chapter also discusses the practices used by other states in adopting California’s LEV emissions standards.

THE LOW-EMISSION-VEHICLE PROGRAM

The California legislature enacted the California Clean Air Act of 1988, which instructed CARB to “achieve the maximum degree of emission reduction possible from vehicular and other mobile sources” (Cal. Health & Safety Code § 43018(a)). In response to this new legislative mandate, CARB approved an ambitious new rule-making in 1990 to regulate vehicle emissions. The LEV program consisted of several regu-

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

lations to reduce emissions substantially from light- and medium-duty vehicles beginning in model-year 1994. These regulations included stringent new exhaust emissions standards for nonmethane organic gas (NMOG), nitrogen oxides (NOx), carbon monoxide (CO), particulate matter (PM), and formaldehyde.

Rather than requiring every vehicle to meet the same emission standard, the LEV program featured a fleet-based approach, which allows manufacturers the flexibility to meet new emissions standards averaged across their entire product line. This format of the standard, which reduces overall compliance costs, allowed manufacturers a longer development time for vehicles that are the most difficult to control. For LDVs, CARB defined a set of four categories of emissions standards and allowed each manufacturer to certify its vehicle models to any mix of the available standards, provided that the sales-weighted fleet of the manufacturer met the applicable average emission level for that model year. The four available emissions standards in order of increasing stringency were for the transitional low-emission vehicle (TLEV), low-emission vehicle (LEV), ultra-low-emission vehicle (ULEV), and zero-emission vehicle (ZEV). The fleet-average requirement was based on NMOG emissions, and this average became progressively more stringent each model year from 1994 through 2003 (see Table 6-1).

A second feature of the LEV program is that it sought to regulate the vehicle and its fuel as an integrated system. CARB determined that the proposed regulations would encourage vehicle and fuel manufactures to work together to develop LEVs and clean fuels (CARB 1990). In addition to California’s ultra-clean reformulated gasoline, the slate of clean fuels a manufacturer could choose from included methanol, ethanol, liquified petroleum gas (LPG), and compressed natural gas (CNG). Under the regulations, vehicle manufacturers were required to notify CARB 2 years in advance if they intended to certify a LEV vehicle using such an alternative fuel (13 California Code of Regulations [CCR] § 2303). If vehicle manufacturers announced an intention to market a combined total of at least 20,000 vehicles operating on a given clean fuel, then CARB would mandate the availability of such a fuel at California service stations (CARB 1990).

A third feature of the LEV program is that it included a mandate for ZEVs. CARB defined ZEVs as vehicles that have no exhaust or evaporative emissions of any regulated pollutant (CARB 1990). As initially adopted, this ZEV sales mandate required 2% of the passenger cars and light-duty trucks produced and delivered for sale in California by each

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-1 LEV Fleet Average NMOG Standard in Grams per Mile

 

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

PC, LDT, 0-3,750 lb

0.250

0.231

0.225

0.202

0.157

0.113

0.073

0.070

0.068

0.062

LDT, 3,751-5,750 lb

0.320

0.295

0.287

0.260

0.205

0.150

0.099

0.098

0.095

0.093

Abbreviations: PC, passenger car; LDT, light-duty truck.

Source: CARB 1998a.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

large-volume1 manufacturer to be ZEVs in the 1998 model year. This requirement increased to 5% in 2001 and 10% in 2003. Although the ZEV mandate was technologically neutral in that it did not specify the technology required to meet the ZEV standard, CARB noted that, at the time, only battery-powered electric vehicles were candidates to be ZEVs. CARB also stated that other technologies (such as fuel cells) could be developed in the future to meet the standard (CARB 1990).

The ZEV mandate was a notable departure of the LEV program from the flexibility of allowing manufacturers to choose how to comply with the NMOG fleet-average requirement. Nevertheless, CARB concluded that such a mandate was necessary because a “significant penetration of ZEVs is crucial to long-term attainment of the ambient standards in the South Coast, and there is no assurance that ZEVs will be developed without the limited, measured ZEV sales requirements in the regulations” (CARB 1991). An important aspect of a ZEV is the additional emissions benefits that are gained because there is no deterioration of emissions-control equipment over time. Although the primary objective of the ZEV mandate was to reduce vehicle emissions, CARB identified secondary benefits, including the investment by industry and communities in batteries and infrastructure for ZEVs (CARB 1991), the potential to “contribute to national and state energy diversity and security,” and the potential “to revitalize California’s economy through job creation and growth in an emerging industry” (CARB 1994a). (Although ZEVs have no emissions, electricity produced from fossil fuels to charge ZEVs results in air pollutant emissions, and these emissions, either inside or outside of California, affect air quality.)

The LEV program included a credit program to give manufacturers additional flexibility to meet the standards. Manufacturers could earn NMOG fleet-average credits in any model year by achieving a sales-weighted fleet-average emissions level lower than the applicable fleet-average standard for that model year. The credits could be sold to other manufacturers or applied to help the manufacturer achieve compliance in future model years, although the credits are substantially discounted with time. A second credit program pertaining to the ZEV mandate allowed manufacturers to obtain credits for complying with the ZEV mandate

1  

Generally, small-volume manufacturers in California sell fewer than 4,500 vehicles and engines per year, intermediate-volume manufacturers sell 4,501-60,000 per year, and large-volume manufacturers sell the remainder of the vehicles sold in California. See Title 13, California Code of Regulations, Section 1900 for exact definitions.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

early. Like the NMOG credits, ZEV credits could be banked internally for future use or sold to other manufacturers. CARB initially rejected suggestions that hybrid electric vehicles (HEVs) should be eligible for partial credits under the ZEV mandate (CARB 1991) but provided some additional NMOG credits for HEVs that achieved certain performance goals.

A final feature of the California LEV program is its built-in process for periodic review of the program and revision, if necessary. Because of the far-reaching and long-term nature of the LEV program, CARB committed to a biennial review of its LEV program to monitor manufacturer compliance plans and to identify any problems with the feasibility of its demanding program. In response to this mandate, CARB has produced several reviews (CARB 1994b, 2000a,b).

The Zero-Emission-Vehicle Mandate

Although the overall LEV program was widely considered successful at reducing vehicle emissions and promoting advanced emissions-control technologies, the ZEV experiment has fallen short of its original expectations to promote the widespread use of electric vehicles. This requirement, which was premised on the availability of electric vehicles by model-year 1998, is an example of misjudgment by CARB that the required and expected ZEV technology would be feasible. CARB has revised its original ZEV mandate with four sets of successive revisions, resulting in a much diluted requirement today that no longer emphasizes electric vehicles and affecting CARB’s credibility in the program itself. General Motors invested an estimated $1 billion over several years to develop ZEVs, which now do not appear to be headed for widespread use in society (GM 2005). To put this number in context, General Motors spent approximately 6.5 billion on total research and development in 2004 (Hira and Goldstein 2005).

The problems of the ZEV mandate are reflected in CARB’s shifting estimates on the feasibility and costs of using electric vehicles. CARB initially thought in 1990 that, by 2000, electric vehicles would be comparable in cost to conventional vehicles plus an estimated $1,350 per vehicle cost for the batteries (CARB 1990). In 1994, CARB increased its estimate of the incremental additional costs of an electric vehicle to $5,000-$10,000 more than a conventional gasoline-fueled vehicle (CARB 1994b). In its 2000 review of the ZEV mandate, CARB staff es-

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

timated that the incremental cost of a freeway-capable ZEV would be approximately $20,000 more than a conventional vehicle (CARB 2000a).

The biennial reviews of the LEV program that CARB promised in adopting the program have largely focused on the ZEV mandate from the second biennial review in 1994. In the 1994 review, vehicle manufacturers emphasized concerns about the feasibility of the ZEV mandate and requested that CARB relax the ZEV mandate to permit ZEV credits for such vehicles as HEVs with extremely low emissions (CARB 1994b). CARB concluded at the end of a 2-day public hearing on the subject that the ZEV mandate was an important part of the LEV program, and no revisions were necessary at that time. CARB also instructed the staff to reconsider the role of HEVs within the framework of the ZEV mandate.

In preparation for the biennial review in 1996, CARB established an independent panel of experts to evaluate the readiness of electric vehicle battery technology to meet the ZEV mandate in the 1998 model year. The expert panel report concluded that even under “a complete success scenario,” with no delays or unforeseen obstacles, “electric vehicles with commercial-production advanced batteries could become available in 2000 or 2001” at the earliest (Kalhammer et al. 1995). The panel also found that lead-acid batteries limited electric vehicles using such batteries to a small “niche” market. Based on the basis of the expert panel’s recommendations, CARB voted to repeal the California ZEV mandate for model-years 1998 through 2002 to provide “time necessary for advanced technology battery developers to achieve commercialization” (CARB 1996).

In 1996, CARB also negotiated separate memoranda of agreement (MOA) with each of the seven manufacturers initially subject to the ZEV mandate. The MOAs required the manufacturers to place over 1,800 advanced-battery electric vehicles into operation in demonstration programs in California between 1998 and 2000. Manufacturers were also required to offset the emissions benefits that would have been achieved by the ZEV mandate from 1998 through 2002 by agreeing to the nationwide introduction of LEVs several years before such vehicles could be mandated under the federal CAA (CAA). (This manufacturer obligation was implemented through the National Low Emission Vehicle [NLEV] Program described below in the section Influences of the LEV Program on National Mobile-Source Emissions Standards.) The MOAs also obligated CARB to work with state and local governments to help develop ZEV infrastructure and remove other barriers to ZEV implementation.

Following the biennial review in 1998, CARB further relaxed the 2003 mandate in its LEV II rule-making (see below) by allowing ZEV

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

credits to be earned by vehicles with near-zero emissions, referred to as partial ZEVs (PZEVs). Intermediate-volume manufacturers were permitted to meet their ZEV mandate requirements entirely with PZEV credits, and large-volume manufacturers were permitted to meet up to 60% of their ZEV mandate requirements with PZEV credits. A manufacturer could obtain from 0.2 to 1.0 ZEV credit for each PZEV sold, depending on the vehicle’s characteristics.

In the 2000 biennial review, CARB again appointed an advisory panel of battery experts to evaluate the availability and cost of electric vehicle batteries. The expert panel concluded that advanced technology batteries with reasonable cost and performance characteristics would not be available in time to meet the 2003 mandate. The panel found that the most promising advanced battery was a nickel-metal hydride battery but that production of such batteries in quantities to meet the 2003 ZEV mandate would be $9,500 to $13,000 per battery, many thousands of dollars above the cost that could be commercially viable. Moreover, such batteries would produce a range of only 70-100 miles, which was below the expectations of most potential customers. The battery panel concurred with the manufacturers “that EVs with the battery costs and limitations anticipated for the foreseeable future will find only very limited markets, well below the numbers of vehicles called for by the ZEV regulatory provisions beginning in 2003” (Anderman et al. 2000).

Moreover, as part of its analysis for the 2000 biennial review, CARB determined that the PZEV standard would be “extremely challenging” for many vehicles to meet and that most manufacturers would not be capable of complying with the ZEV mandate in 2003 by using PZEV credits (CARB 2000a). CARB also recognized that in the initial years of the ZEV mandate, manufacturers would not be able to recover the full cost of ZEV production by using only price. Unless the state and local air districts could provide the substantial funds that would be needed to subsidize these vehicles, manufacturers would have to either absorb the economic losses internally or pass on the costs to purchasers of other vehicles (CARB 2000a).

Despite those findings, CARB voted unanimously at its September 2000 meeting to affirm the mandate as an essential component of California’s long-term air quality strategy and to retain the basic ZEV requirements (CARB 2000c). CARB nevertheless instructed staff to develop some regulatory fine-tuning to address the challenges associated with the successful long-term implementation of the ZEV program. A month later, CARB staff expressed concern that the biennial review process and resulting revisions to the ZEV mandate “has interfered with

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

the orderly growth of the ZEV market, because of the uncertainty it introduces into planning and implementation activities on the part of manufacturers, government agencies, and other parties” (CARB 2000d).2

At its next meeting to review the ZEV mandate in January 2001, CARB further relaxed the ZEV mandate. The 2001 amendment allowed large-volume manufacturers to meet another 20% of their ZEV obligation with partial credits from advanced-technology vehicles known as AT-PZEVs. AT-PZEVs include gasoline HEVs that meet specific criteria. Several other refinements and additions to the ZEV credit structure were enacted in this same rule-making.

In June 2002, a California federal judge issued a preliminary injunction against implementation of the ZEV mandate in a lawsuit brought by vehicle manufacturers and dealers. The lawsuit contended that the ZEV mandate as modified in 2001 was preempted by the federal fuel economy standards (Central Valley Chrysler-Plymouth, Inc., et al. v. Witherspoon, Case No. CIV F-02-05017 REC SMS [E.D. Cal.]). As part of a settlement of that litigation in April 2003, CARB amended the ZEV mandate to provide an Alternative Compliance Plan (ACP) option in which large-volume manufacturers could meet much of their ZEV requirement by producing their sales-weighted share of approximately 250 fuel-cell vehicles by 2008. The required number of fuel-cell vehicles would increase to 2,500 from 2009 to 2011, 25,000 from 2012 to 2014, and 50,000 from 2015 to 2017.

CARB recognized that other states might adopt the California ZEV program and ACP under section 177 of the federal 1990 CAA and might require production of their own fuel-cell vehicles, which would require manufacturers to produce more fuel-cell vehicles (CARB 2004b). To address that problem, CARB allowed a fuel-cell vehicle placed in any state that had adopted the California ZEV program to count toward California’s ZEV requirement and conversely allowed any fuel-cell vehicle placed in California to count toward another state’s ZEV requirement. The start date for those requirements was delayed from 2003 to 2005.

The 2003 amendments to the ZEV mandate are the most important yet, and they strongly signaled CARB’s recognition that electric vehicles are not a promising technology to achieve the zero-emission goal to which the agency still strongly adheres (CARB 2004b). As part of this

2  

Public Workshop to Discuss Issues Related to the Zero Emission Vehicle Regulations: Agenda and Background Material, Oct. 16, 2000.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

rule-making, CARB undertook another evaluation of the feasibility of battery electric vehicles and concluded that “the cost and performance characteristics of advanced batteries have not meaningfully changed” since the 2000 battery panel report, and that “even at substantially increased production levels full function EVs would not be cost competitive with conventional vehicles, and that there does not appear to be a viable path that will result in commercialization for general markets.” (CARB 2004b). In contrast, “manufacturers appear to believe there is a business case for fuel cell development. Staff concurs that the technology shows great promise and fully expects fuel cell development to proceed to commercialization” (CARB 2004b). CARB estimated that vehicle manufacturers had already invested “several billion dollars to date in developing fuel cell technology and have publicly stated plans to continue heavy investment in the next decade” (CARB 2004b). CARB concluded that despite this effort, “fuel-cell ZEVs are clearly not ready for volume production” at this time (CARB 2004b). In the meantime, there have been “rapid advances” in HEVs and similar extremely clean vehicles certified according to the PZEV and AT-PZEV standards (CARB 2004b). “Under these circumstances, CARB has concluded that the best course of action is to take full advantage of the near-term possibilities afforded by PZEVs and AT-PZEVs, and adopt a stepwise approach toward pure ZEV commercialization that takes into account the desire of vehicle manufacturers to devote their entire ‘gold’ vehicle [pure ZEVs] focus to fuel cell ZEVs” (CARB 2004b).

Despite the numerous revisions and delays in implementing the ZEV mandate, CARB claims that its ZEV mandate has been “instrumental in promoting battery, fuel cell, component and vehicle research and development” (CARB 2000b). A study commissioned by CARB found that the California ZEV mandate had produced important secondary benefits in such categories as new economic development in California, advanced vehicle development, vehicle emissions reductions outside of California, and nonelectric vehicle applications of advanced batteries (Burke et al. 2000). Similarly, the 2000 CARB battery panel (Anderman et al. 2000) found that the battery research motivated by the California ZEV mandate undoubtedly benefited the development of better batteries for use in HEVs. These batteries have much less stringent technical requirements than do totally electric vehicle batteries. Although the ZEV mandate has had some indirect beneficial impacts in motivating research into hybrid electric and fuel-cell vehicles, these benefits cannot obscure the fact that the ZEV mandate forced manufacturers to devote consider-

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

able resources to develop electric vehicles, which appear at the present to be economically unviable. CARB’s chairman was quoted in the press, “We have put a lot of faith in battery electric vehicles to meet the [zero-emission vehicle] mandate, but in spite of significant efforts batteries have inherent limitations. We’re not giving up on the goal of the zero-emission vehicle, but we have to be realistic. No matter how you cut it, it is disappointing” (Polakovic 2002).

This history of the LEV and ZEV demonstrates the benefits of using California as a laboratory to experiment with aggressive, high-risk strategies. The technology-forcing requirements that CARB imposes can result in major breakthroughs in emissions controls. When CARB adopted its LEV standards, vehicle manufacturers claimed that the standards were not technologically feasible within the available lead time (CARB 1991). Under the pressure of the LEV regulations, vehicle manufacturers were able to exceed expectations in reducing emissions from gasoline-powered vehicles to near-zero levels. As discussed below, the success of the LEV program in California benefited emissions-control strategies across the nation and was primarily responsible for making the new federal standards for model-year 2004 more stringent than they otherwise would have been.

An inevitable consequence of a high-risk strategy is the likelihood that some policies will fail, and the electric vehicles envisioned under the California ZEV mandate appear to have failed. Manufacturers had a good record of complying with performance-based emissions standards. In contrast, the ZEV mandate was a technology-specific regulation in its early stages and proved to be too challenging. Although the costs and disruptions of the electric vehicle mandate were substantial, they were limited to a relatively small segment of the national market. The results of the CARB ZEV experiment support the idea of having one state (California) serve as a laboratory for experimentation in emissions control.

Impacts of LEV Program on LDV Emissions-Control Technologies

The LEV program provides a good example of California’s role as a laboratory for innovation and technology to reduce mobile-source emissions. The primary success of the LEV program has been in achieving near-zero levels of tailpipe emissions from gasoline-fueled vehicles, exceeding the expectations of experts in both industry and government. One of the reasons that CARB initiated the low-emission vehicle/clean

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

fuels program was that it thought that alternative fuels were likely to be needed to get vehicle emissions down to the ULEV standard or lower. In fact, because of the combination of technology-forcing and flexibility in the LEV program, manufacturers have achieved much greater progress in reducing emissions from conventional vehicles than was believed possible in 1990. In the words of CARB’s chairman, Dr. Alan Lloyd, under the LEV program, “We’ve seen the near impossible accomplished with gasoline vehicles: zero evaporative emissions, exceedingly clean exhaust—cleaner, in some cases, than the outside air entering the cabin for ventilation purposes and emission control systems that are twice as durable as their conventional forebearers, forecasted to last an astonishing 150,000 miles” (CARB 2003b).

The technologies that enabled this enormous progress are a combination of improved catalyst technology, better on-board diagnostic systems, and cleaner reformulated gasoline (Ehlmann and Wolff 2005). For example, in adopting the LEV program, CARB expected that manufacturers would comply with the LEV and ULEV standards primarily by installing electrically heated catalysts. Electrically heated catalysts reduce cold-start emissions, which account for a large majority of the remaining emissions from modern motor vehicles (CARB 1991). However, manufacturers achieved the ULEV standard and beyond in gasoline-fueled vehicles through improved materials that allowed the catalyst to be more heat resistant, resulting in faster warm-up by allowing them to be placed much closer to the engine. The elimination of the electrically heated catalysts to comply with the LEV standards reduced the cost and simplified integration into the vehicle design.

Indeed, compliance with California standards creates its own subset of automobile engineering research featured in such journals as Topics in Catalysts and Applied Catalysis and publications of the Society for Automotive Engineers. Examples of such research for the LEV program are Summers et al. (1993), Smaling et al. (1996), and Truex (1998). More recent examples include technologies to comply with aspects of the LEV II program, such as McKinnon et al. (1999), Heck and Farrauto (2001), and Kim et al. (2001).

The impact of California standards is characterized several times in this report as either a success due to CARB’s role in looking at fuels and engines as an integrated unit or as a failure due to its inability to bring about widespread use of electric vehicle technology. In reality, it is too simplistic to characterize the outcomes as simple successes and failures. For example, the impact of the ZEV on the introduction of popular hy-

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

brid technologies is not straightforward. The pursuit of many low-emissions technologies, including hybrid technologies, came in response to CARB standards for lower and zero emissions vehicles. However, CARB initially did not favor the HEVs as a part of the ZEV mandate. Sorting out the full relationship between the ZEV mandate and HEVs requires an in-depth understanding of many factors, including strategic business strategies, beyond the purview of this committee.

Influence of the LEV Program on National Mobile-Source Emissions Standards

Many northeastern states actively pursued adoption of California’s LEV program in the 1990s to achieve emissions reductions that would help to meet their air quality goals. Thirteen northeastern states that were the members of the Ozone Transport Commission (OTC), created by the 1990 CAA amendments, pledged in October 1991 to adopt the California LEV standards. Massachusetts, New York, and Maine adopted LEV emissions standards between 1991 and 1993. As a result of those state efforts, manufacturers proposed in the fall of 1993 that they would voluntarily provide low-emitting cars that exceed the federal standards to the 49 non-California states in return for the northeastern states abandoning the California LEV program, particularly its ZEV mandate (Jolish 1999). This initial proposal resulted in over 4 years of active negotiations among the states, vehicle manufacturers, and other interested parties under the active supervision of EPA. The resulting NLEV program could provide stricter standards before EPA since the 1990 CAA amendments specified that the next set of federal emissions standards (Tier 2), if necessary, were not to begin until 2004 model-year vehicles.

In October 1995, EPA published a public notice of its plans to implement a voluntary NLEV program (60 Fed. Reg. 52733 [1995]). EPA determined that the NLEV program would result in equivalent or better emissions reductions in the Northeast Ozone Transport Region than would be achieved by having state-by-state adoption of the California LEV program (including the ZEV mandate) (60 Fed. Reg. 52737 [1995]). EPA also concluded that NLEV would reduce states’ costs of improving air quality by avoiding separate, duplicative state programs (60 Fed. Reg. 52736 [1995]). It took another 2 years until the NLEV program was finalized by EPA in early 1998 (63 Fed. Reg. 926 [1998]). Under this voluntary program, vehicle manufacturers would provide low-

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

emitting vehicles to all northeastern states beginning in 1999 and to all 49 non-California states beginning in 2001, and the states would forego implementation of the California LEV program. The program would remain in effect until the 2006 model year. Four states (Massachusetts, New York, Maine, and Vermont) refused to adopt the NLEV program because they were unwilling to forego the ZEV mandate and the California standards for medium-duty vehicles, which were not included in the NLEV program. Despite the four holdout states, EPA calculated that the NLEV program would achieve greater emissions reduction in the Northeast region than either regionwide adoption of California LEV by the OTC or state-by-state adoption of the LEV program. The greater emissions reduction would be largely due to the reduced emissions from permanent or short-term migration of cars into the Northeast from other parts of the nation and to the implementation the NLEV program at an earlier time than would be possible for adoption of the LEV program in all northeastern states. EPA described the NLEV program as “cleaner, smarter, cheaper” than the California LEV program for reducing motor vehicle pollution in the Northeast states (62 Fed. Reg. 31192 [1997]).

The NLEV program provides two major lessons. First, the technology-forcing nature of California standards can benefit not only California but also the rest of the country. The NLEV program, which resulted in substantial reductions of vehicle emissions across the nation beyond what was required under the 1990 CAA amendments, could exist only because of California’s leadership in forcing stricter emissions controls and the rights of other states to adopt those standards under section 177 of the federal CAA. Without the emissions-control technology resulting from the California program and the legal authority of other states to adopt the program, vehicle manufacturers would have had no incentive to enter into the NLEV program. The second lesson of NLEV is that vehicle manufacturers are prepared to expend substantial resources to avoid a patchwork of state emissions requirements. The NLEV commitment by manufacturers demonstrates with actions rather than words that two standards do impose a substantial burden on manufacturers.

CURRENT CALIFORNIA AND FEDERAL EMISSIONS STANDARDS

In 1998, CARB proposed a rule-making for LEV II emissions standards to take effect with model-year 2004 vehicles. The technologies

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

used by auto manufacturers to meet the original LEV emissions standards, particularly catalysts, created the potential for emissions control beyond the LEV standards. The LEV II program kept the key features of the LEV program and introduced several new features. The LEV II program included a restructuring of the light-duty-truck (LDT) classifications, and many pickup trucks and SUVs are now subject to the same emissions standards as passenger cars. Since the start of the LEV program, the fraction of pickup trucks and SUVs in the fleet had increased substantially (see discussion in Chapter 3). Many of those vehicles were previously classified as LDT (3,751 to 5,750 lb loaded vehicle weight [LVW3]) or medium-duty vehicle (MDV) (various categories from 3,751 to 14,000 lb test weight [TW]) under the LEV program and were subject to less stringent emissions standards than passenger cars and the smallest LDTs (those with a LVW of 3,750 lb or less). In the LEV II program, the LDT 2 category includes trucks weighing 3,751 to 8,500 lb GVW, which includes many of the models of pick-ups, SUVs, and vans that are now commonly used as passenger vehicles. All passenger cars and LDTs less than 8,500 lb GVW are subject to the same emissions standards under the LEV II program.

In addition to subjecting more LDTs to the most stringent standards, the LEV II program certified each vehicle according to standards at 50,000 and 120,000 miles. The LEV II program introduced another new emissions class called super-ultra-low emission vehicle (SULEV) and removed the transitional LEV (TLEV) category. SULEV emissions levels are even lower than ULEV levels and have no intermediate life certification. Furthermore, the permissible level of NOx emissions in the LEV and ULEV certification categories at 50,000 miles was reduced from 0.2 to 0.05 grams/mile (g/mi). Under LEV II, the NMOG fleet average will continue to decline yearly from 0.062 g/mi in 2003 to 0.035 g/mi in 2010 for passenger cars and LDT 1 and from 0.085 g/mi in 2004 to 0.043 g/mi in 2010 for LDT 2. (These and further specifications for the LEV II program are discussed in CARB [1998a, 1999].)

The federal 1990 CAA amendments included new national LDV emissions standards to begin with model-year 1994, known as Tier 1 standards. Although these levels were more stringent than the pre-1990

3  

Vehicle weight is defined a number of ways and is different for different vehicle classes. Loaded vehicle weight (LVW) is the curb weight plus 300 lb. Gross-vehicle weight (GVW) is the curb weight plus a full payload. Test weight (TW) is used for CARB’s medium-duty vehicles and is the average of a vehicle’s curb weight and GVW.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

emissions standards, Tier 1 standards did not include the features of California’s LEV program—for example, flexibility of vehicle classes, fuel requirements, and a ZEV sales mandate. As discussed above, NLEV standards based on California’s LEV program replaced Tier 1 standards in 1998 and aligned federal and California vehicle emissions standards, although the NLEV did not include a ZEV component. The CAA, however, specified that Tier 2 emissions standards for LDVs and MDVs were to begin with model-year 2004. The CAA directed EPA to assess the need for Tier 2 standards and to adjust the levels of the standards in light of air quality needs, technical feasibility, and cost-effectiveness. Logically, EPA set Tier 2 standards at levels that were commensurate with the great advances in emissions-control technologies introduced in the 1990s, in part, as a result of the LEV program. Tier 2 also incorporated some features of the LEV program, such as the flexibility of a fleetwide-average standard, the ability for manufacturers to certify according to different emissions classes (called bins), and the reliance on low-sulfur fuel to achieve the prescribed standard. Because of concerns about the increased sensitivity of the new-technology vehicles to sulfur poisoning, the Tier 2 standards required refiners to meet an average sulfur concentration of 30 ppm beginning January 1, 2006. Low-sulfur gasoline was introduced in California in the 1990s. Another important similarity between Tier 2 and LEV II is that LDTs up to 8,500 lb GVW are subject to the same stringent emissions standards as passenger cars after a phase-in period. In contrast to LEV II, Tier 2 includes a fleet-average NOx emissions standard, which does not decline with time after the program is phased in. Table 6-2 summarizes the features of LEV II and Tier 2.

Emissions reductions over the fleet of vehicles subject to Tier 2 and LEV II programs in coming years will depend on many factors and assumptions about the future mix of vehicles in each fleet. Given the greater than 95% emissions reductions achieved by both programs, California and federally certified passenger vehicles are considered by some to produce “near-zero” emissions of NOx, volatile organic compounds (VOCs), and carbon monoxide (CO) (Ehlmann and Wolff 2005). The committee heard arguments that the two programs are now practically equivalent in terms of emissions benefits (Dana 2004). As discussed in later sections, however, some parties consider the difference in emissions between the programs to be appreciable, especially due to the ZEV mandate (NESCAUM 2003). Figure 6-1 compares the California and EPA tailpipe standards by model year in grams per mile. These projected rates were provided by CARB and are based on the assumption that manufac-

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-2 Comparison of the Features of the LEV II and Tier 2 Programs

Feature

LEV II

Tier 2

Regulated vehicle types

PC, all weights

LDT1, 0-3,750 lb GVW

LDT2, 3,751-8,500 lb GVW

MDV, 8,500-10,000 lb GVW

MDV, 10,000-14,000 lb GVW

LDV, 0-8,500 lb

LLDT, 0-6,000 lb GVW

HLDT, 6,000-8,500 lb GVW

MDPV, 8,500-10,000 lb GVW

Certification categories

ZEV, AT-PZEV, PZEV, SULEV, ULEV, LEV (see certification levels in Table 6-3)

Bin 1 through Bin 11; Bin 10 and 11 removed after phase-in; Bin 11 for MDPV only (see certification levels in Table 6-4)

Phase-in

For PC, LDT1 and LDT2 at least 25%, 50%, 75%, and 100% resp. in 2004, 2005, 2006, 2007 must be certified to LEV II standards. Alternate phase-in is possible if equivalent NOx emissions reductions are achieved.

For LDV/LLDT, at least 25%, 50%, 75%, 100% in 2004, 2005, 2006, 2007 respectively, must be Tier 2; for HLDT/MDPV, at least 50% in 2008 and 100% in 2009 must be Tier 2

Fleet-average exhaust emissions requirements (corporate average)

Based on NMOG emissions (all values in g/mile NMOG)

Based on NOx emissions

 

Model Year

PC/LDT1

LDT2

During phase-in:

0.30 g/mi for all non-Tier 2 LDV/LLDT

0. 20 g/mi all non-Tier 2 HLDT/MDPV

0.07 g/mi for all Tier 2 vehicles

After phase-in:

0.07 g/mi for all LDV/LLDT after 2007 for all HLDT/MDPV after 2009

2004

0.053 g/mi

0.085 g/mi

2005

0.049 g/mi

0.076 g/mi

2006

0.046 g/mi

0.062 g/mi

2007

0.043 g/mi

0.055 g/mi

2008

0.040 g/mi

0.050 g/mi

2009

0.038 g/mi

0.047 g/mi

2010+

0.035 g/mi

0.043 g/mi

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

Certification age

Intermediate life, 50, 000 mi; full useful life, 120,000 mi; optional, 150,000 mi for credits toward NMOG fleet average

Intermediate life, 50, 000 mi; full useful life, 120,000 mi

Sales mandate

ZEV (with PZEV, partial credits and ACP plans)

No sales mandate

Fuel requirements

Sulfur at 15 ppm

Sulfur at average 30 ppm by 2006

Abbreviations: ZEV, zero-emission vehicle; PZEV, partial-ZEV; AT-PZEV, advanced-technology-PZEV; LEV, low-emission vehicle; SULEV, super-ultra-LEV; ULEV, ultra-LEV; PC, passenger car; LDT, light-duty truck; LLDT, light-LDT; HLDT, heavy-LDT; MDV, medium-duty vehicle; LDV, light-duty vehicle; MDPV, medium-duty passenger vehicle; ACP, alternative compliance plan.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

FIGURE 6-1 Comparison of California and federal emissions standards (NOx + NMOG) in g/mile estimated by CARB. Only vehicles less than 8,500 lb GVW are included. Source: Adapted from CARB 2005e.

TABLE 6-3 LEV II Full Useful Life (120,000 mi) Exhaust Mass Emissions Standards in grams/mile

Type

Category

NOx

NMOG

CO

HCHO

PM

PC and LDT1 and LDT2

SULEVa

0.02

0.010

1.0

0.004

0.01

 

ULEV

0.07

0.055

2.1

0.011

0.01

 

LEV

0.07

0.090

4.2

0.018

0.01

 

LEVb

0.10

0.090

4.2

0.018

0.01

MDV 8,500-10,000

SULEV

0.1

0.100

3.2

0.008

0.06

 

ULEV

0.2

0.143

6.4

0.016

0.06

 

LEV

0.2

0.195

6.4

0.032

0.12

MDV 10,000-14,000

SULEV

0.2

0.117

3.7

0.010

0.06

 

ULEV

0.4

0.167

7.3

0.021

0.06

 

LEV

0.4

0.230

7.3

0.040

0.12

aPZEV vehicles have the same exhaust standards as SULEV, but have more stringent evaporative and warranty requirements.

bUp to 4% of a manufacturers LDT2 may certify to this higher NOx LEV category.

Source: CARB 1998a.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-4 Tier 2 and Interim Non-tier 2 Full Useful Life (120,000 mi) Exhaust Mass Emission Standards in grams/mile

Bin No.

NOx

NMOG

CO

HCHO

PM

1

0.00

0.000

0.0

0.000

0.00

2

0.02

0.010

2.1

0.004

0.01

3

0.03

0.055

2.1

0.011

0.01

4

0.04

0.070

2.1

0.011

0.01

5

0.07

0.090

4.2

0.018

0.01

6

0.10

0.090

4.2

0.018

0.01

7

0.15

0.090

4.2

0.018

0.02

8

0.20

0.125/0.156b,f

4.2

0.018

0.02

9a

0.3

0.090/0.180b,e

4.2

0.018

0.06

10a

0.6

0.156/0.230b,d

4.2/6.4

0.018/0.027

0.08

11a,c

0.9

0.280

7.3

0.032

0.12

aThis bin and its corresponding intermediate life bin are deleted at end of 2006 model year (end of 2008 model year for HLDTs and MDPVs).

bHigher NMOG, CO or HCHO values apply for HLDTs and MDPVs only.

cThis bin is only for MDPVs

dOptional NMOG standard of 0.280 g/mi applies for qualifying LDT4s and qualifying MDPVs only.

eOptional NMOG standard of 0.130 g/mi applies for qualifying LDT2s only.

fHigher NMOG standard deleted at end of 2008 model year.

Source: 65 Fed. Reg. 6855 (2000).

turers will produce larger numbers of near-zero-emission vehicles to satisfy the ACP option to meet their ZEV mandates (CARB 2005e). The figure does not show the difference in future emissions expected in regions with LEV II vehicles compared with regions with Tier 2 vehicles.

PROCESS OF SETTING STANDARDS: LEV II VS TIER 2

The charge to the committee called for an evaluation of the scientific and technical practices used by CARB in setting California emissions standards and for a comparison of its practices with those used by EPA. The comparison of the practices used by CARB and EPA in setting their LEV II and Tier 2 standards, respectively, is an appropriate case study because both processes required extensive regulatory assessments completed relatively recently. LEV II and Tier 2 are the current California and federal LDV and LDT emissions standards and both came into

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

effect with model-year 2004. The committee compared standards for on-road vehicles primarily in terms of two analysis documents: “The Staff Paper—Initial Statement of Reasons” (the staff paper) for LEV II (CARB 1998a) and the “Regulatory Impact Analysis” (RIA) for Tier 2 (EPA 1999A), although a large number of other documents were used for both analyses. Practices used by CARB and EPA to set emissions standards are categorized as four assessments: the need for new standards, technical feasibility, emissions and air quality impacts, and economic impacts.

The Need for New Mobile-Source Emissions Standards

The ultimate objective of regulating any emissions source is the protection of public health and welfare. In the United States, one way that is accomplished is by setting NAAQS for criteria pollutants, which have traditionally been the main focus of mobile-source regulation. California established its own ambient air quality standards (AAQS) for criteria pollutants. As shown in Table 2-1 in Chapter 2, California’s AAQS are more stringent than the federal NAAQS although the state does not have AAQS attainment deadlines. Attainment of the NAAQS, for ground-level ozone has in particular been the impetus for regulating mobile-source emissions in recent decades. CARB, as a state agency delegated the responsibility to attain the NAAQS in California, is required by the federal CAA to develop a state implementation plan (SIP) (see discussion in Chapter 3). One element of the SIP is to identify and prescribe source-specific emissions reductions required in each area to attain the NAAQS. EPA sets national emissions standards by authority of the CAA with the goal of progressively attaining the NAAQS nationwide; however, the level of emissions reductions is not tied directly to NAAQS attainment of specific airsheds. The difference is evident in the agencies’ assessment of the need for the LEV II and Tier 2 regulations.

CARB submitted a SIP for the South Coast Air Quality Management District (AQMD) to EPA in 1994 with measures to reach attainment for ground-level ozone by 2010. Among other measures, the SIP included a measure called M2 for reducing mobile-source NOx plus NMHC4 by 25 tons per day (tpd) in the South Coast (CARB 1994c).

4  

Various terms to denote hydrocarbons are used in different regulatory documents. The differences are explained in Appendix A.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

Even with M2 reductions and other reductions from all identified sources, CARB determined that more emissions reductions were needed to meet the goals of the SIP. An additional amount, the so-called black-box, required an additional NOx and NMHC of 75 tpd from to-be-determined sources.5 The need for the black-box emissions reductions provides evidence of the extent to which control strategies must be pushed to meet air quality goals in the South Coast region. CARB states that “the primary objective of the [LEV II] rulemaking is to implement Measure M2 of the 1994 California SIP for ozone, and to achieve as much additional reactive organic gases (ROG) plus NOx emissions reductions as are technologically feasible and cost-effective, to be counted against the SIP’s additional 75 tpd ROG plus NOx emission reduction target—the so-called black-box” (CARB 1999).

California’s need for stricter emissions standards was based on the emissions reductions needed in the South Coast to attain the 1-hr-average NAAQS for ozone; however, stricter LDV standards were also a means to improve air quality in other parts of the state for ozone, particulate matter (PM), and hazardous air pollutants (HAPs). The assessment of the need for emissions reductions, and thus the need for stricter standards, was performed by the South Coast AQMD as part of the modeling analysis for the SIP. The analysis includes estimation of present and future emissions inventories, including mobile sources. The analysis also includes photochemical grid modeling to determine the expected reductions in ground-level ozone concentrations that result from precursor emissions reductions.

EPA has general authority to prescribe vehicle emissions standards that are not prescribed or limited in CAA section 202(a). As a result of the 1990 amendments, CAA explicitly lists the numerical values of the Tier 1 exhaust emissions standards for LDVs and LDTs, which began with model-year 1994 vehicles. The CAA further directed EPA to submit a report to Congress in 1997 on the need, feasibility, and cost-effectiveness of new vehicle standards for 2004-2006. If the study found

5  

The use of unspecified, or black-box, emissions reductions in SIPs was included in Section 182(e)(5) of the federal CAA amendments of 1990. It is only available to areas classified as “extreme” nonattainment for ozone, based on the severity of measured ozone concentrations. To date, the San Joaquin Valley and the South Coast air basins in California are the only areas of the nation to be classified extreme by EPA. It appears that the black-box measures continue to apply in meeting the 8-hr ozone NAAQS in the areas that were classified extreme nonattainment for the 1-hr ozone NAAQS.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

that standards were necessary, feasible, and cost-effective, EPA was then directed to set emissions standards via a rule-making. CAA section 202(i) included numerical values for Tier 2 standards as an alternative for EPA to consider if more stringent standards were deemed necessary, feasible, and cost-effective. The study, known as the “Tier 2 Report to Congress,” concluded that there would be an air quality need for emissions reductions to aid in meeting and maintaining the NAAQS for both ozone and PM (EPA 1998). The assessment of the need for stricter standards was based on photochemical modeling performed for two other rule-makings: the 8-hr ozone NAAQS and the “Ozone Transport Assessment Group SIP Call”—an EPA rule to promote regional emissions reductions in the eastern United States. Both analyses showed that projected air quality under the existing mobile-source standards would result in several areas nationwide in violation of the 1-hr-average and 8-hr-average NAAQS for ozone and the NAAQS for PM10.6

Technical Feasibility Assessment

Projected Technologies

EPA and CARB assess technical feasibility through discussions (some confidential) with auto manufacturers, catalyst and other parts manufacturers, and suppliers. In addition, both agencies rely on bench-scale demonstrations that vehicles can attain the standards. The demonstrations are performed by various groups, including in-house and outside contractors and manufacturers. EPA and CARB present very similar lists and discussions of projected technologies to meet the Tier 2 and LEV II exhaust standards, respectively (Table 6-5). The technologies in the table represent different options that manufacturers could potentially use to meet the standards, although manufacturers can meet the standards with any combination of technologies. The majority of the technologies were already being used to meet the LEV and NLEV standards, and both agencies stated their expectation that those technologies could be improved to achieve even lower emissions. The exception was the advanced catalyst systems that CARB and EPA both projected would exist at the time of implementation. Advanced catalysts were thought to play

6  

Particles with an aerodynamic equivalent diameter 10 μm.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-5 Ex Ante Estimates of Most Likely Technologies to Meet the CARB LEV II and EPA Tier 2 Standards, Respectively

Technology Type

CARB

EPA

Technologies for improving fuel control

Dual oxygen sensors

Universal exhaust gas oxygen sensors

Individual cylinder air-fuel control

Adaptive fuel control systems

Electronic throttle control systems

Engine calibration techniques

Dual oxygen sensors/fast light-off exhaust gas oxygen sensor

Universal exhaust gas oxygen sensors

Individual cylinder air-fuel control

Adaptive fuel control

Electronic throttle control systems

Faster microprocessor

Fuel atomization and delivery

Sequential multipoint fuel injection

Heated fuel injectors

Air-assisted fuel injectors

Improved induction systems

Sequential multipoint fuel injection

Air-assisted fuel injection

Multiple valves and variable valve timing

Enhanced catalytic converter performance

Heat-optimized exhaust pipes

Leak-free exhaust systems

Close-coupled catalysts

Electric air injection

Electrically heated catalysts

Hydrocarbon adsorber systems

Increased catalyst loading

Improved high-temperature washcoats

Abbreviated engine start system

Heat- optimized exhaust pipe

Leak- free exhaust system

Close-coupled catalyst

Secondary injection of air into exhaust

Manifold with low thermal capacity

Adsorbers/traps

Increased catalyst volume and platinum group metal loading

Improved catalyst washcoats

Retarded spark timing at start-up

Reduced base engine out emissions

Full electronic exhaust gas recirculation

Engine designs to reduce oil consumption

Reduced combustion chamber crevice volumes

Full electronic exhaust gas recirculation

Engine modifications

Improved combustion chamber design

Sources: CARB 1998a; EPA 1999A.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

an important role in meeting the current California and federal standards (Bertelsen 2001).

The LEV II program also introduced much more stringent evaporative emissions standards for NMHC compared with LEV I. The CARB staff paper presents a discussion of these standards and the technologies expected to achieve them. The standards targeted diurnal and hot-soak fuel emissions and were projected to be met through a combination of better seals and less permeable equipment in the fuel tanks and fuel lines. EPA noted in its Tier 2 rule-making that manufacturers were already certifying vehicles below the level of the Tier 2 evaporative emissions standards; the RIA for the Tier 2 rule-making includes only an abbreviated discussion of evaporative emission-standard technical feasibility. The remaining assessments will focus on the exhaust emissions standards.

Evidence Provided by CARB on Technical Feasibility of LEV II Standards

As one piece of evidence that the LEV II standards were technically feasible, CARB noted that many of the projected LEV II technologies had been in use on vehicles for several years (CARB 1998a). CARB also noted the continuous evolution of emissions-control technologies since the introduction of the original LEV program and noted that the durability and performance of existing components, especially catalysts that heated quickly, had improved greatly.

CARB presented results from two test programs as evidence that vehicles could meet the proposed LEV II emissions limits. In the first program, CARB tested five model-year 1997-1998 passenger cars. The primary modification to all vehicles was the addition of an advanced catalyst system, although other modifications were required, namely, air injection time, oxygen sensor biasing, and ignition retard. The staff paper showed that all vehicles attained emissions below the 50,000-mi LEV II—ULEV level using “green” catalysts. One vehicle was tested after catalysts and oxygen sensors were bench-aged (a technique used at the Southwest Research Institute to simulate 50,000 miles of use) to 50,000 miles, and it met the standards. The test program did not attempt to determine compliance with SULEV standards, although CARB cited some manufacturers’ intentions at the time to introduce advanced technology vehicles, such as hybrids, as evidence of meeting SULEV standards.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

In the second program, CARB tested two identical SUVs with test weights of 6,000 lb (LDT 2). The new vehicles, as received, showed baseline NOx and CO emissions below and NMHC emissions slightly above proposed LEV II levels. Oxygen sensors and advanced catalysts were bench-aged. The sensors and catalysts were then added to the two new vehicles, which yielded emissions higher than proposed LEV II levels in many of the tests. CARB reasoned that emissions would be lower with appropriate adjustments to the software that controlled fuel delivery. CARB was not capable of developing such software, but it believed that manufacturers could. CARB modified its test preconditioning methods to simulate the effects of controlling the fuel and adding electronic air injection to one test vehicle in addition to the bench-aged advanced catalysts and oxygen sensors. Subsequent tests attained NHMC, CO, and NOx emissions just below proposed LEV levels in some tests.

CARB did not perform a feasibility analysis for the heavier trucks (LDT 2 category, 6,000-8,500 lb). The difficulty in achieving the LEV II standards on such vehicles was a primary critique from auto manufacturers during the LEV II rule-making (CARB 1999). CARB (1998a) noted that it had little information about fuel and spark timing strategies that were likely to be part of the manufacturers approach to reducing emissions.

Evidence Provided by EPA on Technical Feasibility of Tier 2 Standards

In its review of model-years 1999 and 2000 certification data, EPA found that several existing engine families already met the new Tier 2 standard NOx and NMHC fleet averages (EPA 1999a). For model-year 1999, 48 of approximately 400 engines included at least one vehicle configuration, mostly for passenger cars, certified to meet lifetime NOx emissions below the average of 0.07 g/mi of the proposed emission standard. Approximately half of those vehicles were certified to meet lifetime NOx levels below 0.04 g/mi.

EPA further cited results from outside testing to support feasibility of Tier 2 standards. Results from fuel sulfur-level testing by the Coordinating Research Council and auto manufacturers showed the potential to go as low as the Tier 2 emissions standards. Seven of 20 LDVs with 100,000-mile-aged catalysts met Tier 2 NOx and NMHC standards by

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

switching to low-sulfur fuel. Vehicle testing at Southwest Research Institute, sponsored by the Manufacturers of Emissions Controls Association (MECA), demonstrated that two LDVs and one LDT met the Tier 2 NOx and NMHC standards by replacing the original catalysts with advanced catalysts and by modifying existing secondary air and exhaust gas recirculation. Most vehicles met NOx and NMOG useful-life design targets, which are generally 50-70% of the standards. Finally, EPA cited the results of CARB’s test programs (described above) to demonstrate the feasibility LEV II standards and the evidence that the technology was available to meet Tier 2 standards.

EPA used evidence from external testing but also conducted its own testing program to investigate the feasibility of requiring heavy LDTs (>6,000 lb GVW) to meet the Tier 2 standards at intermediate useful life (50,000 miles). EPA stated that a key element of this test was alteration of engine calibration parameters, including modification of spark timing, exhaust-gas recirculation (EGR), and fuel control. These modifications were made in addition to use of improved catalysts, including increases in volume and precious metal loading and higher cell densities, thermally aged to an equivalent 50,000 miles. Both trucks tested attained NOx and NMHC emissions below Tier 2 standards in the final tested configurations. EPA stated that considerable tuning of the engine calibration parameters for one vehicle was necessary to reduce NOx and NMHC emissions, particularly from the initial cold-start phase of the federal test procedure, and to minimize impacts on drivability and fuel economy. Cold-start NOx emissions were further reduced for this vehicle by using improved low-mass, sealed air-gap exhaust manifolds. EPA also stated that technologies and emissions-control strategies implemented for these heavy LDTs could be used to meet the more stringent standards for MDVs.

Emissions and Air Quality Impacts Assessment

CARB and EPA use similar tools to measure emissions and air quality impacts of proposed regulations, but to different ends. CARB used its own mobile-source emissions model, EMFAC97G, to estimate that the LEV II program would result in a reduction of 6 tpd of ROG (exhaust and evaporative), 51 tpd of NOx, and 120 tpd of CO in the South Coast basin by 2010 (CARB 1998a). CARB staff determined that these reductions would fulfill the M2 SIP control measure, would pro-

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

FIGURE 6-2 Forty-seven-state (excluding California) NOx emissions with the Tier 2/sulfur rule. Vertical axis represents annualized summer tons (tons per year) of NOx emissions. EPA used two different models of analysis. Source: EPA 1999a.

vide additional reductions toward shortfalls in other programs, and would make progress toward the black-box reductions (M2 and black-box reduction control measures for the South Coast discussed earlier in the chapter). The analysis for the LEV II rule-making did not include any additional photochemical model runs to assess the precise impact on air quality in the South Coast or elsewhere in California. AQMDs in California, including the South Coast, include new LDV emissions reductions when they use modeling to demonstrate attainment of the NAAQS.

EPA used the Tier 2 emissions model, which was similar in function to the planned (at the time) MOBILE 6 emissions model, to project benefits of Tier 2 on nationwide on-road emissions. Figure 6-2 shows a chart from the RIA showing the benefits in NOx emissions in the lower 47 states (excluding California) with and without the proposed Tier 2 rule (“without” assumed existing NLEV standards for LDV and LDT 1 and Tier 1 standards for LDT 2). In further modeling, EPA used the urban airshed model (UAM), a photochemical grid model, to estimate the impact on ozone pollution with and without the Tier 2 regulations. Two modeling domains were used (East U.S. and West U.S. domains); two episodes were run for the West domain, and three episodes were run for the East domain, where each episode had a different set of meteorologi-

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

cal inputs. Each episode was run for a combination of base-year (1996) and future-year (2007 and 2030) emissions. Results of the UAM showed that the number of exceedances of the 1-hr ozone standard was expected to decrease by one-tenth in 2007 and one-third in 2030 in metropolitan areas as a result of the Tier 2 rule. EPA also presented further analysis of the expected Tier-2-related reductions in emissions of PM, diesel PM, and HAPs. The RIA includes estimates of the benefit of Tier 2 regulations on nonattainment of the PM10 NAAQS. EPA further quantified and monetized the health and welfare impacts from this range of air quality improvements (discussed below in benefits section).

The analysis of emissions and air quality benefits for each rulemaking highlights some similarities and differences in the agencies’ practices in setting emissions standards. CARB and EPA consider technical feasibility by examining how a small subset of vehicles could be redesigned to achieve the proposed standards. CARB sets statewide emissions standards focusing on meeting air quality standards in the worst nonattainment area in the state. An overall emissions budget is developed by AQMDs as part of the SIP planning. The LEV II standards are then developed to achieve as many reductions they perceive to be technically possible to meet the budget. CARB does not examine the air quality benefits of their regulations in isolation from other SIP measures in each AQMD. CARB’s LEV II regulations do not include monetary estimates of public health benefits. In EPA’s case, standards are set with the primary goal of bringing all of the nation’s nonattainment areas closer to attainment, although NAAQS attainment is ultimately a state responsibility. EPA did estimate future emissions, air quality, and health benefits from its proposed Tier 2 standards because it qualified as a major regulation.

Cost Estimates, Cost-Effectiveness, and Benefits Analysis

CARB and EPA looked at the potential costs of implementing the standards and performed some cost-effectiveness analyses that allow comparison of the relative costs of the standards with the costs of other emission-reduction plans. EPA also performed a cost-benefits analysis for the Tier 2 standards. The committee describes the estimates and analyses below.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×
Cost Estimates

Ideally, costs should be estimated in connection with the expected emissions reductions from setting standards. The costs of achieving a given standard are closely linked to the expected emissions reductions. The level of emissions reduction predicted for the standard should include realistic assumptions about the amount of compliance with the program, the number of vehicles sold, and the effectiveness of controls over the life of the vehicle. If those outcomes or conditions will require additional costs, those costs must be taken into account.

As described in Chapter 5, it is critical when estimating costs to be clear about what constitutes the baseline to which the changed standard is being compared. The incremental costs of changing a vehicle to meet the California SULEV standard will be different if they are compared with the ULEV II standard or with an earlier less stringent standard, such as the LEV. Sometimes, the cost estimates in the regulatory documents are not clear on what standards are being compared.

CARB Cost Estimates

CARB bases its estimates of the cost of compliance with proposed new standards on estimates of the full consumer costs to meet the standards, assuming that such costs are fully passed on. These estimates include variable costs (equipment, assembly, and warranty), support costs, (research and development), investment costs, and dealer costs. (The approach is similar to that detailed in Wang et al. [1993].) In the early years of the California LEV program, there was a great deal of uncertainty about the potential costs of meeting the LEV standards. Table 6-6 summarizes the estimates by CARB and automakers of costs of meeting the LEV standards per vehicle compared with the federal Tier 1 standards and averaged across the California fleet. The ex ante (preproduction) costs estimated by the automakers in 1994 were much higher than the CARB estimates.

In the case of the LEV standards, the actual average cost per vehicle, based on analysis of CARB staff, appear to be much closer to CARB’s original estimate than the manufacturer’s estimate. CARB reassessed the costs periodically over time as evidence became available about the actual attainment of standards on certain vehicles. The ex post

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-6 Estimated Average Cost per Vehicle of California LEV Compared with Tier 1 and Averaged Over the Fleet

 

Cost per Vehicle

Preproduction estimates

CARB (1990)a

$170

Sierra Research (1994)

$788

Postproduction estimate

CARB (1996)a

$120

aWeighted average of four-, six-, and eight-cylinder vehicles.

Sources: CARB 1990, 1996; Sierra Research 1994.

TABLE 6-7 Estimated Average Cost per Vehicle to Meet California LEV Standard Compared with the Tier 1 Standard (Cost per Vehicle)

Vehicle and Enginea

CARB Preproduction Estimate, 1994

CARB Estimate Based on Actual Production, 1998

Honda Civic, four cyl.

$86

$76

Toyota Camry, six cyl.

$137

$79

Ford Crown Victoria, eight cyl.

$139

$152

aCosts are to meet the standards for the LEV type, not the other types under the LEV program.

Source: Cackette 1998.

(postproduction) estimate in Table 6-6 shows per vehicle cost averaged across the fleet from the CARB ex post analysis. Average actual costs were even less than the California ex ante estimates to meet the LEV standards. Table 6-7 summarizes the pre- and postpreproduction estimates of costs for the individual vehicles used to obtain the fleetwide averages. The costs of the four- and six-cylinder vehicles were higher ex ante than ex post. This difference was primarily due to lower catalyst cost than anticipated. The eight-cylinder vehicle cost was higher in production than estimated in earlier studies. For that vehicle, costs were slightly higher for equipment and materials, as well as for support and other components.

For the LEV II standards, CARB used a similar approach to determine ex ante average costs per vehicle. Costs were estimated for vehicles of different engine sizes during the time the LEV II standards were being proposed in 1998. An example of the component cost breakdown of vehicles to meet ULEV II over ULEV I standards presented in the staff paper is given in Table 6-8. Engine class costs are then weighted by the

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-8 Passenger Car and LDT 1: Incremental Component Costs of a ULEV II Compared with a ULEV I

Emissions-Control Technology

Incremental Cost ($)

Four cyl.

Six cyl.

Eight cyl.

UEGOa

0

0

0

Air-assist fuel injectionb

0

0

0

Individual cylinder fuel controlc

0

0

0

Retarded spark timing at start-upc

0

0

0

Low thermal capacity manifold (upgrade)

10

20

20

Greater catalyst loadingd

14

22

37

Improved double-layer washcoat

2

3

5

Engine modificationse

0

10

15

Air injection (electric)f

0

33

33

Total incremental component cost

26

88

110

NOTE: Incremental cost represents an average across different models and is based on the estimated component cost multiplied by the additional fraction of new ULEV II models that are projected to use the technology. When an incremental cost is zero, it indicates that the same fraction of ULEV I models used the technology as the fraction of ULEV II models that are projected to use it. Cost estimates are rounded to nearest dollar and retotaled.

aOnly the front oxygen sensor is a universal exhaust gas oxygen (UEGO) sensor.

bAir- assisted fuel injection requires minor redesign of the idle air control valve at no cost and addition of an adaptor to each injector at a cost of $2 each.

cIndividual cylinder fuel control and retarded spark timing at start up require only software changes at no additional hardware cost.

dCatalyst volume on a ULEV II is estimated to be the same as it is on a ULEV I vehicle.

eTypes of engine modifications may be less uniform throughout the industry and may include such items as an additional spark plug per cylinder, a swirl control valve, or other hardware needed to achieve cold-combustion stability, improved mixing, and better fuel injector targeting.

fCost of air injection includes an electric air pump with integrated filter and relay, wiring, air shutoff valve with integral solenoid, check valve, tubing, and brackets.

Source: Modified from CARB 1998a.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

shares of vehicles of different types to find the average costs of meeting the standards. Table 6-9 shows those estimated average costs of meeting the ULEV II and SULEV components of the LEV II program. The costs are generally higher for larger vehicles. In fact, the CARB estimates (CARB 1998a) for SULEV costs are mostly for the four-cylinder engines and a few six-cylinder engines. At the time of the study, CARB engineers believed it likely that most SULEVs would be four-cylinder due to the potential difficulty of meeting the standard for the larger vehicles.

EPA Cost Estimates

EPA, in setting standards, is directed to consider “the need for, and cost-effectiveness of, obtaining further reductions in emissions” (CAA section 202(i)(2)(A)). EPA uses a similar approach for estimating the costs per vehicle similar to the approach of CARB except that EPA develops both short-term and long-term estimates. EPA first assesses the costs of the standards to manufacturers, including variable costs (hardware and assembly), fixed costs (research and development, retooling, and certification), and operating costs (fuel use, fuel cost, and maintenance). The hardware component of the manufacturer’s costs are then assumed to be marked up for retail sales to consumers. Cost estimates are made separately for LDVs, the different LDT types, and different engine sizes (four, six, and eight cylinder). EPA attempts to estimate costs (and emissions reductions) for the larger vehicles (for example, 10 cylinder) as compared with CARB analysis. EPA’s costs are projected for both variable- and fixed-cost components over the short term, assuming that capital cost recovery will occur in 5 years.

Over the long term, however, cost per vehicle is assumed to fall due to learning, which is the ability to produce lower-emitting vehicles more efficiently.7 EPA assumes in their Tier 2 analysis that costs will fall to 80% of their earlier value after 2 years in production and will not decrease after that due to learning. Costs per vehicle are estimated to stay the same after 5 years when fixed costs expire. Costs are estimated to be much higher for the larger vehicles. For example, the heavier light-duty trucks (known as LDT 3 and LDT 4) are projected to cost $202 more than an NLEV vehicle, compared with only $70 more for a passenger car and lighter light-duty trucks than an NLEV (both long-run estimates).

7  

For a more complete discussion of the effect of learning on costs, see Chapter 5.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-9 Ex Ante Estimates of the Costs per Vehicle for Meeting the LEV II and Tier 2 Standards (dollars per vehicle)

Source

ULEV-LEV II Compared with ULEV-LEV I

SULEV Compared with ULEV-LEV II

Tier 2 Compared with NLEVa: Short term (1-2 yr) per Long term (6+ yr)

CARB 1998a

PC $71

PC $131

 

 

LDT 1 $46

LDT 1 $105

 

 

LDT 2 $184

LDT 2 $279

 

 

MDV 2 $208

 

 

 

MDV 3 $209

 

 

 

MDV 4 $134

 

 

EPA 1999a Chapter V

 

 

LDV $70/$42

 

 

 

LDT 1 $63/$39

 

 

 

LDT 2 $107/$80

 

 

 

LDT 3 $202/$161

 

 

 

LDT 4 $212/$169

aNot specified to which bin the vehicle is certified.

Sources: CARB 1998a; EPA 1999a.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

Estimated costs of the federal Tier 2 standards are similar to the California ULEV vehicles, as shown in Table 6-9. In fact, the Tier 2 costs were derived in part from the work that CARB had done on costs for LEV II.

The Union of Concerned Scientists re-analyzed EPA’s cost estimate for the average 6-cylinder LDT 2 to assess the costs of meeting the Tier 2 requirements for a Ford Explorer (Mark 1999). They estimated a short-run cost of $138 over a similar NLEV vehicle, which is close to the average LDT 2 estimate by the EPA.

Cost Estimates for Advanced Technology Vehicles

Estimates of the costs for vehicles that will meet the more stringent standards of the California LEV II program are examined here. Table 6-10 shows the estimated incremental costs of PZEVs, AT-PZEVs, and ZEVs taken from different sources. There is a substantial difference in costs between the CARB estimates and other estimates for the PZEVs and AT-PZEVs. A number of PZEVs are already on the road, and these initial models tend to be passenger cars with smaller engines (CARB 2005f, CARB 2006a). AT-PZEV estimates in Table 6-10 refer to gasoline hybrid electric vehicles. A few hybrid models are in production today; however, technology types and costs under future high-volume production scenarios are uncertain, which probably accounts for some of the variability in cost estimates in Table 6-10.

Overall estimates of the costs of these vehicles require assumptions about advancements in technology and distribution of sales across the fleet. There are a range of possible fleet distributions that would result in the standard being met. The actual distribution of types of vehicles actually sold will depend on vehicle prices and consumer preferences. It is difficult to project far into the future what public preferences will be, but some range of plausible fleet distributions might be important to consider. One CARB estimate is that by 2012, the fleet will have to be close to 60% PZEVs to meet the LEV II standards (CARB 2005f). It is not entirely clear how the per-vehicle costs are aggregated across the fleet to meet the standard in the CARB assessments. Small vehicles (four-cylinder) are assumed to be sold in sufficient numbers to meet the 60% PZEV level at the assumed costs. If not, then the costs of having larger vehicles meet the standards would have to be assessed. In several places, the California analysis (CARB 1998a) provides some evidence that CARB and the automakers expect full-sized trucks, SUVs, and vans to

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-10 Incremental Manufacturer Cost Estimates of PZEVs, AT-PZEVs, and ZEVs (dollars per vehicle)

Source

PZEVs

AT-PZEVsa

ZEVs

City EV

Full EV

Fuel Cell

CARB 2003c

$100 compared with SULEVs

$3,300 (2003-2005)

$1,500 (2006-2008)

$1,200 (2009-2011)

$700 (2012+) compared withSULEVs

$8,000

$17,000

$1,000,000 (2003-2005)

$300,000 (2006-2008)

$120,000 (2009-2011)

$9,300d (2012 + )

Dixon et al. 2002b

$60-$230 comparedwith SULEVs

$2,300-$3,300 compared with SULEVs

$5,300-$13,400

$8,000-$26,100

$8,300-$15,200 (2006-2010)

Austin 2005

$740

$6,355c

 

 

 

aAT- PZEV in these analyses refer to gasoline hybrid electric vehicle. Estimates do not account for gasoline savings from higher fuel economy. There are likely important differences between studies in the assumed types and costs of technologies that constitute the AT- PZEV.

bEstimates for AT- PZEVs and ZEVs for 2003-2007, before high-volume production of these vehicles, except where noted.

cBased on variable technology costs for gasoline hybrids found in NESCCAF 2004.

dLong-term fuel cell costs based on Browning 2001.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

have the greatest difficulty in meeting the standards. An important question that was raises is whether preferences will shift from those vehicles, or whether the standards will be developed for the larger vehicles at higher cost. Given the uncertainty, a range of estimates based on possible outcomes would provide a more thorough assessment.

The estimated costs of the ZEV mandate are notably high for the more distant years, when at least some pure ZEVs must be sold. In all analyses, the assumption is made that over time and as production volumes increase, the costs of producing these vehicles will fall (learning will occur). There is, however, a great deal of uncertainty about what the costs will eventually be and how low they will fall. As described earlier in this chapter, CARB’s early estimates of the costs of electric vehicles were low and then the estimates increased over time as implementation of the technology was found to be more difficult. Conversely, by CARB’s analysis, LEV costs were lower than expected.

The estimates in Table 6-10 account for the costs of producing ZEVs, but the assumption of how they will be sold to the public is not clear. Fleet distribution issues and how they figure in to the cost estimates are not well explained. If vehicles are not appealing to the public, it will be difficult to sell them without subsidies. The state of California has subsidized the purchase of ZEVs in the past (CARB 2000a), and other financial incentives exist at the local and federal levels to purchase clean vehicles (CARB 2006b, CARB 2005f). In such cases, the vehicle purchasers and taxpayers share the cost of bringing vehicles to the market.

Cost-Effectiveness

EPA and CARB provide estimates of cost-effectiveness of the LEV II and Tier 2 regulations, on basis of the costs and pollutant reductions described above. The reader is referred to CARB (1998a) and EPA (1999a) reports for more details. Table 6-11 shows the cost-effectiveness of the advanced-technology component of the LEV II program. ATPZEV cost-effectiveness estimates include fuel savings over the life of the vehicle, which necessarily involve assumptions about fuel use and cost. The cost-per-ton-reduced estimates for the ZEV mandate are higher than most other air emissions-control programs. California acknowledges that, but argues that the program has the broader goal of pushing the automakers to develop alternative cleaner technologies.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-11 Estimates of Cost-Effectiveness of Advanced Technology Vehicles (dollars per ton pollutant reduced over the lifetime of the vehicle)

Source

PZEVs

AT-PZEVsa

CARB 2004b

$44,000 per ton ROG + NOx compared with SULEVs

$575,000 per ton ROG + NOx (2005)

$125,000 per ton ROG + NOx (2006-2008)

compared with SULEVs

Dixon et al. 2002b

$18,000-$71,000 per ton NOx + NMOG compared with SULEVs

$650,000-$1,800,000 per ton NOx + NMOG compared with PZEVs

Austin 2005

$65,000 per ton NOx + NMOG (assumed to be near term)

$3,000,000 per ton NOx + NMOG c (assumed to be near term)

aAT-PZEV in this analysis refers to a gasoline hybrid electric vehicle. In contrast to Table 6-10, these cost-effectiveness estimates include potential fuel savings. Please see corresponding references for methodologies.

bEstimates for AT-PZEVs in 2003-2007 before high-volume production of these vehicles.

cBased on variable technology costs for a gasoline hybrid in NESCCAF 2004

Benefits Estimates

EPA and other federal agencies are required by Executive Order 12866 and supplements to perform a benefits-cost analysis (BCA) for all major regulations, including the Tier 2 standards. The Tier 2 emissions standards include a BCA described as having four parts: calculation of the emissions impacts of the rule in a future year, estimation of the air quality and environmental change from the rule in the future year, determination of the health and welfare effects in terms of physical effects and monetary value, and calculation of the costs of the standards in the same future year for comparison to monetized benefits (EPA 1999a). EPA estimates benefits occurring in the year 2030 when the entire fleet is expected to be nearly turned over and to consist of mostly Tier 2 vehicles. Because the fleet in this year would represent a nearly complete implementation of the rule, the year would include “the maximum emission reductions (and resultant benefits) and…the lowest costs…on a per mile basis”; and therefore “the resulting benefit-cost ratio will be close to its maximum point” (EPA 1999a).

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

The emissions and air quality impacts of the rule are calculated using models like those described for environmental impacts; however, it appears that the air quality analyses were repeated specifically for the benefits analysis because the future year was different. Air quality changes included ambient ozone and PM concentrations, airborne nitrogen deposition, and visibility. The health outcomes associated with changes in air quality that EPA considered included both premature mortality and incidences of nonfatal health effects such as asthma. Welfare outcomes considered by EPA included material damage, economic output, visibility, and nutrient loading. The health benefits for the Tier 2 rule are presented in Table 6-12.

The discussion in the RIA notes the difficulties in quantifying and monetizing changes in many of the end points. As a result of these difficulties, some health and welfare outcomes were not quantified and are discussed only qualitatively. In earlier analyses, EPA assessed uncertainty by sensitivity analyses. The RIA includes a qualitative discussion of the uncertainties in estimating benefits and monetizing these benefits. In the Tier 2 rule, information about the possible distribution of benefits was considered for a more statistically accurate estimation of benefits. Uncertainty surrounding cost estimates was not examined. Benefits estimation from air quality regulations was the subject of a separate National Research Council study (NRC 2002b). This NRC study used the benefit estimation from EPA’s Tier 2 rule as one of three case studies, and the reader is referred to the NRC (2002b) report for more discussion on EPA’s benefits estimation practices.

Two of the most important health benefits of the Tier 2 rule shown in Table 6-12 were PM related: an estimated 4,300 annual avoided cases of premature mortality and 2300 annual avoided cases of chronic bronchitis. EPA presented a preferred estimate of $25 billion (1997 monies) for the benefits from the Tier 2 rule in 2030, not including benefits that were not monetized (EPA 1999b). Twenty-three of the $25 billion account for the health benefits of reduced premature mortality associated with reduced PM concentrations. EPA noted that the estimate is dependent on the method used to value reduced mortality, namely the value of a statistical life (VSL) estimate, which is itself uncertain. EPA also included alternative estimates of the benefits under scenarios where major assumptions were changed. Total costs of the Tier 2 program were developed using the same basis as the benefits analysis (2030 with a full Tier 2 fleet) and methods described earlier in this section. The total costs were estimated to be $5.3 billion (1997 monies).

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-12 Annual Health Benefits (Avoided Cases of Mortality and Morbidity and Monetized Value) for Tier 2 Regulation in 2030

Health Outcome

Avoided Casesa

Monetized Benefit (1997 $ in millions)b

PM-Related Health Outcomes

Premature mortality (adults, ages 30 and over)

4,300(2,700-5,900)

23,380

Chronic bronchitis

2,300 (600-4,100)

730

Hospital admissions

 

 

Respiratory causes

1,200 (400-2,100)

10

Cardiovascular causes

500 (100-1,100)

10

Emergency room visits for asthma

900 (400-1,400)

<1

Acutebronchitis (children, ages 8-12)

7,900 (0-16,300)

<1

Lower respiratory symptoms (children,ages 7-14)

87,100 (39,900-131,100)

<5

Upper respiratory symptoms (children with asthma, ages 9-11)

86,500 (25,500-144,600)

<5

Shortness of breath (African Americans with asthma, ages 7-12)

17,400 (4,700-29,500)

<1

Work-loss days (adults, ages 18-65)

682,900 (597,8007-71,800)

70

Minor restricted-activity days and acute respiratory symptoms

3,628,500 (3,034,100-4,177,200)

170

Ozone-Related Health Outcomes

Chronic asthma (adult males, ages 27 and over)

400 (100-800)

10

Hospital admissions

Respiratory causes

1,000 (200-1,800)

10

Cardiovascular causes

300 (0-500)

<5

Emergency-room visits for asthma

400 (100-600)

<1

Minor restricted-activity days and acute respiratory symptoms

2,226,500 (1,014,400-3,414,800)

100

Decreased worker productivity (adult working population)

Not reported

140

aMean value provided with 5th and 95th percentile values shown in parentheses rounded to the nearest 100.

bMean value of monetized value provided for reference.

Source: NRC 2002b. Adapted from EPA 1999a,b.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×
Assessment of Approaches Used to Evaluate Stricter Standards

Although the costs for individual vehicles were estimated and the methods documented, it was less clear how costs were aggregated to the fleet level for CARB and EPA. Assumptions about fleet sales and vehicle size mix are important in assessing costs, as discussed above. A related point is that the areas of greatest uncertainty in costs are not addressed. It is clear that there is uncertainty in forecasting costs and emissions reductions, but there are few cases where uncertainty in the costs estimates are assessed. Particularly for future technologies, for which there is a great deal of uncertainty in benefits and costs, some reflection of that uncertainty would be important in assessment of the standards. CARB attempts to reassess costs and emissions reductions as new evidence becomes available about actual methods, costs, and performance. EPA has no requirement to reevaluate or provide ex-post assessments.

There are other costs besides the per vehicle costs that might be important for implementing stricter standards, particularly if those standards are not uniform. The committee found little information about the actual costs of dealing with noncompliant cars, border issues, or other costs of enforcement. However, CARB issues annual reports on enforcement activities that detail the enforcement of mobile-source emissions standards in the state. States adopting the California standards would need to assess whether they would face similar or different compliance issues and costs.

A final important point about the cost analyses is how emissions controls affect the price of the vehicle. This issue is important for assessing not only what the costs may be but also who will pay them. The CARB estimate of the costs of the LEV standards assumes that the costs are paid by buyers of the LEV II vehicles. The estimated average costs per vehicle reflect the costs of the control equipment and a share of the other costs of design and production. However, pricing of vehicles is complex (Sperling et al. 2004a) and does not always reflect the single vehicle cost. There are important marketing and sales considerations. For some vehicles, the emissions costs are likely to be at least partially reflected in the sticker price. If a vehicle type has two versions with different characteristics that consumers can identify, such as a Ford Escape and a Ford Escape Hybrid, the manufacturer can charge different prices. Differences in fuel economy and other features are evident to car buyers

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

and they will pay for different features.8 For vehicles that are identical, however, except for the emissions equipment, the price charged might have to be the same for both types of vehicles.9 Therefore, costs are spread across a portion of, or the entire, U.S. vehicle fleet when some states adopt a stricter standard.

ADOPTION OF LEV BY AUTHORITY OF SECTION 177 OF THE CLEAN AIR ACT

In September 1990, New York became the first state to use its authority under section 177 of the federal CAA to adopt California standards by adopting CARB’s pre-LEV emissions standards. In October 1991, the 13 Northeast states that were the members of the Ozone Transport Commission (OTC), created by the 1990 CAA amendments, pledged to individually adopt the California LEV standards in their respective states. Massachusetts became the first state to adopt the California LEV standards on January 31, 1992. This action was compelled by a state statute passed in 1990 that required the Massachusetts Department of Environmental Protection to adopt and implement California motor vehicle emissions standards unless the agency can demonstrate, based on substantial evidence, that the California standards will not achieve greater pollution reduction than the federal motor vehicle emissions-control program (M.G.L. c. 111, § 142K). New York followed suit and became the second Northeast state to adopt the California LEV standards in May 1992, followed by Maine in 1993. Most other OTC states, however, did not originally adopt the LEV standards in the face of strong opposition by the auto and oil industries (including a series of federal lawsuits) and skepticism about the benefits of the program by legislators in some states. Some states (for example, Pennsylvania and New Jersey) conditionally adopted the LEV standards to take effect in those states only if a sufficient number of other Northeast states also implemented the program.

8  

Fuel economy savings are not always accurately accounted for in consumer vehicle purchase decisions. See Turrentine and Kurani (2005) for a discussion of that point.

9  

One car company told the committee that the same price must be charged for vehicles that look identical except for the emissions-control equipment. Another company representative made the different point that regions accept higher prices when different controls are required in their regions, such as under LEV II.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

State-by-state adoption of the LEV program in the entire Northeast region faltered, and on February 1, 1994, the OTC voted 9-4 to recommend to EPA that it mandate adoption of the California LEV standards in the entire region. Virginia, Delaware, New Hampshire, and New Jersey dissented. After extensive proceedings, EPA decided in September 1994 to approve the OTC request and mandated adoption of the LEV standards in all 13 Northeast states on the grounds that such action was necessary to achieve attainment of the NAAQS in the region. EPA determined that states could elect to adopt the California LEV program without the ZEV mandate component, because the ZEV component was a separate requirement, but states would need to comply with the NMOG fleet-average requirement and thus would be required to achieve additional reductions in their LEV programs to replace the expected ZEV contribution to the NMOG fleet average.

Virginia and the vehicle manufacturers went to federal court to challenge EPA’s authority to mandate adoption of the LEV standards in the Northeast states. The court held that a state’s authority to adopt to the California program under section 177 of the federal CAA was intended to be voluntary and could not be compelled by EPA (Virginia v. EPA, 108 F.3d 1397 [D.C. Cir. 1997]). Moreover, the court held that the EPA decision unlawfully circumvented the provision in the CAA that prohibited EPA from adopting new motor-vehicle emissions standards before the 2004 model year.

By the late nineties, New York, Massachusetts, Maine, and Vermont were the only states to have voluntarily adopted California’s LEV program. Implementation began in 1994, 1995, 2001, and 2000, respectively. All four states have since adopted the LEV II regulations that began in model-year 2004. New York and Massachusetts have always included the ZEV mandate as part of their regulations. Maine initially adopted the ZEV mandate but repealed it during adoption of LEV II in 2000. In 2005, however, Maine reinstated the ZEV mandate to begin in model-year 2009. Vermont adopted the ZEV mandate in 2001, but later stated that manufacturers were not required to meet the mandate for model-years 2001-2005. In 2005, Vermont re-affirmed the ZEV mandate to begin in 2007. Each state adopted the ACP option and offered credits toward fulfilling the ZEV requirement. Following California’s adoption of LEV II standards, Connecticut, Rhode Island, and New Jersey adopted the California on-road emissions standards, including the ZEV requirement, ACP, and credit system. Implementation of LEV II standards and various components in these states are not scheduled until at least model-year 2008 and have different implementation dates and deadlines.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

States’ Rationale for Adopting California Emissions Standards

Adoption of the LEV standards in the Northeast has remained a state-by-state issue. States that adopted the LEV program, led by New York and Massachusetts, concluded that the adoption of such standards was a necessary and cost-effective measure to attain the NAAQS. For example, New York said that it was compelled to adopt the California standards because the “emission reductions provided by the adoption of the LEV standards along with a wide array of other mobile, stationary and area source control programs are necessary to attain the NAAQS for ozone in New York as required by federal law” (NYDEC 1992). Other Northeast states came to contrary conclusions. For example, Connecticut decided against implementing the California LEV program because it concluded at the time that the program would be too expensive and would not provide sufficient and timely SIP credits (Dumanoski 1991). The primary reason for states to adopt the California standards has been to obtain additional emissions reductions to meet air quality goals. In each case, adoptions have been based on the conclusion that California emission standards would provide greater mobile-source emissions reductions more quickly than federal standards. That conclusion was almost certain when California’s original LEV program began, since EPA was not expected to introduce more stringent Tier 2 standards, if at all, until model-year 2004, as specified in the CAA.

The committee heard about other benefits of California emissions standards that seem to contribute, at least in part, to the rationale behind the adoption decision. One benefit is that the emissions differences between the California program and the federal program will probably become greater as California adopts more stringent phases of the LEV program (beyond LEV II) (NESCAUM 2003), recognizing that no successor to the current Tier 2 program is planned or mandated by the CAA. Regulatory documents from other northeastern states also point out that benefit, stating that the California program is more dynamic than the federal program and will likely be revised before the federal program (MEDEP 2004).

Recent state actions and statements also reflect a growing desire by states to reduce greenhouse gas (GHG) emissions. A statement made to this committee during a public session meeting, for example, reflected Connecticut’s position that adoption of the California LEV II standards provides an opportunity to achieve CO2 reductions to meet its climate plan, because the LEV II program provides incremental GHG emissions reductions over the Tier 2 program and California has added specific

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

GHG emissions standards to its program (McCarthy 2005). Additional discussion of these GHG standards is provided later in this chapter.

The automobile and oil industries have argued that the LEV II program is not a cost-effective or necessary program compared with the Tier 2 program, which they would otherwise be required to comply with. Manufacturers have also objected that northeastern states were placing the burden of handling costs on out-of-state vehicle manufacturers rather than imposing pollution-reduction costs on in-state industries. Manufacturers could point to such statements as that of Massachusetts Secretary of Environmental Affairs Susan Tierney, who was quoted as saying, “This is a jobs issue for Massachusetts. Every pound we don’t take out of automobiles, we have to take out of a sector that has a job at stake” (Dumanoski 1992). Manufacturers also argue that differences in LEV and LEV II implementation dates among the various states complicate vehicle distribution and sales for themselves and their dealers (Babik 2005) and that the additional costs do not outweigh the emissions benefits.

Novel Issues in State Adoption of California Emissions Standards

Beginning with the initial adoption of LEV in the Northeast, automakers and others have objected to states’ authority to adopt California emissions standards. Table 6-13 lists several of the objections. Manufacturers raised such objections in public comments to New York and Massachusetts as part of the early state rule-makings to adopt the California LEV standards. The states generally disagreed with the factual or statutory basis of the manufacturers’ arguments and proceeded with adoption of the LEV standards as proposed. Trade associations of vehicle manufacturers subsequently filed separate lawsuits in federal district court challenging the LEV standards in New York and Massachusetts.10 The litigation against the two states proceeded over 7 years and involved extensive motions, briefings, affidavits, discovery, and appeals that were both time-consuming and expensive for manufacturers and states. Twelve separate court decisions were issued by the federal trial and appellate courts for New York and Massachusetts, described in one treatise as “an epic series of court battles” (Wooley and Morss 2004).

10  

Manufacturers also filed a lawsuit against Maine’s adoption of the LEV standards, but that lawsuit was voluntarily dismissed when Maine agreed to indefinitely delay implementation of the LEV standards.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-13 Manufacturers’ Objections to Northeast States’ Adoption of the California Emissions Standards

• States adopted California’s emissions standards but not the cleaner-burning and lower-sulfur California fuel requirements that were part of the LEV program, resulting in reduced air quality benefits and adversely affecting the advanced emissions-control systems under development to comply with the LEV standards in California.

• The distribution of California-certified vehicles to other states would impose unnecessary burdens on product distribution and availability.

• Auto dealers located near state boundaries would be adversely affected and would be required to stock different versions of the same vehicle model.

• The electric vehicles produced to meet the ZEV mandate would primarily be powered by lead-acid batteries in at least the initial years of the ZEV mandate, and such batteries would produce a much lower range and poorer performance in the colder Northeast states than in California

• Massachusetts and New York adopted the California LEV standards before they had obtained a federal preemption waiver from EPA and without providing the full 2-year lead time required by section 177 of the federal CAA.

• The sales mix of a given manufacturer was different in Northeast states than in California, complicating and jeopardizing compliance with the NMOG fleet-average requirement in each opt-in state.

• The opt-in states failed to provide the same credit allowances provided by California for meeting the NMOG fleet-average and ZEV-mandate requirements.

• States failed to follow California’s modifications to its ZEV requirements, resulting in different versions of the LEV program in California and in other states.

The first lawsuit to proceed was in New York, where manufacturers alleged that (1) New York had violated section 177 of the federal CAA by adopting the LEV standards before they had received a preemption waiver and without providing the 2-year lead time required by section 177; (2) New York had failed to adopt the California clean-fuel regulations in conjunction with the LEV standards in violation of the section 177 requirements that state standards be “identical” to California’s and not have the effect of creating a “third vehicle”; and (3) New York would violate section 177's prohibitions of a “third vehicle” and restrictions on the sales of any category of California-certified vehicles in its ZEV mandate. The federal district court in New York initially held against manu-

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

facturers on some claims but in favor of manufacturers on the ZEV mandate violation and on the failure to adopt California’s accompanying fuel standards, requiring manufacturers to build a third vehicle because of the effects of high-sulfur gasoline on the advanced emissions-control equipment being developed to comply with the California LEV standards. In response to New York’s motion for reconsideration, the district court later reversed its decision on the fuels and third-vehicle claim and determined that a full trial would be required to resolve that issue.

In two decisions, the Second Circuit Court of Appeals ultimately held in favor of the state on all claims except the lead-time claim (Motor Vehicle Mfrs Ass’n v. NY Dep’t of Envtl Conservation, 17 F.3d 52 [2d Cir. 1994]). The Second Circuit construed the third-vehicle prohibition of section 177 narrowly to apply only to major changes in vehicle design directly required by a state and not to changes in vehicle design that a manufacturer chooses to undertake in response to different conditions in a section 177 state, such as different fuels or climate. The Second Circuit described those choices as marketing choices. The Second Circuit also held that the “identicality” requirement of section 177 applied only to vehicle requirements and not to fuel requirements. However, the Second Circuit held that New York had violated the lead-time requirement of section 177 by attempting to apply the standards partway into the 1995 model year and held that New York must apply its standards to an entire model year, thereby postponing the New York standards to the 1996 model year.

In Massachusetts, the vehicle manufacturers filed a motion for a preliminary injunction to temporarily enjoin the Massachusetts regulations until a full trial on the merits could be undertaken. The district court denied the preliminary injunction, and manufacturers dismissed all their claims except the lead-time claim in light of the Second Circuit’s decision on the same issues. The decision of the First Circuit Court of Appeals on the lead time differed from that of the Second Circuit, holding that Massachusetts could commence its regulations partway through the 1995 model year (American Auto Mfrs. Ass’n v. Massachusetts Dept. of Envtl. Protection, 31 F.3d 18 [1st online Cir. 1994]).

A second round of litigation under section 177 of the federal CAA occurred after California adopted memorandums of agreement (MOAs) with vehicle manufacturers to provide demonstration programs for advanced-technology ZEVs in place of the rescinded ZEV mandate for model-years 1998-2002. New York and Massachusetts contended that CARB and the vehicle manufacturers had deliberately structured the MOA response to preclude the section 177 states from adopting similar

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

ZEV programs. Massachusetts decided to adopt regulations with similar requirements as the California MOAs, which had been structured as voluntary agreements rather than regulations in California. New York decided to adhere to the original ZEV mandate for model-years 1998-2002, even though California had rescinded its version of the ZEV mandate for those years.

Vehicle manufacturer trade associations sued New York and Massachusetts in separate lawsuits. In New York, the district court held in favor of the state, holding that the ZEV mandate was not a standard subject to CAA section 209(a) preemption. That decision was then over-turned by the Second Circuit Court of Appeals, which held that the New York ZEV mandate was a preempted standard (American Auto. Mfrs. Ass’n v. Cahill, 152 F.3d 196 [2d Cir. 1998]). In Massachusetts, the district court held that the California MOAs were voluntary agreements and not standards preempted under section 209(a), and thus Massachusetts was preempted from adopting regulatory standards with similar substantive requirements. On appeal, the First Circuit initially held that it would defer to EPA’s views on whether the California MOAs were standards, but then disagreed with EPA’s opinion that the California MOAs were standards under section 209(a) and ultimately held that the Massachusetts ZEV regulations were preempted (Ass’n of Int’l Automobile Mfrs v. Commissioner, Mass. Dep’t of Envtl Protection, 208 F.3d 1 [2000]).

In summary, state adoption of the California LEV standards resulted in a series of legal controversies. The federal courts were the only available venue to resolve these issues, and the ensuing litigation took many years and large commitments of resources from both vehicle manufacturers and states. States ultimately prevailed on many of the legal issues, but the manufacturers prevailed on some. Other states that were considering adopting the LEV standards were left in limbo about the legality of adopting the LEV standards, and vehicle manufacturers and dealers subject to the LEV standards in those states that had adopted the LEV standards had to live with uncertainty and confusion about the applicable requirements for many years. A more expedient and less resource-intensive mechanism to resolve these disputes would have benefited all parties.

EPA’s Role in Implementation of the LEV Program

The role played by EPA in the adoption of the California LEV program by other states has become complicated and difficult. Section

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

177 of the CAA does not give EPA an express role in a state’s adoption process except for defining the start of a vehicle model year for the 2-year lead-time requirement. The assumption of Congress in enacting section 177 seemed to be that the waiver for California would address all relevant concerns related to economic and technological feasibility, lead time, and other issues; thus, no new issues would be raised when another state adopted California standards. As EPA explained in a letter to Congressmen John Dingell in 1991, before states used section 177 to implement the LEV standards:

Section 177 does not have an explicit requirement that the state standards adopted under this section’s authority be consistent with [the lead time and feasibility criteria of] section 202(a)…. Because a section 177 state can adopt only California standards which have received a waiver, and which are therefore consistent with section 202(a), the standards adopted by the section 177 state may also be considered consistent with section 202(a) (Reilly 1991).

EPA was nevertheless called upon to play a central role in the adoption of the LEV program in the northeastern states and to deal with many complex issues that were not anticipated by Congress or EPA. In considering CARB’s initial waiver request for the LEV standards, EPA was requested by various parties to consider the impact of adoptions by other states pursuant to section 177. EPA disclaimed any authority to consider issues raised by the attempts of other states to adopt the California standards under section 177 of the CAA (58 Fed. Reg. 4166 [1993]). EPA has, however, taken positions on a number of key issues (discussed in Chapter 3); for example, that the ZEV mandate is segregable from the LEV program, that the fleetwide NMOG average is considered a standard, and that states may adopt but not enforce a standard before the granting of a waiver to California.

Although EPA’s position is generally unofficial, it has been influential and even requested by the courts. When vehicle manufacturers sued New York, alleging that its adoption of the LEV standards violated section 177, EPA filed an amicus curiae brief in the Second Circuit Court of Appeals that had a key role in the appellate court’s reversal of the district court’s decision that the New York ZEV mandate violated section 177 (Brief for the United States as Amicus Curiae, Motor Vehicle Mfrs Ass’n v. N.Y. Dep’t of Envtl. Conservation, No. 93-7938 [2d Cir., 1993]).

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

In the Massachusetts ZEV litigation, the First Circuit Court of Appeals, faced with the issue of whether Massachusetts could adopt ZEV regulations similar to the 1996 MOA between CARB and vehicle manufactures, declined to decide the matter until EPA had issued its view under the doctrine of “primary jurisdiction,” which requires courts to defer to an administrative agency on matters within the special competence of that agency (American Automobile Mfrs Assn v. Massachusetts Dep’t of Environmental Protection, 163 F.3d 74 [1st Cir. 1988]).

EPA does have one formal opportunity to review section 177 adoptions of California standards when it approves a state SIP revision that incorporates the California standards. This process does not generally provide an effective process for resolving any controversies regarding the state’s action. First, EPA has narrow and limited authority to review and question a state action under the SIP review criteria. Second, the SIP review often occurs several years after the state action, limiting EPA’s capability to provide a timely response. For example, Massachusetts was the first state to adopt the California LEV standards, effective January 31, 1992, but EPA did not approve the SIP revision incorporating those standards for 3 years (60 Fed. Reg. 6027 [1995]). Finally, some states (for example, Vermont) have never included their adoption of California LEV standards in a SIP submittal, thus precluding any EPA oversight role via this process.

The LEV example provides evidence that, contrary to the original assumption of Congress in enacting section 177, adoptions raise some novel issues (generally of a scientific and technical nature). Most issues involve either conditions that were not considered when EPA issued a waiver to California or consistency with section 177 of the CAA. Although EPA has denied formal authority to address these issues, it has done so informally and the courts have deferred to it as the appropriate agency to do so. This example makes a strong case that EPA could have a role in the administration of section 177, just as it does for virtually every other provision of the CAA. An official EPA decision might also reduce the litigation over states' adoptions of California standards. For example, EPA decisions are challenged in the District of Columbia court of appeals as opposed to district courts where lawsuits against individual states have traditionally been litigated. The lengthy discovery and deposition processes that occur in the latter case would be reduced in a challenge to an EPA decision. Second, the courts traditionally show high deference to EPA determinations, effectively reducing the likelihood of a successful challenge.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

State Practices in Adopting California Standards

There are no federal requirements regarding state adoption of California emissions standards beyond the specifications in the CAA section 177. Adopting California mobile-source emissions standards is one of several options available to states to reach the air quality goals embodied in the NAAQS. States generally support their adoption of California standards with a state- or region-specific modeling analysis of emissions benefits. Emissions modeling also serve to quantify the LEV and LEV II program’s emissions credits that are included in the state’s SIP, and this modeling is usually a required part of the SIP analysis. Air quality modeling—for example, to assess the impact of a new regulation on ozone concentrations—is also a part of the SIP analysis. The committee did not find evidence that states analyze in-state air quality impacts or health impacts of adopting California standards (in isolation from other SIP measures). Furthermore, states typically quote and defer to the technical-feasibility and cost-analysis determination conducted by California when adopting LEV II (NYDEC 2000; MA DEP 1999). A quantification of any improvements in ozone or PM concentrations and health impacts, for example, would be useful support for adopting LEV II because they are the criteria pollutants of most concern in many nonattainment areas. The committee found one example of a nongovernmental organization that included ozone in an assessment of the health impacts of adopting LEV II standards in Connecticut (CFE 2003).

Assessment of emissions benefits is the significant technical practice carried out by states when adopting California standards. The following section discusses these assessments by northeastern states for adoption of California LEV and LEV II emissions standards. Because of the regional nature of air pollution in the Northeast, the states have a history of cooperative analysis of emissions and air quality, such as that by the Ozone Transport Commission (OTC) established by the CAA. A regional air pollution agency, Northeast States for Coordinated Air Use Management (NESCAUM), is directed by the air directors of Maine, Rhode Island, Connecticut, Vermont, New Hampshire, New York, New Jersey, and Massachusetts. NESCAUM promotes cooperation and coordination of technical and policy issues regarding air quality control among the member states. NESCAUM has assessed emissions benefits of adopting California emissions standards in support of its member states.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

Comparing the Emissions Benefits of California Versus Federal On-Road Emissions Standards in the Northeast

The northeastern states that have adopted LEV II have supported their rule-making by estimating future emissions using various generations of EPA’s MOBILE model. Table 6-14 summarizes the expected emissions benefits found by some of these analyses. The committee did not attempt to analyze the modeling practices and assumptions underlying these analyses. As discussed in Chapter 2, these models are subject to a degree of uncertainty (NRC 2000); however, they are the best tools available to regulatory agencies for assessing emissions benefits. Furthermore, many assumptions are needed to model future mobile-source emissions; for example, sales, fleet mix in future years, types of fuels, and the evolution of vehicle technology and emissions levels. The data presented in Table 6-14 and in the following comparisons serve to show the range of estimates of the emissions benefits of California over federal emissions standards. Most likely, there are significant differences between the models and assumptions used in each study; therefore, caution is needed in comparing these estimates.

The expected emissions benefits of LEV II over Tier 2 in particular have proved to be controversial. In 2003, NESCAUM estimated a 15%-HC mobile-source emission benefit in 2020 in the Northeast based on MOBILE modeling of New York, Massachusetts, and Vermont. The study also included an estimated benefit in mobile-source toxic emissions of 23%. This analysis was used by Connecticut and Rhode Island to support adopting California standards for the first time (CTDEP 2004; RIDEM 2004). Nongovernmental organizations have also used modeling in their analyses in support of state adoption of California emissions standards. The Connecticut Fund for Environment (CFE) estimated a 20%-VOC and a 11%-NOx benefit in 2025 in that state and a 33%-benefit in HAP emissions (CFE 2003). The Maryland Public Interest Research Group (PIRG) estimated a 13%-VOC benefit, a 11%-NOx benefit, and a 12-15%-HAP benefit emissions in Maryland in 2025, if the state would adopt LEV II in 2008. The Maryland Department of the Environment estimated a 5%-VOC and a 6%-NOx benefit of LEV II over Tier 2 in 2020 in Maryland (Snyder 2005).

Manufacturers argue that complying with California standards in a greater number of states comes at a greater cost, and that this cost is not outweighed by the emission benefits of LEV II over Tier 2. The Alliance

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-14 Summary of Various Estimates of Emission Reductions Analyses of Adopting California Mobile-Source Emissions Standards in the Northeasta

Analysis

Comparison

Area (Year of Benefit)

Emission Reduction Over Federal Standards (%)

HC

NOx

CO

Sierra Research, Inc. 1989

California proposed program and pre-Tier 1 federal program

Typical NESCAUM state (2010)

16.2

27.2

38.7

Pechan/EEA, Inc. 1991

LEV and Tier 1b

NESCAUM region (2015)

23-61

26-41

10-33

MA DEP 1999

LEV II (with intermediate CA MDV standards) and Tier 2

Massachusetts (2020)

20

19

17

NY DEC 2000

LEV II and Tier 2c

New York 2020

8

0

NA

NESCAUM 2003

LEV II and Tier 2d

Average between NY, MA, VT (2020)

15.3

NA

NA

NESCAUM 2005; update to 2003 data

LEV II and Tier 2d

Average between MA, NY, VT, ME (2020)

7.6

14.7

NA

 

 

Average between CT,RI, NJ (2020)

4.8

10.8

NA

aThe emissions reduction is the difference in mobile- source emissions between California and federal standards, expressed as a percentage of the federal total.

bOnly LDV <6, 000 lb of GVW; exhaust only.

cUnclear whether ZEV mandate or evaporative emissions included.

dOnly LDV <6,000 lb of GVW.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

of Automobile Manufacturers (AAM) presented its own estimates of emissions benefits and a critique of methods used by NESCAUM and other groups (Air, Inc. 2004a,b). In an evaluation of the Connecticut CFE (2003) study, an AAM contractor reported benefits of 7% for VOC, 14% for NOx and 14% for HAPs in 2025 when modeling Connecticut mobile-source emissions according to EPA guidelines (Air, Inc. 2004b).

EPA has also addressed the modeling methodologies and the benefits estimation of LEV II over Tier 2 in the Northeast. EPA addressed NESCAUM’s 2003 modeling estimates in a letter stating that NESCAUM did not follow EPA guidelines for modeling Tier 2 emissions, and this led to overstatements of the benefits of LEV II over Tier 2 (EPA 2004f). EPA stated that emissions benefits of LEV II and Tier 2 should be compared with a non-LEV II and non-Tier 2 baseline, respectively, for a realistic comparison between the two programs. Using these guidelines, EPA estimated that LEV II will provide about a 1% additional reduction in mobile-source HC over Tier 2 in 2020 (EPA 2004f; 70 Fed. Reg. 21959[2005]). NESCAUM (2004) responded to EPA concerns and performed an updated analysis of emissions benefits in the Northeast, including a separate analysis for states that only recently adopted LEV II standards. The revised emissions-benefits estimates are provided in Table 6-14. In responding to EPA, NESCAUM noted that its analysis is intended to support the conclusion that the LEV program provides additional air quality benefits and is not intended to be portrayed as a SIP analysis (NESCAUM 2004). SIP credits, including the numerical value of emissions reductions of the LEV II program, must be evaluated by each state separately in coordination with EPA.

States and NESCAUM have generally documented their analyses well, as evidenced by the ability of outside stakeholders to review and critique their practices. Although the numerical value of the emissions benefits is ultimately important in determining SIP credits, there is no required level of emissions benefits that must be met to adopt the LEV program, and adoption and SIP regulatory processes are usually separate. All of these analyses are presented in terms of additional percentage reductions. Emissions reductions apparently were not translated into estimates of health or environmental benefits. This committee makes no judgment on an appropriate level of emissions benefits (over a similar federal program) to support adoption of a California emission standard. A comparison of benefits and costs for such a decision is in the realm of policy and outside this committee’s charge.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

Economic Impact Assessment by Opt-in States

Each state is subject to certain requirements for each rule-making. New York, for example, prepared a regulatory impact statement and a job impact statement for adoption of California regulations. The majority of these requirements concern economic impacts. The states that are adopting the California LEV II standards rely for the most part on CARB’s ex ante cost estimates as the measure of projected costs of the program. They do not attempt to measure any costs beyond the consumer costs estimated by CARB. For example, states do not appear to measure the cost of program administration, the distribution or dealer costs, or the costs of enforcement of the program. States do not discuss the potential infrastructure costs that might be needed for the ZEV component of the LEV II program. Massachusetts, for example, stated that there will be no significant economic effects on dealers. It suggested, however, that dealers will need to incur more training costs for mechanics because of additional types of vehicles, but these costs are assumed to be recouped through increased sales of vehicles, such as the PZEVs and the ATPZEVs (MADEP 1999).

In an analysis by New York, the state argued that the ZEV requirements are not expected to have any effect on dealers and that any change in required paperwork will not be substantial. Using the same argument as Massachusetts, New York stated that there must be additional mechanic training but that this will generate new jobs for the region. However, fewer vehicles of other types will be sold, and the mix of services needed will change for mechanics. The costs of retraining represents costs to dealers or car buyers, depending on how the costs are distributed. On the ZEV mandate, Maryland, one of the states that decided against adopting the LEV II standards, stated that it had identified substantial infrastructure costs associated with the ZEV component of LEV II (Snyder 2005).

There is little discussion from the states or in the NESCAUM analysis of the LEV II program about the potential distribution issues or pricing policies for LEVs. The auto companies argue that there are sales issues, especially at the border of the LEV II states. Often, dealers near state borders swap vehicles over state lines, potentially complicating compliance with the standards for the automakers. For that reason, at least one automaker (J. German, Honda, personal commun., May 18, 2005) argued that it designs vehicles to meet both Tier 2 and LEV II standards when possible. As noted in Chapter 5, however, cost data are

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

often difficult to obtain, thus limiting the scope of any state economic impact analysis.

An additional problem is that the prices of an entire fleet in a region might require adjustment to sell a vehicle fleet that meets the emissions standards. Pricing this fleet at the cost of the emissions controls might not result in sales. In that case, subsidies of certain vehicles might be necessary, and the costs of bringing the fleet to market might change. There is little discussion of any of these issues in economic impact analyses of LEV standards by California and opt-in states. The committee heard some evidence of a proposed Northeast-wide NMOG fleet average that manufacturers could use to certify vehicles. This proposal might provide more flexibility to the manufacturers in selling vehicles that meet the standard. Such flexibility on sales and distribution might ease the economic burden for manufacturers and dealers and decrease the limitations of consumer choice. The committee encourages such flexibility, provided air quality is not compromised.

CALIFORNIA MOTOR VEHICLE GREENHOUSE GAS STANDARDS

Legislative Mandate

The California legislature in 2002 concluded that the effects of global warming in California would be substantial. The Pavley bill (California AB 1493, Feb. 23, 2001) in particular found that global-warming impacts on the state included: potential reductions in the state’s water supply, adverse health effects from increases in air pollution caused by higher temperatures, adverse impacts on agriculture caused by impacts on water supplies and increases in pestilence outbreaks, increases in wildfires, and potential damage to the state’s coastlines and ocean ecosystems. In response, the legislature passed and Governor Davis signed into law the Pavely bill. This legislation directed CARB to develop and issue greenhouse gas (GHG) emissions standards for LDVs, using its authority to set its own mobile-source emissions standards (CAA section 209). The legislature directed CARB to “develop and adopt regulations that achieved the maximum feasible and cost-effective reduction of greenhouse gases from motor vehicles.” The Pavey bill focuses on LDVs because approximately 40% of GHG emissions in the state are estimated to come from this source.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

TABLE 6-15 CO2 Equivalent Emissions Standards for Model-Years 2009 through 2016

 

Year

CO2 Equivalent Emissions Standard by Vehicle Category (g/mi)

Passenger Cars and Small Trucks/SUVs

Large Trucks/SUVs

Near-term

2009

323

439

 

2010

301

420

 

2011

267

390

 

2012

233

361

Mid-term

2013

227

355

 

2014

222

350

 

2015

213

341

 

2016

205

332

Source: CARB 2004d.

Proposed Regulation

In response, CARB (2004c) proposed a set of standards in its staff report; these standards were approved and adopted by CARB on September 23, 2004. Table 6-15 displays the proposed standards, which are given in grams per mile of CO2 equivalent.11 The proposal recognized four sources of motor vehicle GHG emissions: tailpipe emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions; CO2 emissions due to operating the vehicle air conditioning system; hydrofluorocarbon (HFC) emissions from the air conditioning system; and upstream GHG emissions associated with the production of fuels. The CO2 equivalent standards are incorporated into the existing LEV program and, like existing LEV II standards, there is a separate fleet average for passenger cars and small trucks/SUVs and large trucks/SUVs.

11  

Emissions of other GHGs are translated into estimates of the equivalent amount of CO2 by use of global warming potential (GWP). Because the atmospheric lifetimes of other GHGs are different from CO2, a GWP depends on the time horizon. If a 100-year time horizon is used, CH4 has a GWP of 23, N2O has a GWP of 296, HFC-134a has a GWP of 1,300, HFC-152a (a possible replacement for HFC-134a) has a GWP of 1,300. The 100-year time horizon is recommended by the Intergovernmental Panel of Climate Change and CARB.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×
Scientific and Technical Analysis

The CARB staff report (2004c) includes an assessment of the technology and fuels that could help meet the standards, the level of reductions that could be achieved, and the costs. The CARB assessment was based on vehicle simulation and cost analysis of GHG emissions reductions contained in a report done for the Northeast States Center for a Clean Air Future (NESCCAF 2004). NESCCAF (2004) predicted the GHG emissions impacts of various technology combinations for five types of vehicles (small car, large car, minivan, small truck, and large truck) by using a model that estimates operating characteristics and emissions for different motor vehicle designs. NESCCAF (2004) also provided cost estimates for the various technology combinations, including available technologies and technologies that had been demonstrated in prototype form.

CARB (2004d) estimated that the near-term (2009-2012) standards would result in a 22% reduction in GHG emissions compared with the 2002 fleet, and the mid-term (2013-2016) standards would decrease fleet emissions by 30%. These estimates translate into an 88,000 ton/day reduction in CO2-equivalent emissions by 2020 and a 155,000 ton/day reduction by 2030 (CARB 2004d). Table 6-16 shows the estimated fleetwide incremental costs of controls to meet these standards developed by CARB. Some portion of the cost of reductions in CO2 can be recouped in

TABLE 6-16 Average Cost of Control

 

Year

Average Cost of Control

Passenger Cars, Small Trucks, and SUVs

Large Trucks and SUVs

Near-term

2009

17

36

 

2010

58

85

 

2011

230

176

 

2012

367

277

Mid-term

2013

504

434

 

2014

609

581

 

2015

836

804

 

2016

1,064

1,029

Source: CARB 2004d.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

fuel savings over time. CARB asserts that nearly all technology combinations will result in reductions in lifetime operating costs that exceed retail price of the technology, assuming a fuel cost of $1.74 per gallon; cost recovery time would presumably be smaller at higher gasoline prices. For example, CARB (2004d) looked at the potential increase in monthly payments over a 5-year vehicle loan versus the monthly decrease in operating costs and concluded that the proposed standards would result in a monthly savings of $3.50 to $7.00.

Manufacturers and others have submitted comments critical of CARB’s analysis (CARB 2005f). CARB’s cost estimates are disputed by an analysis performed by Sierra Research for the Alliance of Automobile Manufacturers (Sierra Research 2004), which concluded that average compliance costs would be approximately $3,000 per vehicle, assuming nationwide compliance with the CARB standards, and higher than $3,000 if separate vehicles are produced for states that enforce the California standards. Sierra Research also argued that the increased vehicle prices would decrease the sales of new vehicles, slowing the introduction of cleaner vehicles into the fleet, and that lower operating costs would result in vehicle owners driving more, thus increasing emissions.

Another objection to the standards is that California LDV emissions are a small fraction of the global totals and will have no discernable effect on global climate change (CARB 2004c). CARB pointed out, however, that its GHG standards represent a “no regrets” policy (reducing emissions while providing a net cost savings to vehicle owners) and that the state’s action will prompt other states and countries to follow course (CARB 2004c).

Opt-in States

Recent state actions and statements also reflect a growing desire by states to reduce GHG emissions. Massachusetts, New York, New Jersey, Connecticut, Rhode Island, Vermont, and Maine have amended their prior adoption of the LEV II program to include the California GHG emissions standards. In addition, Washington state recently adopted the LEV II program contingent on Oregon’s adoption. Oregon has adopted temporary rules on the LEV II program and is scheduled to propose permanent rules in the summer of 2006. Neither state has areas in nonattainment of the 1-hr or 8-hr ozone standard. Both states are focusing on the GHG emission-reduction benefits of the California program (Office of the Governor of Washington 2004; State of Oregon 2004).

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
×

Legal and Administrative Status of Greenhouse Gas Initiative

CARB approved the GHG standards in September 2004, and the final rule-making package was approved by California’s Office of Administrative Law on September 15, 2005. The standards face major challenges in terms of obtaining a waiver from EPA and from lawsuits filed by automakers. A primary objection raised by automakers is that, because most reductions in GHG emissions are from decreases in CO2 emissions due to improved fuel economy, the GHG standards are fuel economy standards, which are preempted by federal laws and regulations mandating uniform, nationwide standards for fuel economy. That objection will be one of the primary arguments made by plaintiffs in the lawsuit, Central Valley Chrysler et al. v. Witherspoon, which is scheduled to begin trial in the Federal District Court in late 2006.

CONCLUSIONS

The history of LDV regulation provides insights into how EPA and CARB set emissions standards and how other states adopt standards. EPA and CARB’s present-day LDV emissions standards integrate fuel and emissions limits, certification flexibility, and, in CARB’s case, a mandate for promoting advanced-technology vehicles. The following conclusions are drawn from the information presented in this chapter on the practices and issues related to LDV emissions standards.

  • CARB and EPA analyses of their emissions standards are found in CARB’s staff paper and EPA’s regulatory impact analysis, respectively. Both documents include a technical feasibility assessment, emissions impacts analysis, engineering cost assessments, and cost-effectiveness estimates. For major rules, such as the Tier 2 LDV regulations, EPA is required to conduct a health benefits assessment to compare with total costs. CARB does not consider public health benefits directly in its regulatory analysis of emissions standards because it uses its proposed standards to attain health-based NAAQS, which EPA has already assessed for public health benefits.

  • The majority of available cost estimates of emissions standards are for LDVs, but these estimates vary substantially and are uncertain. It is difficult to determine what parties bear what fraction of the costs of emissions standards. Manufacturers closely guard cost and pricing data to avoid placing themselves at a competitive disadvantage.

Suggested Citation:"6 Light-Duty-Vehicle Emissions Standards." National Research Council. 2006. State and Federal Standards for Mobile-Source Emissions. Washington, DC: The National Academies Press. doi: 10.17226/11586.
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  • With the LEV program, California has used its authority as Congress envisioned: to implement more aggressive measures than the rest of the country and to serve as a laboratory for technological innovation. There have been successes, such as CARB’s early recognition of the need to couple fuel composition with emissions control, and failures, such as the promotion of widespread use of electric vehicles.

  • As a rationale for adopting California LDV standards, some states expect that California will continue to reduce standards earlier than the federal program. Some states have also adopted or expressed interest in adopting the California GHG emissions standards.

  • To date, CAA section 177 authority has been used primarily by various northeastern states to adopt California LDV standards. Manufacturers of mobile sources have raised objections to the adoption of California standards by other states. Up to this point, adopting states and manufacturers have turned to the courts to resolve their technical and legal disputes when direct negotiations have failed. Although EPA is an appropriate entity to comment on some of these disputes, it has no authority over states’ adoption decisions.

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Emissions from mobile sources contribute significantly to air pollution in the United States. Such sources include cars and light- and heavy-duty trucks; diesel-powered cranes, bulldozers, and tractors; and equipment such as lawnmowers that run on small gasoline engines. The role of state versus federal government in establishing mobile-source emissions standards is an important environmental management issue. With this in mind, Congress called on EPA to arrange an independent study of the practices and procedures by which California develops separate emissions standards from the federal government and other states choose to adopt the California standards. The report provides an assessment of the scientific and technical procedures used by states to develop or adopt different emissions standards and a comparison of those policies and practices with those used by EPA. It also considers the impacts of state emissions standards on various factors including compliance costs and emissions. The report concludes that, despite the substantial progress in reducing emissions from mobile sources nationwide, more needs to be done to attain federal air-quality standards in many parts of the country. Additionally, California should continue its pioneering role in setting emissions standards for cars, trucks, and off-road equipment.

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