Policy Options for Reducing Energy Use and Greenhouse Gas Emissions from U.S. Transportation Special Report 307 (2011) / Chapter Skim
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2 U.S. Transportation Today
2 U.S. Transportation Today
Pages 53-94
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From page 53... ...
2 U.S. Transportation Today Transportation -- the movement of people and goods -- is central to economic activity and to the daily lives of Americans.
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Department of Transportation began releasing data from the 2009 National Household Travel Survey (NHTS)
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personal transportation The transportation of people accounts for about two-thirds of total transportation energy consumption. Thus, knowledge of the current characteristics of this activity and the factors driving it is helpful in gaining insight into where transportation energy use and emissions may be heading.
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An NHTS has been conducted every 5 to 8 years since 1969.2 Although the NHTS was most recently conducted in 2009, its final results were not released in time for this report, which refers to the 2001 NHTS results instead. 2 The name of this travel survey has changed over the years, but all previous versions are referred to in this report as the National Household Travel Survey.
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From page 57... ...
For the year as a whole, the average household (consisting of 2.6 persons) made about 3,600 person trips and traveled approximately 35,200 person miles.
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and thus in projecting transportation energy use and emissions. In making VMT projections for the U.S.
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In 2001 commuting accounted for just 16 percent of all household person trips and for approximately 19 percent of household person miles traveled. In contrast, "household-serving" travel -- consisting of trips for shopping, errands, chauffeuring family members, and so forth -- accounted for the largest share of travel, representing 44 percent of person trips and one-third of all household person miles.
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table 2-1 Person Trips per Household and Person Miles Traveled per Household, 1983 and 2001, Based on NHTS Data Person Trips per Household Average Annual Person Miles Traveled per Household Percent Percent Percent Percent Share Share Percent Share Share Percent of 1983 of 2001 Change Change of 1983 of 2001 Change Change Trip Purpose 1983 2001 Trips Trips 1983–2001 1983–2001 1983 2001 PMT/HH PMT/HH 1983–2001 1983–2001 To or from work 537 565 20 16 28 5 4,586 6,706 20 19 2,120 46 (commute) Work-related 62 109 2 3 47 76 1,354 2,987 6 8 1,633 121 business Shopping 474 707 18 20 233 49 2,567 4,887 11 14 2,320 90 All other family 456 863 17 24 407 89 3,311 6,671 15 19 3,360 101 and personal business School and 310 351 12 10 41 13 1,522 2,060 7 6 538 35 church Social and 728 952 28 27 224 31 8,964 10,586 39 30 1,622 18 recreational Other 61 30 2 1 500 1,216 2 3 716 143 −31 −51 All purposes 2,628 3,581 100 100 953 36 22,802 35,244 100 100 12,442 55 Noncommute 2,091 3,016 80 84 925 44 18,216 28,538 80 81 10,322 57 trips only NOTE: HH = household; PMT = person miles of travel.
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. Whether measured by the number of person trips or the number of person miles traveled, the vast majority of household travel is by personal vehicle.
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goods transportation The principal modes used to transport goods within the United States are truck, rail, barge, airplane, and pipeline.8 The transportation of goods accounts for approximately 28 percent of domestic transportation energy use and for about the same percentage of U.S. transport-related CO2 emissions.
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SOURCE: Bureau of Transportation Statistics and Transportation Commodity Flow Survey, U.S. Bureau of the Census, December 2009.
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Weight Classes Typical Vehicle Class 8 33,001 or greater Dump Cement Heavy tandem conventional 26,001–33,000 Class 7 Fuel Recycling Medium conventional 19,501–26,000 Class 6 Stake Beverage Single-axle van 16,001–19,500 Class 5 14,001–16,000 Class 4 Short-nose Cab forward Walk-in van 10,001–14,000 Class 3 conventional with van body with van body figure 2-1 Truck categories and typical vehicles in each category. Gross vehicle weight includes weight of empty vehicle plus payload.
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From page 65... ...
Truck VMT Trucks Trucks per Truck Total for all trucks 145,172 100.0 5,520,000 100.0 26,299 Trucks with annual miles >50,000 87,500 60.3 920,000 16.7 95,109 Basic Body Type Single unit 51,158 35.2 3,873,000 70.2 13,209 Single-unit combinations 3,843 2.6 258,000 4.7 14,895 Tractor–trailer combinations 90,170 62.1 1,421,000 25.7 63,455 Range of Operation (miles) <100 62,000 42.7 3,620,000 65.6 17,127 101–200 11,800 8.1 244,000 4.4 48,361 201–500 17,520 12.1 232,000 4.2 75,517 >500 26,706 18.4 293,000 5.3 91,147 Not reported 25,000 17.2 716,000 13.0 34,916 Truck Size (excludes personal vehicles)
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From page 66... ...
427,065 524,223 23 −52 Miles of road owned 196,479 94,082 Revenue ton-miles per mile of road owned 3,892,574 18,890,287 385 Revenue ton-miles per car mile 26 48 87 Revenue tons per train mile 1,791 3,390 89 Freight cars per train 70 71 1 Fuel consumed in freight service 3,545 3,886 10 (million gallons) Ton-miles per gallon 216 457 112 SOURCE: Bureau of Transportation Statistics, National Transportation Statistics, 2010, Appendix D
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From page 67... ...
During the same time that containerization emerged, supply chain management also took on importance in freight transportation, influencing the total volume of shipments and average shipment size and distance.11 Thirty years ago, most businesses operated what were then known as "push" supply chains. Suppliers delivered materials to a manufacturer, who pushed products to a distributor or retailer and then to the customer.
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From page 68... ...
Energy Performance of Major Transport Modes There are many modes of passenger and freight transportation, but only a few of them account for most of the sector's energy use and GHG emissions. As noted in Chapter 1, three modes -- light-duty vehicles, medium- and heavy-duty trucks, and commercial airlines -- together account for 93 percent of the sector's domestic energy use.
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chapter, along with freight rail, public transit, and intercity passenger rail, which are often portrayed as the main modal alternatives. energy characteristics of light-duty vehicles As noted earlier, light-duty motor vehicles -- passenger cars and light trucks -- account for the largest share of transportation activity, energy use, and GHG emissions.
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More recently, the share of engines with variable valve timing exceeded 75 percent by 2008, and cars equipped with turbochargers and gasoline–electric hybrid propulsion systems have become more common. Increasing Fuel Economy Potential Most of these trends in power train characteristics tended to improve the energy-efficiency potential of light-duty vehicles.13 As the top portion of 12 Light trucks consist of three distinct types of vehicles: pickup trucks, sport utility vehicles (SUVs)
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table 2-6 Changes in Power Train Characteristics of Light-Duty Vehicles over Time Drivetrain Transmission Other Power Train Characteristics Model Year FWD 4WD Manual Auto Lockup CVT PFI Multivalve VVT Turbo Hybrid 1975 5.3 3.3 23.2 4.1 1980 25.0 4.9 35.4 17.8 5.2 1985 47.8 9.3 26.5 54.4 18.2 1990 63.8 10.1 22.2 71.2 70.8 1995 57.6 16.2 17.9 80.7 91.6 35.6 2000 55.5 20.2 9.7 89.5 99.8 44.8 15.0 1.3 2005 53.0 26.8 6.2 91.4 2.3 99.7 65.6 45.8 1.7 1.1 2008 53.3 27.8 6.7 85.5 7.8 97.6 77.4 57.7 2.5 2.5 NOTE: FWD = front-wheel drive; 4WD = four-wheel drive; auto lockup = automatic transmission with lockup clutch; CVT = continuously variable transmission; PFI = port fuel injection; multivalve = engine with more than two valves per cylinder; VVT = variable valve timing.
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. Fuel economy improvement potential grew more rapidly during the former period than during the latter
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. However, the rate of growth in fuel economy improvement substantially exceeded the rate of growth in fuel economy improvement potential during the former period, while during the latter period it lagged substantially (in the case of test measures of fuel economy)
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In 2006 these vehicles consumed about 40 billion gallons of fuel, representing about 19 percent of total transportation energy use. Generalizations concerning energy characteristics and trends are more difficult to make for freight trucks than for passenger cars because they are produced in such a wide range of sizes and have such a wide range of functions.
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Single-unit truck 1,583 1,480 0.93 Combination truck 9,201 12,944 1.41 Average miles traveled per gallon 5.4 5.9 1.09 of fuel consumed Single-unit truck 5.8 8.2 1.41 Combination truck 5.3 5.1 0.96 Number of trucks registered 5,790,653 9,919,007 1.52 Single-unit truck 4,373,784 75.5 6,649,337 75.4 1.52 Combination truck 1,416,869 24.5 2,169,670 24.6 1.53 Average miles traveled per vehicle 18,736 25,290 1.35 Single-unit truck 9,103 12,081 1.33 Combination truck 48,472 65,773 1.36 Ton-miles (millions) 629,675 1,294,492 2.06 Vehicle miles (millions)
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airline energy characteristics Passenger airplanes are the third-largest user of transportation energy and emitter of GHGs domestically. These aircraft are but one component of the total U.S.
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In 2006, each aircraft averaged 2.9 million gallons of fuel burned and produced 120 million revenue passenger miles, in addition to moving freight in its cargo compartment. Yet, as shown in Table 2-9, the amount of fuel, or energy, used per passenger mile has declined by 70 percent because of large gains in the airline industry's economic efficiency.
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However, they account for less than 9 percent of the energy used for transporting freight and about 2 percent of transportation energy consumption in total.16 Railroads, for the most part in the movement of bulk cargoes, consume about 4 billion gallons of diesel fuel annually, a number that has remained fairly constant 16 Rail freight energy data in this section are obtained from the Transportation Energy Data Book 29. http://cta.ornl.gov/data/tedb29/Edition29_Full_Doc.pdf.
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Rail freight averages more than 400 ton-miles per gallon of diesel fuel, compared with an average of about 70 ton-miles per gallon for combination trucks. Since 1980, the number of ton-miles of freight that railroads can generate by using 1 gallon of fuel has grown by 96 percent.
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The rail freight industry has established a goal of improving its ratio of freight carried to fuel consumption by 10 percent, from an average of 400 to 440 ton-miles per gallon.17 Further advances in the energy efficiency of freight rail may be important from the standpoint of rail profitability, but the effect on total transportation energy consumption is likely to be relatively small. If 2 billion ton-miles of freight are moved by rail, the fuel efficiency gains would save less than 500,000 gallons of diesel fuel, or the equivalent of less than 5 days' worth of the fuel consumed by the nation's freight trucks.
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Although the figures indicate that transit's role in total passenger travel is small nationally compared with automobiles, the role played by public transport in some locations -- and the role it might play in the future -- warrants attention. Transit is generally thought of as highly energy efficient, and an explanation of why the data in Table 2-10 show that the average transit bus used 27 percent more energy per passenger mile than the average passenger car in 2006 is warranted.
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.b The more than 80,000 transit buses in the public transit fleet accounted for about 60 percent of all passenger trips by transit. Heavy and light rail transit carried about 3.3 billion passengers in 2006 for 17.5 billion passenger miles.
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Forty metropolitan areas have populations of 1 to 5 million. table 2-10 Energy Use per Passenger Mile by Personal Transport Modes, 2006 Btu per Percent Relative Mode Passenger Mile to Passenger Cars Transit Mode Transit bus 4,348 127 Transit rail 2,521 73 Commuter rail 2,656 77 Other Personal Transport Mode Passenger car 3,437 100 Domestic air carrier 2,995 87 SOURCE: Transportation Energy Data Book, Edition 29, Table 2.12.
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From page 84... ...
Intercity rail, however, serves only about 500 stations nationwide and carries 5.5 billion passenger miles per year, which is less than 1 percent of total passenger miles. But in at least one corridor -- the Northeast Corridor, running from Boston through New York City to Washington, D.C. -- Amtrak handles a significant share of total traffic.
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These tracks are designed to accommodate freight trains, greatly limiting the speeds at which passenger trains can operate as well as the number of passenger trains that can be accommodated. In recent years interest in developing high-speed passenger rail service in the United States has been growing.
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CBO revealed how this measure was too narrow for the purpose of analyzing net energy effects from policy choices about transportation investments. CBO developed a framework for evaluating energy performance that considers the various interrelated components and sources of transportation energy use.
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Similar calculations could be made for the energy performance of freight rail that involves truck connections to and from freight rail terminals. In analyzing the energy implications of enhancements to a particular transportation service (such as providing more frequent bus service)
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Considerations Affecting the Adoption of Fuel-Saving and GHG-Reducing Technologies In 2005, the amount of fuel used by typical transportation vehicles ranged from 541 gallons per year for the average passenger car to 2.4 million gallons per year for the average commercial aircraft (Table 2-11)
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Passenger car 12,427 541 Taxicab 58,333 3,523 Light truck 11,100 686 Single-unit truck 12,400 1,414 Combination truck 68,800 11,698 Transit bus 30,190 6,462 Rail freight locomotive 69,879 184,374 Commercial aircraft 1,003,000 2,384,924 14 to 31 percent of total operating costs for the 21 major U.S. air carriers, from 11 to 26 percent of total operating costs for the Class I railroads, and from 17 to 31 percent of the total operating costs (less rentals and purchased transportation)
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Although carriers may try to pass the higher fuel costs on to their customers, there will be competitive incentives to seek means of reducing these costs (and gaining market share) by reducing the energy intensity of their services.
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The average taxicab is the average private automobile weighs about 3,000 pounds.a Therefore, it is not surprising that the average private automobile used 541 gallons per year in 2005 while the average taxicab used 3,523 gallons. Higher fuel prices will have a greater impact on taxicab fuel costs than they will on fuel costs for the typical automobile.
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From page 92... ...
There also has been a long-term shift toward more energy-intensive transport modes, particularly from walking and public transportation to cars and light trucks for passengers and from freight rail to truck for goods movement. Therefore, despite the improvements in vehicle energy efficiency, transport energy use has grown, and since nearly all energy used by transportation has been petroleum-based, GHG emissions have grown roughly in parallel.
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From page 93... ...
Figure 2-5 shows that since 1970, slight declines in miles traveled by cars and trucks have occurred only during periods of economic recession. The general upward trend in motor vehicle travel has been relentless and largely reflective of population growth and the many economic transactions and social interactions that increased mobility
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The challenge will be in retaining these economic and social benefits, even as the transportation sector and its energy sources undergo substantial change. References abbreviations AAR Association of American Railroads APTA American Public Transportation Association CBO Congressional Budget Office AAR.
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