A description is given in Chapter 1 of how, despite widespread dissatisfaction with aspects of present federal truck size and weight regulations, recent efforts at reform have not been successful. Three impediments that may account for this difficulty are identified in Chapter 2. First, analyses have not started with clear definitions of the objectives of reform. Second, evaluation is not integrated with the management of the regulatory program, so no established mechanisms exist for measuring performance, considering proposed revisions, or establishing policy direction. Third, certain important effects of the regulations on highway costs are poorly understood or have not been assessed with the most appropriate methods. As described in Chapter 2, with present knowledge it is not possible to carry out a complete and satisfactory prospective evaluation of all the consequences of size and weight regulatory alternatives.
Proposals for improvements to the regulations should take these impediments into account. Therefore, institutional arrangements for overseeing change in federal regulation in a way that would increase the likelihood of beneficial outcomes and for remedying deficiencies in knowledge about the costs and benefits of the regulations are examined in this chapter. The need for an independent organization chartered to conduct the essential regulatory support functions of monitoring, evaluation, research, and oversight is described. With these new capabilities in place, the federal government and the states would be in a better position to manage the regulatory program, and policy options would be opened up that otherwise would be impractical.
Proposals for changes in federal truck size and weight regulations are also outlined. Implementation of any of these proposals would make use of the new evaluation and research organization’s capabilities. The proposals include the recommendations of TRB Special Report 225, Truck Weight Limits: Issues and Options (TRB 1990a); a modified version of the Truck Weight Limits proposal; and a proposal for more liberal federal standards that has similarities with cer-
tain industry proposals and with practices in other countries. Finally, two methods of regulating truck use that depart from conventional federal regulatory practice are described: performance standards and greater use of pricing incentives to manage truck traffic.
In its direction for the present study, Congress asked TRB to review the merits of the Truck Weight Limits recommendations. The second proposal, the modified version of Truck Weight Limits, would share most of the objectives of the Truck Weight Limits proposal, but would respond to some of the criticisms the original proposal received when the study was published. The third proposal would represent a federal initiative to move U.S. size and weight policy in the direction that the evaluations of past size and weight studies imply might yield the greatest benefits. The TRB and DOT studies reach generally optimistic conclusions about the potential benefits of liberalizing the regulations, but as argued in Chapter 2, their estimates contain large uncertainties and some likely errors. The risk from these uncertainties becomes greater as the magnitude of the proposed change in regulations becomes greater. Therefore, this last proposal cannot be evaluated adequately without improved information. None of these regulatory packages is presented here as the optimal federal size and weight regulatory scheme. In Chapter 5, a description is given of how the impacts of their provisions should be subject to evaluation, making use of the organizational arrangements described in the first section of this chapter.
Performance standards and pricing are not presented as alternatives to the first three proposals. Rather, they are regulatory techniques that can be combined with any proposal to magnify its effectiveness.
INSTITUTIONAL ARRANGEMENTS TO ALLOW FACT-BASED REGULATION
Effective federal regulation of truck size and weight and effective federal oversight of state administration of federal regulations require monitoring, evaluation on an ongoing basis, and research. The federal government does not have the necessary capabilities today. Organizational arrangements that would be suited to fulfilling these requirements are outlined in this section. The committee’s recommendations regarding the establishment of new arrangements are presented in Chapter 5. The four subsections below address in turn specification of the necessary federal oversight activities; the matters of funding, personnel, and legislative authorization; organizations that could serve as models for the needed arrangements; and the conduct of pilot studies, which would be a useful evaluation technique.
Essential Research, Evaluation, and Oversight Functions
In Chapter 2, it is argued that regulation ideally is an ongoing process in which research and prospective analysis form the basis for development and enactment of regulations, the effects of regulations are systematically monitored, and the results of monitoring suggest needs and opportunities for improved regulation. Historically, in the case of size and weight regulation, this cycle has not functioned. Research, evaluation, and monitoring have been sporadic and unsystematic and have not been closely linked to revision of the regulations.
Specifically, the following activities would be required to institutionalize a process of ongoing improvement of federal regulations:
The conduct of research studies addressing fundamental questions about the relationship of vehicle characteristics to highway transport costs, and pilot studies of proposed new vehicles and related operating practices. The research agenda should be determined in a process open to proposals from the private sector, the states, and others. The following are examples of fundamental research questions, suggested by the gaps in knowledge identified in Chapter 2:
Effects of truck performance on traffic flow and pollutant emissions on urban roads;
Effects of configuration and other design features on accident involvement rates of existing trucks; and
Bridge costs of truck traffic and best practices for managing bridge systems, taking into account safety, bridge construction and maintenance costs, and highway transport costs.
The importance of pilot studies is described later in the chapter.
Monitoring and program evaluation on an ongoing basis. Program evaluations would gauge whether practices intended to control accident risks and to operate highways efficiently (including size and weight regulations) were functioning as intended. Monitoring here means systematic observation to maintain up-to-date information in three areas: commercial motor vehicle traffic volumes and the distributions of dimensions and configurations of vehicles; the administration of regulations, including enforcement and fees; and costs of commercial motor vehicle traffic to highway agencies and to the public, including accidents and infrastructure costs. The design of data collection systems for monitoring depends on the specific objectives, but most needs would require data collection using scientifically designed sampling techniques. Observing the consequences of changes in federal regulations would be an important monitoring and evalua-
tion task. Monitoring activities could be joint federal–state efforts, but for purposes of federal regulation, ensuring the reliability and adequacy of information would be a federal responsibility.
Support for state implementation of federal size and weight regulations. Oversight is a necessary function under present federal law. In addition, a federally supervised permitting program, which is an element of the regulatory options described later in this chapter, would require procedures for reviewing state permitting programs to certify that they were meeting federal requirements and for developing model regulations and model permitting programs as guidance to the states.
The scope of these activities is well beyond the current federal commitment to evaluating the performance of federal regulations and overseeing their application by the states, and does not align with the competencies of any existing federal agency. To implement the federally supervised permitting program, it would be necessary to create an organizational home for these oversight functions. The most suitable arrangement would be an independent organization with a permanent charter to evaluate commercial motor vehicle performance and the effects of size and weight regulation. This organization, which might be called the Commercial Traffic Effects Institute, would be chartered to carry out a program of development of federal size and weight regulations and related highway management practices, recommend regulatory changes, evaluate the results of implementation of new regulations, and support state implementation of federal regulations. The Institute would be authorized to enter into agreements with private-sector entities to conduct joint programs of data collection, research, and evaluation.
The Institute would use the results of pilot studies and of its research to formulate recommendations for changes in federal regulations when it had sound evidence that the changes would further congressionally defined objectives. It would recommend adjustments when its monitoring and program evaluations revealed that regulations were not working as intended or when innovations in truck or highway technology created conditions not envisioned when the regulations were enacted. The Institute also would make recommendations to harmonize areas of federal highway policy related to size and weight regulation and to truck costs, including practices and requirements regarding safety regulation, enforcement, infrastructure design and management, and user fees.
A successful organization such as that described above would come to be seen by industry, state governments, and others as a means to implement ideas about more efficient highway management and truck regulation. That such an opportunity hardly exists today is one of the most unsatisfactory aspects of the existing regulatory arrangement. Industry would be expected to bring proposals to the Institute, especially if industry were involved in the organization’s structure. Numerous examples may be cited of good-faith proposals from industry and the states for modifications to federal standards that never received due consideration, in part because no mechanism existed for evaluating them. Facilitating innovation would require processes perceived to be open, objective, and scientifically sound; access to adequate resources and the authority to enter into agreements for the conduct of evaluations; and a formal, defined relationship between research and evaluation results and regulatory decisions.
Authorization, Funding, and Personnel
Congressional action would be necessary to create the Institute. Legislation would specify its charge; its powers and responsibilities; and its governance, including the nature of state and private-sector involvement.
Creation of the Institute, together with introduction of the federally supervised state permitting program discussed later in this chapter, would correct an anomaly in the manner in which federal size and weight regulation is administered. Whereas other spheres of federal regulation are overseen by executive-branch agencies with established, ongoing responsibility for regulatory development, federal size and weight regulations have been established almost exclusively by direct legislation. DOT has certain rulemaking responsibilities, but their scope is restricted (for example, to definitional questions). In other areas of regulation, the responsible executive agency routinely carries out evaluations because it has the authority to make adjustments as necessary to respond to emerging problems and changing technology. Examples are the Federal Motor Carrier Safety Administration (FMCSA), National Highway Traffic Safety Administration (NHTSA), Environmental Protection Agency (EPA), and Occupational Safety and Health Administration (OSHA). However, the limited range of executive agency responsibility has discouraged evaluation of size and weight regulations. It is worth noting that the ICC, in the first federal truck size and weight study in 1941, foresaw problems inherent in direct legislative standards setting:
The problems to be faced in the exercise of Federal powers in this regard [size and weight regulation] do not permit of detailed statutory expression of precise standards generally and universally applicable; there obviously is need for administrative determination in the light of the facts of given situations as related to the declared standard of Congress that commerce be not unreasonably burdened (ICC 1941, 26).
The solution proposed by the ICC, that Congress give it authority to set standards administratively for particular geographic or commercial circumstances, might have proven too cumbersome, and Congress did not act at the time on the ICC’s recommendations. The state permitting program discussed later, under federal supervision and with support of the Institute, is an alternative that would avoid the problems with direct legislative standards setting identified by the ICC, make use of the technical competence and local knowledge of the state governments for selection of detailed standards within a range of alternatives, and ensure that federal interests are safeguarded. Congress could retain its historical practice of establishing regulations directly by legislation rather than delegating standards setting to an executive agency, but states would have flexibility within a federally defined range, and Congress would rely on the formal mechanism it had created in the Institute for evaluating and proposing regulatory changes.
Past studies of the use of research in administering federal regulations have observed that a conflict exists between regulation and evaluation. The regulatory agency’s goals are to see that rules are promulgated and defended from attacks; research may be perceived as lending credence to doubt about the aims and effectiveness of the rules and so as a source of delays and challenges. (TRB 1997, 28–29; NRC 1991, 15) One way to prevent this conflict from interfering with research would be to create an independent body charged with improving the performance of the regulations. This body’s research results and recommendations would be formally linked to the regulatory process, but it would not have direct regulatory or enforcement responsibilities.
The charge to the Institute would be critical to its success. A vague charge would be a handicap; as pointed out in Chapter 2, the absence of clear, congressionally defined objectives for reform has reduced the value of past DOT truck size and weight studies and hindered progress toward better regulations. However, if the Institute’s charge specified practical goals and directed it to find means of attaining them and of
overcoming any obstacles, the Institute would have the direction necessary for its success. Improved efficiency of highway transportation, considering all the important private and public costs involved, should be the fundamental goal.
It would be necessary to provide stable and adequate funding. Funding from highway user fees would be appropriate. Carrier contributions for individual projects also would be appropriate. For example, a group of carriers in one industry segment or one region might have a particular interest in having research or a pilot study conducted on a vehicle or operating practice they believed would be of value to them. In such a circumstance, the carriers should be expected to contribute a major portion of the costs of the evaluations. Legislation would be needed to provide the proper legal form for such contributions.
Estimating a budget for the Institute would not be possible until a work plan for the initial activities had been prepared. Preparation of such a work plan would be the initial task of the Institute itself, in consultation with other federal agencies, the states, and interested private-sector parties. The objective of the Institute would be to reduce the public costs (including safety costs and the cost of publicly provided infrastructure) and private costs of commercial motor vehicle transportation. Estimates of past studies suggest that savings could be on the order of several billion dollars annually. If spending of perhaps 1 percent of potential savings were required to conduct necessary oversight and evaluation through the Institute, the cost would not appear unreasonable.
The composition of the Institute’s staff also would be critical. A professional staff with diverse expertise would be essential to conduct the program of research, monitoring, evaluation, and development of regulatory proposals. This staff would have to include economists and other social scientists, statisticians with skills in experimental design and program evaluation, human factors researchers, and mechanical and civil engineers. Staff knowledge of public and private administration also would be necessary.
Three organizations that can provide a model for the Institute are the National Road Transport Commission (NRTC) of Australia, the arrangements established in Canada for development of the 1988 interprovincial agreement on weights and dimensions, and the U.S. Health Effects Institute (HEI). These organizations have had goals
related to those proposed above for the Institute. None of them can be copied directly, since two are in countries whose government institutions differ from those of the United States, and one is from a different sphere of regulation. However, these three organizations are evidence that the proposed arrangement could be successful and indicate some of the keys to success.
National Road Transport Commission
The Australian NRTC, formed in 1991, is making progress on regulatory issues that defied resolution for many years. Its mandate is broad, but among its most prominent projects is development of new nationwide size and weight standards. The key elements of the Australian arrangement are as follows (NRTC 2000):
The NRTC was created by an act of the national parliament and an intergovernmental agreement among all the states and the national government.
The national legislation was a mandate for change in a certain direction, but left the details to be resolved by the commission process. The mandate called for improved road transport productivity, encouragement of innovation, continuous monitoring and updating of regulations as necessary, facilitation of international harmonization, and improvement in the effectiveness and administrative costs of compliance enforcement.
The NRTC’s governing body is the Australian Transport Council, made up of the transport ministers of each state government and the national transport minister. The intergovernmental agreements provide, in spirit, that once the Commission has designed and evaluated a regulation on a topic within its purview and the Council has approved it, the state governments will adopt it. Most of the regulations are regarded as state rather than national responsibilities—a key difference from the U.S. situation, in which there is established precedent for federal preemption of state regulations.
Industry participates actively, but in an advisory capacity. There are no industry seats on the governing body. Funding is entirely from the government, although industry may make in-kind contributions.
The NRTC’s approach is strongly oriented toward relying on research to develop proposals and on ongoing monitoring and evaluation of regulations. The Commission has a role in “coordinating and monitoring” actual adoption of regulations by state governments. Adoption by the states has been at least partly successful, if imperfect.
The NRTC’s mandate covers, in addition to size and weight limits, motor carrier safety standards (e.g., hours of service), road user taxes, vehicle emissions, vehicle safety, and traffic regulations—matters that in the United States fall within the jurisdictions (at the federal level) of EPA, NHTSA, and FMCSA. No such broad mandate would be possible or necessary in the United States. However, there is a gap at the federal level in this country in that no agency has ongoing administrative responsibility for size and weight regulations. FHWA has limited responsibility, but the major features of federal size and weight regulations are not enacted following the same mechanisms as, for example, the rules on truck driver hours of service or motor vehicle emissions—that is, with an executive agency determining the specifics of regulations through rulemaking, following a policy directive from Congress.
Canadian Interprovincial Standards
In 1988 the Ministers of Transportation of the provinces and territories of Canada signed a Memorandum of Understanding on Interprovincial Weights and Dimensions as the culmination of a 5-year effort involving discussions, research, and regulatory development aimed at reducing unnecessary variability in regulation across Canada. As a result of this agreement, the trucking industry in Canada has been provided with minimum, nationally accepted standards for vehicle size and weight that apply to a network of highways across the country.
A major research program was conducted in support of the interprovincial discussions. Research included examination of the influence of size and weight variables on vehicle stability and on pavement performance. The results of the research program were used in developing a set of regulatory principles whereby vehicle performance and highway infrastructure were among the factors that determined the selection of size and weight limits (Pearson 1989). The Roads and Transportation Association of Canada facilitated the interprovincial discussions. The research program was conducted by a nonprofit corporation created for the purpose and funded jointly by the provinces and by industry.
The interprovincial agreement also created a permanent arrangement to monitor developments and improve standards. An appendix to the Memorandum of Understanding created the Task Force on Vehicle Weights and Dimensions Policy, reporting to the Council of Ministers of Transportation, whose members are the transportation ministers of all the provinces and territories and the federal government. The Task
Force’s charge is to develop and recommend a national strategy for the evolution of vehicle weight and dimension regulations in Canada. This arrangement has maintained dialogue between government and industry on technology, regulatory harmonization priorities, and research needs, and has ensured that the national standards are monitored, expanded, and refined to reflect experience and changing circumstances. As a result, the interprovincial standards have been revised three times since 1988. Examples of issues that the Task Force is addressing at present are harmonization of conditions for oversize/overweight special permits, training and accreditation of escort vehicle drivers, and development of common standards for automobile transporters.
As in the case of the Australian NRTC, it was the need to reach agreement among all the provincial governments that provided the stimulus for the Canadian initiative. This exigency does not exist in the United States because of the established strong federal role in size and weight regulation. Nonetheless, the Canadian example shows how the process of seeking agreement among diverse public and private entities can be facilitated by information produced in a manner that is perceived as open, objective, and competent.
Health Effects Institute
HEI is an independent, nonprofit corporation formed in 1980 to provide research on the health effects of pollutants from motor vehicles and from other sources in the environment. It is funded jointly by EPA and industry (HEI n.d.).
HEI is divided into two independent committees—the Health Research Committee and the Health Review Committee—to separate the functions of planning, funding, and administration of research from the function of critical review of research. The Health Research Committee consults with HEI sponsors to determine research priorities and to develop the 5-year HEI Strategic Plan, which is reviewed annually. Once research priorities have been identified, contract proposals are solicited and reviewed with respect to scientific quality and integration with the overall research program. Studies recommended by the Research Committee are finally evaluated by the Board of Directors. The Research Committee monitors research in progress, but its involvement ends when a final report is submitted. The Health Review Committee conducts in-depth evaluation of the final reports and releases the reports, together with the committee’s commentaries, to sponsors and the public.
The most credible and efficient method of addressing many evaluation questions would be a pilot study, that is, a controlled experimental trial of a vehicle specification, element of equipment, or operating practice following a scientifically designed research protocol, and involving collection of data in actual operating conditions or very close approximations thereof. In such a study, the primary impact of interest (e.g., frequency and severity of accidents) would be observed rather than proxies (e.g., vehicle stability or driver performance). A study could be limited to measuring safety effects, some other truck impact (e.g., infrastructure or traffic effects), or a set of impacts. The conduct of pilot studies would probably be the most visible function of the Institute.
A pilot study requires the participation of vehicle operators. Operator participation can allow data to be collected with greater detail, accuracy, speed, and economy than is the case with study designs that do not depend on such cooperation. However, a pilot study of a vehicle proposed for regulatory approval would have an inherent source of bias because industry participants would know they were part of an experiment whose outcome would affect them. Blind trials (the type used, for example, for drug trials conducted to gain Food and Drug Administration approval) usually would not be possible. In most evaluations, there would be no practical way to avoid this potential bias, but the problem would not prevent the pilots from producing useful information if data collection and other procedures were audited by the Institute. Insurance against misleading results would be provided by continuing to monitor the impacts of any vehicle approved for general use after the end of the pilot study.
A study conducted by Consolidated Freightways, a trucking company, that compared accident rates of tractor-semitrailers and twin trailers in the company’s operations illustrates that useful evaluations can be carried out in a study of feasible scale (Glennon 1981, reviewed in TRB 1986, 310–311). The study was conducted for purposes of litigation. If a similar methodology were employed for regulatory applications, a procedure would be established for the oversight agency to verify the integrity of the data. The carrier assembled data for 300,000 trips of tractor-semitrailers and twin-trailer combinations. Each tractor-semitrailer trip was matched to a twin-trailer trip operating on the same day over the identical route. Rates of accident involvement per VMT were computed for the two configurations. The
analysis used historical records of truck trips and accidents from the company’s files rather than data collected for purposes of the study. The matched-pair method allows comparison of accident experience for two vehicle types operated under nearly identical roadway and environmental conditions. The method thus overcomes the principal difficulty involved in comparing the safety of different vehicle types—that differences attributable to vehicle type can be obscured by the effects of differences in the kinds of roads and traffic conditions under which the vehicles are operated.
The pilot study approach is applicable to evaluation of the infrastructure costs and traffic impacts of new vehicles or operating practices. For example, a data collection system could be established for observing the responses of structures and pavements to new vehicles and cumulative infrastructure impacts over a period of up to a few years. The results of such a study would support good estimates of the infrastructure costs to be expected, and would allow the highway agency to plan bridge and pavement management practices that would minimize costs and to set correct user fees that would ensure cost recovery.
Such large-scale studies are not the only research design that would be useful in answering questions about truck impacts. Pilot studies might be relevant primarily to evaluation of new truck configurations preparatory to changes in regulations. Other, smaller-scale studies exemplifying a variety of research designs that could be used to obtain information applicable to regulatory development are identified in Chapter 2.
Sample Size Limitations
In pilot studies involving a small number of vehicles, it would not be possible within a reasonable time span to measure small differences in relative accident risks (Sparks et al. 1988). For example, if the involvement rate in all accidents for one vehicle type were half the rate for the comparison vehicle type, this difference could be detected after a few million truck-VMT of experience, but if the involvement rate difference were 5 percent, hundreds of millions of miles of experience might be necessary to confirm the difference. When pilot studies involved only a small number of vehicles, it would be reasonable to continue operation of the vehicles provided the pilot study results were sufficiently accurate to rule out serious deficiencies, and procedures were in place for continued close observation of the new vehicles’ performance.
A discussion of accident rate measurement problems presented in the DOT 2000 Truck Size and Weight Study implies that direct mea-
surement of accident rate differences among vehicle configurations in the present truck fleet would be nearly impossible because traffic volumes of larger configurations are so low that decades might be required to collect data sufficient for statistically meaningful comparisons (DOT 2000, VIII-2). However, the study that is the basis for the DOT discussion reveals that useful comparisons of the accident involvement rate for all longer combination vehicles with the rate for conventional tractor-semitrailers could be made with 4 years of data from the one state (Utah) for which the necessary accident and traffic information is available (Council and Stewart n.d., 15). This is the period required to measure an accident rate difference of 15 percent; a very large difference would be detected much more quickly, and if more states could be induced to report the necessary data, it might be possible to begin to make comparisons in a matter of months. Moreover, the experimental design of a pilot study, together with required carrier cooperation in reporting accident and travel data, could be expected to allow more efficient measurement of rates than is possible with the passive observation method assumed in the Council and Stewart estimates.
Relation of Pilot Studies to Regulation
A pilot study would constitute an integral step in the regulatory process. An analogy can be drawn between pilot studies and the process by which new drugs are approved by the Food and Drug Administration. When a firm has a new drug it wishes to produce, it approaches the regulatory agency with a plan for demonstrating the product’s safety and effectiveness. The drug evaluations are conducted by private parties under government oversight. Similarly, before a pilot study of a new truck was conducted, the criteria by which the study results were to be judged would be specified. If the evaluation showed that the new vehicles (or new operating practice) failed to satisfy the criteria, it would be necessary to modify the proposal and conduct new trials.
Federal Motor Carrier Safety Pilot Program as a Model
TEA-21 authorized DOT to conduct pilot studies for the purpose of evaluating alternatives to existing federal motor carrier safety regulations or innovative approaches to motor carrier safety (Public Law 105-178, Section 4007). This program provides a model for the pilot study concept, but initial experience also suggests pitfalls to be avoided in the conduct of monitoring and evaluation, thus highlighting the critical importance of the kind of technical oversight the Institute would provide.
TEA-21 allows the Secretary of Transportation to initiate a proposal for a pilot study involving exemption from an existing motor carrier safety regulation and also provides that a carrier can petition for an exemption to be evaluated through a pilot study. Presumably if DOT wished to initiate a pilot study on its own, it would solicit carriers to apply for the associated exemption. The legislation specifies that safety measures in any pilot program must be designed to achieve a level of safety equivalent to or greater than that which would be attained through compliance with existing regulations. DOT is required to have a pilot program plan with the following elements:
A duration for the pilot program of not more than 3 years,
A data collection and safety analysis plan that identifies a method for making comparisons,
A number of participants sufficient to yield statistically valid findings,
Oversight to ensure that participants comply with all terms of the program,
Adequate measures to protect the health and safety of study participants and the public, and
Means of disseminating information to states and the public about the program.
DOT can cancel the pilot or remove a participant if there is a failure to comply with the terms of the program or its continuation would not be consistent with safety. The law explicitly preempts any conflicting state regulations for the duration of a pilot program. (One difference between the structure of the TEA-21 safety regulation pilot program and the size and weight pilot study program described here is that the latter would not involve federal preemption of state regulations; rather, the states would be voluntary participants.) At the end of a pilot program, the law requires the Secretary of Transportation to report the findings to Congress and to recommend any amendments to regulations that would improve safety.
A federal pilot study program that included these general provisions would be suitable for evaluating the consequences of changes in federal size and weight regulations. However, conducting a successful pilot study of changes in size and weight regulations would require scientifically competent data collection and analysis to measure impacts. The first DOT proposal for a pilot program to evaluate changes in motor carrier safety regulations [for a training program to allow drivers under
the regulatory minimum age of 21 years to work as truck drivers after undergoing screening and training (66 FR 10935, February 20, 2001)] did not in its originally published form contain adequate provision for evaluation of safety impacts. The shortcomings of this proposal suggest that Congress must make stronger and more explicit provision for evaluation in enabling legislation for such programs. This need would be the rationale for creation of the Institute.
The DOT proposal for a pilot program to allow commercial drivers under 21 years of age was initiated by petition of a motor carrier association. The association’s proposal includes a plan for a training curriculum and procedures for supervision of drivers, as well as support for a consortium of motor carriers and driver training schools expressing willingness to participate. However, the DOT proposal contains no provision for data collection and analysis to evaluate the safety effect of the pilot program. Under the heading “Monitoring and Evaluation,” the Federal Register notice (p. 10938) states: “Under the [industry association] proposal, each carrier participating in the program would provide monitoring of each younger driver from the day the driver began team driving operations until the driver’s 21st birthday. To satisfy the monitoring requirements, monitoring would, at a minimum, include: face-to-face meetings with the younger driver every 3 months; monthly reviews of the younger driver’s service logs....”
The younger-driver pilot as proposed does not entail any industry reporting of safety-related data to DOT, and would not allow DOT to determine the effect on safety of a change in driver age requirements or of any of the specific training practices and other measures of the pilot program. Thus the evaluation is not in any way analogous to the evaluations in the size and weight pilots described in this chapter. The missing element is an experimental design that would allow DOT to test statistically the effect of the younger-driver program on safety. One such design might be to set up two or three alternative programs involving different kinds and levels of driver screening, training, and apprenticeship and compare their results.
DOT’s proposal for conducting the younger-driver pilot also fails to describe how the program will be judged to have succeeded or failed or how DOT will decide what recommendation to make to Congress at its conclusion. Congress has specified that regulatory changes evaluated in the pilots must not allow any degradation of safety. The pilot study plan should explain how the information collected in the study will allow this congressional criterion to be applied. As noted above, credibility of pilots and private-sector willingness to participate will
depend on establishment of a clear linkage between results and regulatory actions.
TRUCK WEIGHT LIMITS RECOMMENDATIONS
The recommendations for changes in federal regulations of the 1990 TRB study Truck Weight Limits: Issues and Options (TRB 1990a) are presented here primarily as the point of departure for the modified version of these recommendations presented in the next section. In addition, the congressional charge for the present study called for a review of the 1990 study’s recommendations. This section summarizes the recommendations and their rationale and describes the objections that were raised when the study was published. The next section of this chapter describes how the capabilities of the Institute as outlined above could help overcome these objections.
Truck Weight Limits was the product of a study conducted by TRB in response to a provision in the 1987 federal highway act. Federal truck weight regulations and numerous alternatives were evaluated, using the best available engineering and cost information. Federal weight standards have not changed since the study was conducted [with the exception of the weight provisions of the LCV freeze imposed in the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991], nor, regrettably, has scientific understanding of the impacts of changing truck dimensions greatly advanced. Highway conditions have changed with the growth of traffic and continuing investment in the system, but the study’s findings remain relevant nonetheless.
The TRB committee made the following recommendations regarding federal limits (TRB 1990a, 229–232):
New bridge formula—The bridge formula in federal law should be replaced with a new one that is less restrictive for short, heavy single-unit trucks (e.g., dump trucks) and for tractor-semitrailers with more than five axles.
Special permit program—Federal law should be changed to authorize any state to issue permits allowing vehicles to exceed the federal gross weight limit (dropping the requirement that a state must show a grandfather right to issue such permits), subject to the new bridge formula and to requirements regarding routes, fees, and safety restrictions.
Grandfather rights—No new rights should be recognized, but existing rights should not be eliminated. Grandfathered operations that exceed federal axle weight limits or certain specified gross weight
limits should be required to comply with the requirements (other than weight limits) of the new permit program.
In addition, the committee recommended more spending and more effective program design for weight enforcement, and called upon the states to cooperate in standardizing limits and permit practices regionally.
Weights of permitted vehicles would be limited by the new bridge formula. A tridem axle would be limited to about 44,000 lb; a six-axle tractor-semitrailer with a 48-ft semitrailer would be practically limited to 86,000 lb; and an eight-axle double-trailer configuration with 33-ft trailers would be limited to 113,000 lb. The exact limits would depend on the axle spacings of the vehicles. Appendix D contains the complete text of the study’s recommendations.
The distinguishing characteristics of this proposal are as follows:
It allows increases in gross weight beyond the present federal 80,000-lb limit on the Interstates in states that do not have grandfather rights, and for nongrandfathered vehicle types in grandfather states. The significance of the grandfather provisions of federal law as a source of arbitrary differences in state practices is thus diminished.
States have the option of not allowing the increased weights by not participating in the permitting program. (The alternative approach would be a mandatory liberalization of state limits, as the Surface Transportation Assistance Act of 1983 accomplished.)
The federal government would oversee state permitting practices and be more involved in enforcement to ensure that application of the new limits was consistent with safety and economy. Aspects of this oversight would be new federal responsibilities.
The recommendations do not explicitly address LCVs, although certain LCVs would be able to take advantage of the permitting program. The committee’s charge was to evaluate federal weight limits only. Consequently, it made no recommendations regarding vehicle length. In evaluating the proposed new regulations, the committee assumed that each state would retain its length limits unchanged, although the committee anticipated that the federal permit program would be an incentive for some states to increase their length limits so they could operate larger double-trailer configurations on the Interstates.
Objectives and Benefits
The TRB committee stated the objectives with respect to which it evaluated regulatory alternatives as follows:
To select from the various changes in truck weight regulations proposed by industry groups and others the most practical means to realize the productivity benefits of increased truck weights while reducing or eliminating possible adverse effects;
To make changes in weight limits that would reduce truck accidents and encourage safety improvements in truck design and operation;
To provide mechanisms to match user fees with added costs for pavements and bridges;
To promote uniformity in the administration of truck weight regulations;
To balance the federal interest in protecting the national investment in the Interstate system and facilitating interstate commerce with the interests of the states in serving the needs of their citizens and industries;
To develop proposals that are realistic and feasible and would have a reasonable chance of being implemented. (TRB 1990a, 228)
The TRB study committee estimated that if all states chose to participate in the permit program, about a third of the mileage of all large trucks (that is, heavy single-unit trucks as well as combination vehicles) would adopt new configurations. The vehicle experiencing the greatest growth in popularity would be the six-axle tractor-semitrailer. Users of heavy single-unit trucks, such as dump trucks and garbage trucks, would benefit, primarily by replacing three-axle with four-axle trucks. A small amount of freight was predicted to shift from tractor-semitrailers to short, heavy double-trailer combinations. Traffic equivalent to 1 percent of annual large-truck-VMT would be diverted from railroads to the highways, but the total annual mileage of large trucks would decline by more than 3 percent compared with traffic volume if the federal limits were not changed.
With these projected levels of use, annual freight transportation costs were projected to decline by $5.2 billion (in 1995 prices and freight volumes) or 2.6 percent of the prior total cost of truck freight transportation. Highway agency pavement costs would be nearly unchanged, but annual bridge construction and maintenance costs were projected to increase by $900 million, primarily for replacement of bridges deficient for carrying the heavier vehicles. Accident losses were projected to decline because the reduction in truck-VMT would more than offset any greater risk per mile of travel of the new trucks com-
pared with the vehicles replaced. The TRB committee concluded that these projected outcomes matched the defined objectives better than any of the range of alternatives within the scope of the study and so recommended adoption of the new regulations.
Objections and Obstacles
The Truck Weight Limits proposal continues to be worthy of consideration. Freight productivity benefits would exceed highway agency costs of accommodating the larger trucks, according to the evaluation in the study. Moreover, as argued in Chapter 2, the analysis method used in the study tends to overestimate bridge costs because it does not take into account bridge management techniques for reducing those costs. Finally, it may be argued in the proposal’s favor that it would provide a mechanism for adjustment of federal regulations with some degree of planning and control and would therefore be preferable to the stop-gap measures and haphazard erosion of existing standards that appears to have been the pattern of recent years. Before judging whether implementing the proposal today would be advisable, it is necessary to consider changes in the environment since the study was conducted and the criticisms aimed at the study when it was released.
Changes Since 1990 in the Highway Transport Environment
Since the TRB committee issued its recommendations in 1990, some factors in the environment have changed that would affect the consequences of adopting those recommendations. Truck and automobile traffic has grown, and more time is lost to congestion today than in 1990. However, with federal leadership beginning with the 1983 STAA and continuing with the ISTEA (1991) and TEA-21 (1998) highway programs, spending on roads has increased significantly, and progress has been made toward improving the physical condition of bridges and pavements (DOT 1999).
Traffic of containerized freight, much of it in international trade, grew rapidly in the 1990s. U.S. weight limits are lower than the limits of most of the nation’s trading partners, and heavier six-axle semitrailers operating under the Truck Weight Limits permit program would be well suited to carrying international containers. Indeed, the benefits of increased truck productivity may appear more attractive today because of emergent concerns over capacity constraints throughout the freight transportation system.
Average fatal accident involvement rates for trucks have declined since 1990, possibly rendering any relative differences in accident rates among vehicle types somewhat less significant. Some data indicate that
average loaded truck weights may be decreasing (DOT 2000, Vol. II, III.8), a trend that could affect the productivity benefit of adopting the TRB recommendations. Resources devoted to truck regulatory enforcement have increased, although measurement of the effectiveness of regulation remains poor, as discussed in Chapter 4.
The significant federal regulatory change since 1990 has been enactment of the LCV freeze in 1991, which prevents states from claiming any expansion of grandfather rights to operate heavier multitrailer configurations on the Interstates and blocks changes in state regulations that would expand use of multitrailer configurations on the National Network for Large Trucks (which includes 160,000 mi of roads in addition to the Interstates) (DOT 2000, Vol. III, III.17). The LCV freeze would restrict states’ options for taking advantage of the proposed permitting program.
Criticisms of the Truck Weight Limits Proposal
The most serious objections raised to the original Truck Weight Limits proposal upon its release concerned implementation. The proposal incorporated requirements regarding routes where permit vehicles would operate, user fees for permit vehicles, enforcement, and safety practices. These requirements were stated in general language and left to the discretion of the states or as regulatory details to be worked out by FHWA in promulgating regulations to govern the permit program. Some state officials and others argued that technical expertise, institutional arrangements, financial and human resources, and political support that would be essential for putting these safeguards in place were all lacking. State officials were concerned that the end result of attempting to implement the study’s recommendations would be that the states would be forced to accommodate larger trucks and to incur added infrastructure costs without the needed additional revenue (which according to the proposal should come from permit fees and other user fees) and without the strengthened enforcement and safety checks the study said would also be necessary.
These concerns find support in past experience. Truck permit fees often are insufficient for covering the costs of administration and enforcement of the permit programs, let alone for recouping added infrastructure costs generated by permit vehicles (see Chapter 4). At the federal level, truck excise taxes were increased on a graduated scale with respect to weight in STAA, the 1983 law that required all states to allow 80,000-lb trucks, but the graduated fee schedule was repealed 2 years later.
On enforcement, the Truck Weight Limits proposal contained a partially dissenting statement by a committee member who was a state enforcement official, presenting two objections. First, the study’s evaluations did not include sensitivity analysis of how the projected benefits and costs of the options would change if differing assumptions about the effectiveness of enforcement were made. The statement’s author believed that under the permit program, the average infrastructure damage cost of violations would rise and that the added complexity of the permit program would make it more difficult to enforce than existing regulations. Higher cost per violation and greater frequency of violations might annul the projected benefits, the statement argued. Second, the author of the statement noted that although the report listed possible federal actions to strengthen state enforcement, the recommendations did not call for any specific new federal initiative regarding enforcement.
As discussed in Chapter 4, federal oversight of state enforcement programs has historically been weak. Implementation of the Truck Weight Limits proposal would heighten the importance of the federal oversight role.
Finally, regarding the proposal’s recommendation that permits issued under its recommended procedures include provisions requiring special equipment or operating practices to ensure safety, the results of the review of safety evaluations of size and weight limits presented in Chapter 2 indicate that the effectiveness of most such measures is largely unknown. Therefore, this part of the proposal’s recommendations, by itself, would not provide strong assurance of safe operation of permit vehicles, even if it were vigorously implemented.
MODIFIED VERSION OF TRUCK WEIGHT LIMITS RECOMMENDATIONS
In this section, a proposal for reform of federal size and weight regulations is outlined that retains the core concept and most of the objectives of the Truck Weight Limits recommendations, but includes provisions intended to overcome some of the problems identified in criticisms of that study. The specific size and weight provisions outlined below are presented as an interim arrangement rather than as a permanent resolution. Implementing the proposal would create a mechanism whereby the performance of the regulations and the states’ administration of them could be monitored and evaluated, and adjustments made when warranted by the evaluations and by changes in external conditions. The Institute proposed earlier in this chapter would be a suitable
organizational arrangement to provide technical support for these functions. Recommendation 3 in Chapter 5 specifies in greater detail the necessary oversight functions and the proposed responsibilities of the Institute.
Two modifications to the Truck Weight Limits proposal are described below: changes in the earlier study’s size and weight limit recommendations, and stronger and more specific provisions to ensure that implementation is effective in furthering the objectives of the regulations. The modified proposal retains the central feature of the original: a federally supervised, state-implemented permitting program, adopted at state option, to allow operation of certain trucks larger than those now allowed under federal law on the Interstates and other roads where federal restrictions currently apply.
Size and Weight Provisions
In this modified regulatory proposal, specific size and weight provisions that differ from the original Truck Weight Limits recommendations are as follows:
An immediate change in the federal bridge formula is not proposed. How the new bridge formula would influence equipment selection in actual practice is difficult to predict and an important source of uncertainty in the original study’s impact estimates. Also, since 1990 other proposals for modifications to the bridge formula have been made, so reassessment probably will continue in the future.
Instead of defining the trucks that would be eligible for the new permit program solely by a bridge formula, specific eligible configurations are identified: a six-axle tractor-semitrailer with maximum weight of 90,000 lb (regardless of the bridge formula restriction) and double-trailer configurations with each trailer up to 33 ft long, seven to nine axles, and weight limit governed by the present bridge formula, implying a maximum weight of about 111,000 lb. These would be the maximum weights and dimensions allowed, but a state could apply to participate in the program and to impose more restrictive limits on its permitted trucks. For example, a state could propose to impose a bridge formula on the six-axle tractor-semitrailer. The specificity of this approach might be attractive to state officials, in contrast to the uncertain outcome of application of the new bridge formula proposed in Truck Weight Limits. On the other hand, specificity curtails operator flexibility and innovation. Federal permission to use heavy doubles would constitute a limited relaxation of the present federal LCV freeze.
After a specified transition period, all trucks operating under grandfather exemptions or state-specific exemptions from federal regulations would be made subject to the requirements for monitoring and evaluation that would apply to trucks in the proposed new state permitting programs. Information from monitoring would allow Congress to decide whether the grandfather provisions should be altered. Alternatively, grandfather rights could simply be sunset after a period of time. When the permit program and the needed federal oversight capabilities were in effect, carriers and states would have the opportunity through these mechanisms to use almost any economically justifiable vehicle, and with more effective controls to prevent abuse than now exist in grandfather rights operations.
The six-axle 90,000-lb tractor-semitrailer, one of the vehicles that would be eligible for the permit program, is evaluated as carefully as existing information allows in the DOT 2000 size and weight study and in Truck Weight Limits. This vehicle is considered in the DOT and TRB studies because (1) it offers a modest productivity gain over the current standard five-axle tractor semitrailer (the TRB study estimates about a 5 percent savings per ton-mile for high-density cargo); (2) it would reduce pavement wear costs per ton-mile of truck freight because it provides carriers an incentive to adopt trucks with lower average axle weights; and (3) the total weight and weight distribution would be consistent with criteria for acceptable levels of bridge stress that are the basis of current federal regulations. The desire to limit the extent of potential bridge overstress is the principle constraint on the weight of the vehicle in the two earlier analyses.
The DOT study further notes that allowing use of the heavier six-axle tractor-semitrailer would reduce the discrepancies between U.S. limits and those of Canada and Mexico and between U.S. limits and the weights of standard containers in international commerce. The six-axle tractor-semitrailer is similar to trucks used widely today in many other countries.
Double-trailer combinations with 28-ft trailers and gross weight of up to 80,000 lb operate legally in every state by federal law, and 22 states allow operation of longer and heavier multitrailer combinations. Short, heavy double-trailer combinations are evaluated in the DOT 2000 study, in Truck Weight Limits, and in the Turner Proposal study (TRB 1990b). The proposed 33-ft trailer length limit on the double-trailer permit vehicles would allow this configuration to make turns at intersections without encroaching farther into the
opposing lane than do common existing tractor-semitrailers. The evaluations in past studies indicate also that the 33-ft trailer length would offer some advantages with respect to stability as compared with 28-ft trailers.
There is no basis for claiming that these weight limits are optimum. They would be expected to be subject to revision over time. The federal review of state permit programs would be permanent and ongoing, and as its effectiveness was strengthened through experience, the review process would yield results that would provide the needed guidance on revision of the limits.
As explained in the preceding section, serious objections to the Truck Weight Limits proposal concerned implementation problems: How could the study’s recommendations regarding adequate fees; adequate enforcement; and assurance of safe operation through imposition of vehicle, operational, and routing restrictions be made to work in practice, considering the history of federal and state failings in these areas? Outlined below are proposals aimed at increasing the likelihood of successful implementation of the permitting program by putting teeth into the federal oversight of enforcement, fees, and safety requirements. The key to improved results in each of these areas is effective evaluation and monitoring. If regulatory agencies cannot observe how the programs they administer are performing with respect to their objectives, the chance of success is small.
The federal legislation creating the program would contain a quantitative test for revenue adequacy of the permit fees imposed by states that wished to participate in the new permit program. Fees should be sufficient to cover all costs of administering and enforcing the permits, as well as any increase in infrastructure cost caused by the permits. The ability of the permit program to cover its costs is a necessary test that it is economically justified. States that decide to participate in the program should be required to provide DOT with the data necessary to verify revenue adequacy.
An effective joint federal–state program for enforcement under the permit program would include the three elements listed below. The federal legislation creating the new federal truck size and weight reg-
ulatory program would have to contain specific requirements regarding each of these elements:
Performance benchmarking—A state participating in the program would be required to have in place a data collection program that allowed it to know the actual distribution of axle weights and gross weights on significant truck routes and the frequency of extreme overloads, and that allowed it to observe the effect of enforcement efforts on the frequency and severity of violations.
Application of new enforcement tools—The list in Truck Weight Limits of possible federal measures to strengthen enforcement remains valid (pp. 142–143). That study recommends a federal evaluation of these measures but does not explicitly recommend any federal action regarding enforcement. The measures identified are as follows:
Imposition of federal penalties for violation of federal limits. Penalties might include fines and other penalties, such as forced offloading of trucks and revocation of the driver’s commercial driver’s license for serious violations within the driver’s control, such as ignoring a bridge posting. Federal penalties could also be imposed on carriers and on shippers, depending on where responsibility lay for placing the overload on the highway.
Federal programs to educate judges, prosecutors, and state law enforcement officials about the importance of the problem.
A strong federal action would be to make enactment of a “relevant evidence” statute a precondition for state participation in the permit program. A few states authorize enforcement officials to conduct terminal and office inspections of shippers and receivers to find evidence of haulage of illegal loads and to utilize the records in prosecuting weight violations (TRB 1990a, 275).
Adequate and stable funding—One of the possible federal actions listed in Truck Weight Limits is direct federal funding of state enforcement, possibly by amending the federal Motor Carrier Safety Assistance Program. If federally funded enforcement were financed through federal truck user fees, this approach might be the most direct way to overcome state objections on enforcement grounds and to stimulate improvements.
A program to substantially advance the application of information technology as an enforcement tool—Information technology applications that are available today could, with the proper institutional support, dramatically improve the effectiveness of enforcement.
Truck Weight Limits recommends that FHWA, the states, and industry jointly develop standards that would improve the safety of the vehicles operating under the new permit program in the areas of power requirements; driver qualifications; accident reporting; brakes; couplings; and axle, tire, and rim specifications. States would be required to impose these standards on permit vehicles. The problem with this recommendation is that little is known about the relationship of the vehicle characteristics cited, or of driver qualifications, to on-the-road accident risk. Therefore such standards, derived from present knowledge, could not be relied upon to ensure safe operation. A substantial commitment to research would be needed to establish the efficacy of such a requirement. As a temporary measure, equipment requirements developed in established state permit programs could be imposed. For example, some states require that a permitted truck’s components carry manufacturers’ ratings consistent with the loads the truck is allowed to carry. As an accompaniment to enactment of the permit program, federal legislation could provide resources and an institutional structure for the research program on the relationship of vehicle design and performance characteristics to accident risk. An arrangement for this purpose was described in the first section of this chapter.
As described in Chapter 2, knowledge about the relation of truck size and weight to safety is weak. This uncertainty leaves room for a substantial probability that safety effects of changes in regulations would be large, even if best available estimates indicated that they would not be. Nonetheless, it would be reasonable to hope that implementing the regulatory changes described in this section, in conjunction with the permanent data collection and research arrangements outlined in the first section of this chapter, would contribute to safety. Such a program would be a first step toward imposing effective oversight and performance monitoring on a regulatory system that today is haphazard and poorly monitored, as Chapter 4 will describe. In addition, the research and evaluation activities could greatly strengthen the scientific basis of truck and highway safety programs.
Redefinition of Federal and State Responsibilities
The permit program, implemented with effective federal oversight of safety, fees, and enforcement, would constitute a redefinition of the federal role in size and weight regulation. The federal government would have diminished involvement in defining numerical dimensional limits on the Interstates and other federal-aid highways, since the states would
have more discretion with respect to limits on these roads. However, the federal government would take on greater responsibility for ensuring that state rules governing the use of vehicles on federal-aid highways were contributing to meeting national objectives.
Historically, the central provision of federal size and weight regulations has been the numerical limits on weights and dimensions, either maximum limits (for weight and width) or rules forbidding the states to impose limits below certain values (for trailer length and number of trailers). Policy debates have focused on setting these numerical values. However, the federal government has paid little attention to how its numerical limits affect the performance of the highway transportation system. It does not systematically monitor how federal and state regulations, exemptions, permits, and regulatory violations combine to determine the characteristics of trucks in operation; federal oversight of state enforcement of the federal limits has been imperfect; and evaluations of the regulations’ impacts in the federal truck size and weight studies have been infrequent and have been weakened by methodological flaws and data gaps.
The committee envisions that the structure of the recommended permit program, together with the capabilities for monitoring, oversight, and research provided by the Institute, would eventually lead to a regulatory regime in which federal numerical limits would have much less importance because states would have greater flexibility to set their own limits. However, federal monitoring of the performance of the regulations would play a much stronger role than it does now in determining how trucks are regulated. In effect, federal oversight would tend toward performance standards: states could propose solutions to problems, and the federal government would have to assess whether the proposals met qualitative objectives. The redefined federal role, by requiring states to justify their proposals on performance grounds, would allow the federal government to continue to provide a buffer between state highway programs and local, short-term economic pressures to depart from best management practices, as federal standards do now.
The opportunities created by the permit program would be expected to stimulate new multistate agreements on size and weight. Federal administration of the program could promote or require consultation among neighboring states. Expansion of multistate agreements would be consistent with evolution away from reliance on federal numerical standards. Some regional multistate agreements on matters related to size and weight matters already exist. Multistate
agreements could improve regulation if they promoted best practices and reduced needless variability in regulations. They could be useful in situations in which several adjacent states have similar road conditions that differ from those of surrounding states (e.g., a group of states having relatively new Interstates with relatively light traffic), or in which a regional industry that extends across state lines requires a special provision in the regulations.
The federally supervised permit program would be expected to promote multistate agreements for two reasons. First, states would have more flexibility to change regulations than they now have. Second, the federal oversight function would provide a formal mechanism for states with similar needs to develop common regulatory responses. As a hypothetical example, if each of a group of neighboring states saw a need to provide in its size and weight regulations for special requirements of a regional industry (and the changes were not possible under present federal rules), each state would be required to apply to the federal government for review and approval of a permitting program. The federal review would examine infrastructure compatibility, provisions for safety, and user fees. It often would be preferable from the point of view of the affected industry, the state governments, and the federal program administrators if the states devised a common solution to the regulatory problem rather than multiple, arbitrarily differing solutions.
The program would also foster innovation. States, shippers, carriers, and equipment manufacturers would have opportunities for presenting new ideas and demonstrating their effectiveness.
At least one North American jurisdiction, the Province of Saskatchewan, today operates a permit program with several of the essential features of this proposal. The Saskatchewan program illustrates the concept and gives some indication of practical administrative requirements. The province authorizes use of vehicles exceeding statutory dimensional limits under the terms of contractual agreements negotiated with individual operators. The program has antecedents dating back to 1977. Under present procedures, an operator seeking permission to use larger trucks first pays for a feasibility study conducted by the provincial highway department. If the study results are favorable, an agreement is drawn up specifying allowable vehicle dimensions, equipment specifications and maintenance procedures, allowable routes, and driver qualifications. The agreement also specifies fees to be paid, which are calculated to cover all incremental road and bridge costs incurred by the province plus half the estimated remaining cost savings to the operator from use of the larger trucks. The fee
is deposited in a special fund that may be drawn upon for highway improvements mutually agreed upon by the province and the private-sector participants, as well as for research, truck safety activities, and program administration. Some agreements call for the private-sector operator to deliver the road improvements necessary for operation of its vehicles.
The program has been used primarily to allow operation on secondary roads of trucks that meet the state’s normal primary road dimensional standards, but some larger configurations also are operating. The number of participants is small at present. The province would like to see participation expand, but recognizes that a larger program would require more streamlined administrative procedures (Lang et al. 2001; Saskatchewan n.d.).
PROGRAM FOR LARGE REDUCTIONS IN SHIPPER COSTS
The TRB and DOT size and weight policy studies described in Chapter 2 considered regulatory alternatives involving liberalization of limits beyond the Truck Weight Limits recommendations. The methods and assumptions used by those studies imply that liberalization would yield benefits up to a point where trucks substantially larger than those now in use were allowed in those regions where road and traffic conditions were suitable. The proposal outlined in this section indicates the kinds of limits that would be closer to efficient practice, that is, to limits that would allow the public road system to yield the greatest public benefits according to the results of those earlier evaluations. Efficient use of the nation’s highways means extracting the greatest economic benefit from the existing highway system and from future highway investments, taking into account the costs imposed by vehicles on other highway users and on the public. Efficient use of the public road system requires the right government policies regarding highway design, operating practices, and user fees. Size and weight regulations can contribute to efficiency if they are combined with appropriate policies in all these areas.
The proposal is not presented as a package to be considered for early implementation. Because of the uncertainties and flaws in the projections of the past studies, the risk of unanticipated harmful consequences arising from radical change in the limits would be great. However, the past studies’ results raise the possibility that worthwhile public benefits could be gained from regulations such as those outlined below. The Institute proposed earlier in this chapter would be a suitable organization to conduct the research and evaluation that would be
needed before decisions were made on implementation. The recommendations in Chapter 5 regarding pilot studies and research indicate some of the necessary activities.
The size and weight provisions in the proposal are as follows:
Replacement of existing federal weight regulations with a new federal bridge formula without a weight maximum, but retaining the present federal single- and tandem-axle weight limits. Candidates for the formula would include the “Uncapped TTI HS-20” formula or the “Combined TTI-HS-20/Formula B” defined in Truck Weight Limits (pp. 189–204).
Introduction of a new federal tridem-axle weight limit of 51,000 lb.
Federal authorization of operation of six-axle tractor-semitrailers of up to 97,000 lb, eight-axle B-train double-trailer configurations of up to a specified weight, and eight-axle twin 33-ft trailer combinations of up to a specified weight on a specified system of roads (this provision could be either a federal requirement, like the 1983 federal law requiring the states to accept twin trailers and 80,000-lb semis, or a state option).
A provision allowing limited expansion, as a state option, of use of turnpike doubles and of triple-trailers in rural areas.
This package would be consistent with proposals from some segments of industry, including the Peterson-Cook bill first introduced in Congress in 1999, which would allow 97,000-lb trucks at the option of each state and which are supported by a group of shippers and carriers. The package would be similar in effect to the present Canadian interprovincial limits, which were adopted by all the provinces in 1988 after completion of a government–industry research program (RTAC 1988). The Canadian limits make no provision for turnpike doubles or triples.
Although NAFTA requires the United States, Canada, and Mexico to seek harmonization of standards related to vehicle weights and dimensions, progress has been slow to date, and great disparities exist in limits among the three nations. By allowing U.S. operation of trucks with dimensions closer to those employed in Canada and Mexico, the proposal would largely accomplish harmonization.
The proposal outlined here embodies a continued strong federal role in direct regulation of truck dimensions (in contrast to the proposal in the preceding section), as well as in finance of needed infrastructure
and in monitoring of program performance. Similar outcomes probably would be attainable through a more flexible regulatory regime or with greater devolution of responsibility to the states. The strong federal role might be justified because leadership would be important in making such a large change in regulatory practice and also perhaps because funding needs might be very unevenly distributed among the states.
Truck Weight Limits evaluates application of the Canadian interprovincial limits to the United States. The “North American trade” regulatory scenario (in the version that assumes establishment of a 51,000-lb federal tridem axle weight limit) in the 2000 DOT study also envisions use of similar configurations (DOT 2000, Vol. III, III.10–III.17). The key vehicles in both these evaluations are the 97,000 tractor-semitrailer and the 131,000 short, heavy double-trailer combination; neither evaluation addresses expanded use of turnpike doubles or triples. The estimates in these two studies suggest the potential for impressive public benefits.
Truck Weight Limits estimates that nationwide application of the Canadian interprovincial limits would yield annual shipper cost savings (at 1995 prices and traffic volumes) of nearly $12 billion, equal to 6 percent of the prior costs of all truck freight transportation. The negative aspect of the evaluation in Truck Weight Limits is the estimate of infrastructure costs. Annual bridge costs are predicted to increase by $2.4 billion and pavement costs by $500 million. If bridges were replaced to accommodate the larger trucks only on principal highways, bridge costs would be $1 billion annually.
The DOT 2000 study estimates similar freight cost savings for its “North American trade” scenario (with a 51,000-lb tridem-axle weight limit). Projected annual private freight cost savings are $14.5 billion (at present-day traffic volumes and prices). Savings to prior truck users are estimated to be 6 percent of prior expenditures on truck freight (DOT 2000, Vol. 3, p. XII.4). As in the TRB study, the major drawback, according to the estimates, is the cost of replacing bridges judged inadequate to carry the heavier trucks. Estimated bridge replacement costs total $65 billion, or $4.5 billion annually if amortized at 7 percent as assumed in the TRB study. Even more problematic is the estimate of $329 billion (or $23 billion/year) in the costs of delay to highway users due to bridge construction projects (DOT 2000, VI-12).
Obstacles and Uncertainties
Among the most apparent problems in implementing such a proposal would be managing bridge costs, financing highway improvements, and maintaining safety.
Although the Canadian interprovincial limits showed the greatest net benefits among all options evaluated, the Truck Weight Limits committee presumably did not recommend adoption of those limits in part because of the magnitude of the estimated bridge costs, especially the up-front expenditures that would be needed in the first few years after the limits were changed, according to the study’s cost estimation methodology, to accommodate the new trucks on a useful network of major roads. In the DOT evaluation, the addition of delay costs due to bridge construction (a cost ignored in the TRB study) boosts the costs of its “North American trade” scenario (but not of all the LCV scenarios evaluated) above the benefits.
Chapter 2 explains why the method used to derive bridge cost estimates in the past studies is inaccurate. It is likely that if the trucks evaluated in these studies came into use, it would be feasible to maintain or reduce the risk of bridge failures at lower cost than these studies’ estimates through more intensive inspection and maintenance of bridges, routing restrictions, and more effective enforcement. Some states with older bridge stocks, lower historical design standards, or less adequate maintenance programs would face the need for substantial bridge replacement expenditures. States would also encounter costs for early replacement of bridges because of accelerated fatigue deterioration. Providing the necessary institutional and financial support for improved bridge management and for justified bridge replacements would be a challenge for the state highway agencies.
Even though there are grounds for regarding past studies’ bridge cost estimates as misleading, states would face initial and continuing costs for accommodating trucks of the dimensions provided for under this proposal. Therefore, a financing plan would be essential for implementation. The keys would be raising the necessary funds from users of the new equipment, and implementing a program for prioritizing and staging bridge replacements that took into account the importance of routes to freight traffic. The most reliable test of the economic justification of the new regulations would be carriers’ and shippers’
willingness to finance genuinely necessary infrastructure upgrades through user fees or other financial arrangements with states.
Historical experience with similar vehicles, including experience in other countries, together with the available research results, although imperfect and fragmentary, provides sufficient justification for the conduct of trials to demonstrate the safety of the vehicles this proposal would bring into common use. The trials would have to be large enough to generate data sufficient to calculate differences among vehicle configurations in accident involvement rates and to assess the effectiveness of mitigation measures. Careful experimental design of the trials would be essential. Conduct of large-scale trials would be the only means of putting to rest doubts about safety impacts.
INCREASING THE EFFECTIVENESS OF REGULATION: PERFORMANCE STANDARDS AND PRICING
Opportunities exist to establish a direction for reform of size and weight regulations and related highway management practices that would lead to a more efficient and safer highway system in future decades. Incremental regulatory changes, as they occurred, could be made in such a way that progress would be maintained toward an eventual transformation of size and weight regulation into a highway management mechanism fundamentally different from present practice. The principles underlying the new scheme would be regulation by performance standards and pricing to provide truck operators with financial incentives to choose efficient equipment and operating practices.
Performance standards would directly limit the behavior of vehicles instead of limiting dimensions or requiring specific equipment or appurtenances. For example, one source of the concern that increasing the gross weight limit might degrade safety is that if gross weight is increased for a vehicle of a specified length, the vehicle’s center of gravity is likely to be elevated. Therefore, it will have a greater propensity to roll over in use, and hence will be at greater risk of involvement in accidents. The performance standards approach would involve first verifying that this causal chain is valid and then regulating some direct measure of propensity to roll over, instead of attempting to regulate the rollover hazard indirectly (and probably ineffectively) by means of the gross weight limit. All vehicles that had high rollover risk would be
affected by the application of such a standard (rather than just those vehicles operating at the gross weight limit), and operators would have an incentive to find ways of reducing the rollover propensity of their trucks without sacrificing productivity.
The term performance-based standards denotes an approach to vehicle regulation that is intended to yield some of the benefits while avoiding the implementation difficulties of pure performance standards. A performance-based standard is a dimensional limit on vehicles that is derived from and justified by an explicitly defined performance standard. For example, the performance standard might be ability to perform a specified turning movement without encroaching more than a specified distance into the opposing lane. Dimensional limits (e.g., on spacing between articulation points) derived from this standard would be promulgated as performance-based standards.
The performance-based standards approach has the advantages that each dimensional limit has a clear rationale. If more is learned through research about the relation of safety (or other vehicle operating costs) to the performance in question, or if innovation leads to new techniques for satisfying the performance standard, the dimensional standard can readily be revised. In contrast, some dimensional limits in effect today are fossils, justified originally on the basis of highway conditions that have not been relevant for decades. The performance-based standards approach is being explored as a basis for harmonization of international limits under the NAFTA accords (LTSS 1999) and is the basis for national standards under development in Australia (NRTC 2000, 11–14).
The success of performance standards depends on empirically establishing the links between performance measures and accident risks and bridge and pavement impacts, and on designing a practical certification process. The performance–risk linkages are not known and must be established by research.
The benefits of any of the standards described above would be increased if they were adopted along with a system of user fees more closely aligned with the public costs generated by each truck trip. Although Truck Weight Limits recommends that fees related to costs be adopted to accompany the proposed new size and weight limits, that study’s evaluations of regulatory alternatives assumes that no changes in the structure of user fees would occur. As a consequence, even in regulatory options that show large net benefits in the evaluations, changing
the regulations would stimulate some truck operations of questionable economic value. For example, several of the options outlined in the study would encourage use of five-axle twin trailers with weights of more than 90,000 lb, a vehicle that generates relatively very high pavement wear costs (TRB 1990a, 195–196). Charging these vehicles for the costs they incurred would eliminate this problem by stimulating most operators to choose more road-friendly configurations and by providing the revenue needed to repair wear caused by users who did use the high-cost vehicles. Proper user fees would in this way separate the beneficial uses from the uneconomical ones, magnifying the net economic benefits of the new limits. Metering road use would not be fundamentally more difficult technically than metering the use of other public utilities—telephone, electricity, or water.
Matching fees to costs would greatly facilitate the implementation of any new standards that promised net benefits but required investment in upgrading infrastructure. The new user fees would provide the revenue the state highway agencies needed to carry out the upgrades. The state would take on a risk in making the initial, most essential upgrades, but over time the state could defer upgrades until revenues for the new truck fees began to materialize, to reduce the risk of overinvestment.
In the proposal outlined above for a federally supervised state permitting program, states would impose fees on permit operators related to the costs of operating the permit trucks. The estimates of past studies summarized in Chapter 2 indicate that costs arising from the new trucks’ impacts on bridges would be the largest category of highway agency costs of the program. Even if the highway agency understands its bridge costs well, charging trucks for bridge impacts of the federally supervised permit program outlined above would present difficulties.
As described in Chapter 2, the cost of a passage of a permit truck would vary greatly from bridge to bridge, and therefore fees truly reflective of costs would have to depend on the routes each permit vehicle used. Some states already have procedures for evaluating bridge capacities on individual routes as part of their procedures for reviewing permit operations. However, levying route-specific fees and enforcing route restrictions for large numbers of permit vehicles would be a formidable administrative undertaking; therefore simpler fee schemes would be acceptable in some circumstances, particularly where bridge impacts were expected to be small for a particular vehicle class in a particular state. It would be technically feasible today to automate
route monitoring with the automatic vehicle identification technology described in Chapter 4.
As also described in Chapter 2, it is likely that there are many bridges that could safely bear the loads of larger trucks but which would require greater expenditure for maintenance and inspection and would have reduced useful lifespans. Methods of estimating these costs exist and have been applied, although present models do not lead to very precise cost estimates. These added costs might be proportional to the volume of permit traffic up to some traffic level but increase at an accelerating rate at higher volumes. Therefore the appropriate fee to charge a permit truck could depend on the volume of permit traffic on the routes the truck used. If accelerating costs were not detected, the state would face the risk of financial loss and possibly of degraded safety. Also in such a circumstance, bridge fees equal to the average cost per truck of use of the bridge would be too low to cover the marginal cost of additional permit traffic and would therefore encourage uneconomic permit operations.
A state adopting the permit system might determine that some of its bridges would be inadequate to carry the larger trucks safely. The state would have to decide whether to bar the use of these bridges by the permit trucks or to replace or strengthen them, and also how to finance any replacements or strengthening. Borrowing on expected revenues from future permit users of the bridge would entail financial risk for the state but might be the best compromise solution to this problem. There would be some cases where most of the benefits of replacing a bridge would be gained by a small number of shippers or carriers (for example, a bridge on a lightly traveled road that is the access route to a mine). It would be reasonable for the state to seek direct financial participation of these beneficiaries before replacing the bridge.
Finally, estimates for the DOT 2000 truck size and weight study presented in Chapter 2 indicate that the cost to highway users of traffic delays caused by bridge construction is significant, sometimes exceeding the highway agency’s construction cost for bridge replacements or improvements. One purpose of charging fees to permit trucks would be to ensure that the costs to the public of operating the trucks did not exceed their benefits, and the fees should on this principle reflect the delay costs as well. At least, the states should measure delay costs at construction sites, employ all cost-effective measures for reducing them (for example, by accelerating construction schedules and through traffic management), and, if construction is undertaken to accommodate
permit trucks, cover the cost of these delay-reducing measures with fees imposed on the permit trucks.
The 1989 economic study Road Work, described in Chapter 2, presents evidence that even if no change were made in truck size and weight limits or in highway agency design practices, and if a very simplified form of road pricing for trucks were introduced, pricing would yield substantial economic benefits by providing operators with incentives to select equipment and routes that reduced pavement wear (Small et al. 1989). Benefits could be much greater than estimated in that study if operators also were allowed to carry heavier loads when they were willing to pay any added infrastructure costs or to adopt equipment that mitigated those costs.
The failure under existing institutional arrangements to adequately evaluate the performance of size and weight regulations and the lack of progress on improving understanding of many aspects of the costs and benefits of truck transportation point to the need for creating a new organization authorized to conduct research in support of development of federal size and weight standards, to recommend regulatory changes, and to monitor and evaluate the results of regulation. Strong federal oversight of state permitting, a component of two of the regulatory proposals outlined in this chapter, also would require new organizational arrangements since it would be a function not matching the responsibilities and competence of any existing federal agency.
Valid concerns have been raised that the Truck Weight Limits study underestimates the difficulty of putting into effect the enforcement, safety, and fee provisions recommended to accompany new federal weight limits. A modified version of the Truck Weight Limits permit program might constitute a package of reforms with greater credibility. This modified version would include simpler weight limit provisions initially and stronger legislatively defined federal oversight responsibilities, including effective monitoring of performance. It also incorporates ongoing research and evaluation with competent independent oversight that would reduce uncertainties about costs and benefits of regulatory alternatives, leading to continuing improvement in the regulations and reduction of the public and private costs of commercial motor vehicle transportation.
The modified version of the Truck Weight Limits recommendations outlined in this chapter involves modest changes in the federal limits. However, evaluations in past studies and experience in some regions
of the United States and abroad suggest the possibility that greater increases in truck productivity would ultimately be possible that would yield greater public benefits. The results of the past studies regarding the more radical liberalization proposals are too uncertain to provide a basis for action, but the proposals deserve adequate evaluation.
Incorporating performance standards and rational pricing would magnify the effectiveness of any of these regulatory reforms. The federal oversight of state permit programs could evolve toward regulation based on performance standards, but research is essential to link measurable vehicle performance indices to actual on-the-road safety and economy. Although past studies often have recommended that truck user fees match costs, they usually have overlooked how pricing could enhance the benefits of their size and weight regulatory proposals. Performance standards and pricing could help filter out undesirable trucks that might manage to comply with the dimensional limits but would be inconsistent with the principles of economy and safety that are supposed to justify the limits.
U.S. Department of Transportation
Health Effects Institute
Interstate Commerce Commission
North American Free Trade Agreement Land Transportation Standards Subcommittee
National Research Council
National Road Transport Commission
Roads and Transportation Association of Canada
Transportation Research Board
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