Lengths, and Widths of Commercial Motor Vehicles, Special Report 267 (TRB, 2002).

  • Consider the necessary changes that would be required to permit reasonable access of LCVs to vehicle breakdown yards and major shipping facilities in close proximity to the interstate.

Recommendation 7-2. Congress should give serious consideration to liberalizing weight and size restrictions and should consider how the potential fuel savings and other benefits of such liberalization can be realized in a way that maintains safety and minimizes the cost of potential infrastructure changes.

Finding 7-10. Intelligent transportation systems enable more efficient use of the existing roadway system by improving traffic flow and reducing or avoiding congestion.

Finding 7-12. There are significant opportunities for savings in fuel, equipment, maintenance, and labor when drivers are trained properly. Indications are that this could be one of the most cost-effective and best ways to reduce fuel consumption and improve the productivity of the trucking sector. For example, cases evaluated herein demonstrate potential fuel savings of ~2 to 17 percent with appropriately trained drivers.

Recommendation 7-3. The federal government should encourage and incentivize the dissemination of information related to the relationship between driving behavior and fuel savings. For example, one step in this direction could be to establish a curriculum and process for certifying fuel-saving driving techniques as part of commercial driver license certification and to regularly evaluate the effects of such a curriculum.


This is an important juncture for the nation. The choices that will be made over the course of the next few years will establish the regulatory design for MHDV fuel consumption standards for the next several decades at least. While the stringency of the standards themselves may be revisited from time to time, the regulatory design elements (regulated parties, certification tests and procedures, compliance methods)—once established—are far more difficult to modify.

In many cases, the commercial vehicle market is sophisticated, driven by knowledgeable purchasers who focus on the efficiency of their operations, including the fuel costs associated with accomplishing their tasks. Thus, one of the most important challenges facing NHTSA is how to enhance and improve upon the commercial trucking industry’s existing desire to maximize the fuel economy of its trucks and fleets.

At the same time, there are commonly acknowledged characteristics in the commercial truck and buses market-place that may be improved by a regulatory approach, such as split incentives between owners and operators (e.g., trailers) and the short payback period of 18 months to 2 years, that create barriers to the adoption of efficiency technologies for many purchasers, suggesting that a well-designed regulatory program may yield important benefits.

Due to the complexity of the vehicle market, the committee was not able to give adequate consideration to the non-commercial markets such as personal pickup trucks, school buses, and personal motor homes. NHTSA should consider these applications in its regulatory proposal.

A fundamental concern raised by the committee and those who testified during its public sessions was the tension between the need to set a uniform test cycle for regulatory purposes and existing industry practices of seeking to minimize fuel consumption of medium- and heavy-duty vehicles designed for specific routes that may include grades, loads, work tasks, or speeds inconsistent with the regulatory test cycle. This concern emphasizes the critical importance of achieving fidelity between certification values and real-world results, in order to avoid driving decisions that hurt rather than help real-world fuel consumption.

Because regulations can lead to unintended consequences, either because the variability of tasks within a vehicle class is not adequately dealt with or because regulations may lead to distortions between classes in the costs of accomplishing similar tasks, the committee urges NHTSA to carefully consider all factors when developing its regulatory proposal.

Major Finding and Recommendations—Chapter 8

Finding 8-1. While it may seem expedient to focus initially on those classes of vehicles with the largest fuel consumption (i.e., Class 8, Class 6, and Class 2b, which together account for approximately 90 percent of fuel consumption of MHDVs), the committee believes that selectively regulating only certain vehicle classes would lead to very serious unintended consequences and would compromise the intent of the regulation. Within vehicle classes, there may be certain subclasses of vehicles (e.g., fire trucks) that could be exempt from the regulation without creating market distortions.

Finding 8-2. Large original equipment manufacturers (OEMs), which have significant engineering capability, design and manufacture almost all Class 2b, 3, and 8b vehicles. Small companies with limited engineering resources make a significant percentage of vehicles in Classes 4 through 8a, although in many cases they buy the complete chassis from larger OEMs. Regulators will need to take the limitations of these smaller companies into account.

Finding 8-3. Commercial trailers are produced by a separate group of manufacturers that are not associated with truck

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