Setting the stage for regulation of heavy-duty vehicle fuel economy and GHG emissions

This document discusses issues related to the regulation of fuel efficiency of heavy-duty vehicles in the United States. While new U.S. light-duty vehicles (cars and light trucks) are required to meet minimum corporate average fuel economy standards, medium and heavy-duty vehicles (larger trucks and buses) are not. There are currently no federal standards for the fuel economy of large trucks and buses, either for individual models or as a fleet average.

The current U.S. heavy-duty vehicle (HDV) fleet is extremely diverse, in terms of vehicle size and configuration, as well as usage patterns. It encompasses everything from 18-wheel combination trucks used to haul freight, to school and transit buses, to numerous “vocational” trucks such as refuse haulers, utility service trucks, and dump trucks. The largest of these vehicles – combination trucks comprised of a truck-tractor pulling a trailer – typically weight 80,000 pounds or more. In 2005 the 8.5 million heavy-trucks registered in the U.S. traveled over 222 billion miles and emitted almost 350 million metric tons of carbon dioxide to the atmosphere – approximately 19% of the CO2 emissions from all transportation sources.
The development of effective fuel efficiency and GHG regulations for HDVs will require attention to numerous technical and policy-related details. Decisions as to the “best” regulatory design must be based on a thorough understanding of existing and future characteristics of the HDV fleet, the structure and characteristics of the HDV manufacturing industry, and potential technology approaches available to reduce HDV fuel use and GHG emissions.
The technical issues that must be addressed range from the metric used to measure fuel economy or GHG emissions, to the format of required improvements, to the test method used to verify compliance. Policy-related issues that can significantly affect the implementation cost and the effectiveness of the regulations include: specific vehicle types to be regulated, companies responsible for compliance, the implementation timeline, provisions for compliance flexibility, and methods of enforcement.
For each technical and policy area there are a number of options available to policymakers. Different approaches will have different potential benefits, costs, and implementation issues. The optimal regulatory design will balance these different implementation issues to achieve cost-effective improvements.
This document is intended to set the stage for an effective and productive dialogue about the optimal regulatory design for HDV fuel efficiency and GHG improvements. The first six chapters provide background information about the composition of the U.S. HDV fleet and the structure of the HDV manufacturing industry; major factors that contribute to fuel use by HDVs; current voluntary efforts and regulatory requirements to increase HDV fuel efficiency in the U.S., Japan, and the European Union; and the technology options available to improve HDV fuel efficiency. The remainder of the document discusses specific technical and policy issues that must be addressed in the design of HDV fuel efficiency and GHG regulations, barriers to implementing these regulations in the U.S., related policy issues, and recommendations for further research and analysis.