Draft Regulatory Impact Analysis: Proposed Rulemaking to Establish Greenhouse Gas Emissions Standards for Medium- and Heavy-Duty Engines and Vehicles

In July 2010, the National Research Council (NRC) appointed the Committee to Review the 21st Century Truck Partnership, Phase 2, to conduct an independent review of the 21st Century Truck Partnership (21CTP). The 21CTP is a cooperative research and development (R&D) partnership including four federal agencies-the U.S. Department of Energy (DOE), U.S. Department of Transportation (DOT), U.S. Department of Defense (DOD), and the U.S. Environmental Protection Agency (EPA)-and 15 industrial partners. The purpose of this Partnership is to reduce fuel consumption and emissions, increase heavy-duty vehicle safety, and support research, development, and demonstration to initiate commercially viable products and systems. This is the NRC's second report on the topic and it includes the committee's review of the Partnership as a whole, its major areas of focus, 21CTP's management and priority setting, efficient operations, and the new SuperTruck program.

Technologies and Approaches to Reducing the Fuel Consumption of Medium- and Heavy-Duty Vehicles evaluates various technologies and methods that could improve the fuel economy of medium- and heavy-duty vehicles, such as tractor-trailers, transit buses, and work trucks. The book also recommends approaches that federal agencies could use to regulate these vehicles' fuel consumption. Currently there are no fuel consumption standards for such vehicles, which account for about 26 percent of the transportation fuel used in the U.S. The miles-per-gallon measure used to regulate the fuel economy of passenger cars. is not appropriate for medium- and heavy-duty vehicles, which are designed above all to carry loads efficiently. Instead, any regulation of medium- and heavy-duty vehicles should use a metric that reflects the efficiency with which a vehicle moves goods or passengers, such as gallons per ton-mile, a unit that reflects the amount of fuel a vehicle would use to carry a ton of goods one mile. This is called load-specific fuel consumption (LSFC). The book estimates the improvements that various technologies could achieve over the next decade in seven vehicle types. For example, using advanced diesel engines in tractor-trailers could lower their fuel consumption by up to 20 percent by 2020, and improved aerodynamics could yield an 11 percent reduction. Hybrid powertrains could lower the fuel consumption of vehicles that stop frequently, such as garbage trucks and transit buses, by as much 35 percent in the same time frame.

This research report examines the economic and environmental externalities associated with the US transportation sector. The United States currently accounts for about 25 percent of world oil consumption, about 50 percent of which is imported. Achieving energy security by reducing dependence on imported oil has been the foremost challenge of several major energy-importing countries, including the United States. In this study, we explored the costs associated with energy security/cost of dependence on oil and estimated the environmental externalities associated with different types of transportation fuels based on a set of economic, environmental, and life-cycle analysis models. Our assessment of estimations on oil dependence costs indicates that several elements constitute the true cost of oil and not many studies have attempted to include all of these costs for various reasons. For analyzing the environmental externalities, we used a life-cycle analysis model; the FASOM-GHG model of agriculture and forestry; APEEP—an integrated assessment model to calculate the marginal damage of emissions; GTAP-BIO—a computable general equilibrium model to estimate land use changes; and the OSIRIS model to estimate the species extinctions based on deforestation. This study on assessing the externalities could provide a quantitative basis for policy initiatives pertaining to America’s future transportation infrastructure. This study suggests that there is a need to consider economic, environmental, and other societal costs within a holistic framework to assess relative costs and benefits and suitability of alternative transportation fuels that could play a role in meeting our future energy needs.