|Historical and projected achieved fuel economy (mpg US) for passenger cars and light trucks. Source: NHTSA Final EIS. Click to enlarge.|
The US National Highway Traffic Safety Administration (NHTSA) has issued the final Environmental Impact Statement (EIS) for the proposed CAFE standards for model years 2017-2025 (Earlier post.) The US Environmental Protection Agency (EPA) and NHTSA have been working together on developing the National Program of harmonized regulations to reduce greenhouse gas emissions and improve fuel economy.
NHTSA and EPA issued a joint notice of proposed rulemaking (NPRM) in November 2011 on the 2017–2025 program; NHTSA proposed CAFE standards to require, on an average industry fleet-wide basis for cars and trucks combined, approximately 40.1 mpg US (5.87 L/100km) in model year 2021, and 49.6 mpg (4.74 L/100km) in model year 2025. The agency also issued a draft EIS at that time.
In any single rulemaking under the Energy Policy and Conservation Act of 1975 (which established the CAFE program), fuel economy standards may be established for not more than 5 model years. For this reason, NHTSA’s proposal is limited to setting standards for MYs 2017–2021. In the NPRM, NHTSA also set forth values for MYs 2022–2025 that reflected the agency’s estimate of the standards it would have proposed and adopted had it the authority to do so. Actual CAFE standards for MYs 2022–2025 will be proposed in a subsequent rulemaking process.
However, because NHTSA’s effort is part of a joint NHTSA/EPA rulemaking for a coordinated and harmonized National Program covering MYs 2017–2025, this EIS addresses the potential impacts of the proposed standards for MY 2017–2021 and the values set forth for MYs 2022–2025 for each of the alternatives, thus covering the full MY 2017–2025 period.
The newly released final NHTSA EIS compares the potential environmental impacts of four alternative approaches to regulating light‐duty vehicle fuel economy for MYs 2017–2025, including a Preferred Alternative and a No Action Alternative, using two different assumptions regarding market‐driven fuel economy improvements and two different sets of fleet characteristic assumptions.
The four action alternatives are:
A 2% average annual fleet-wide increase in fuel economy for both passenger cars and light trucks for MYs 2017–2025. Alternative 2 represents the lower bound of the range of annual stringency increases NHTSA believes includes the maximum feasible stringency.
Preferred. Under the Preferred Alternative, manufacturers would be required to meet an estimated average fleet-wide fuel economy level of 40.3 to 41.0 mpg in MY 2021 and 48.7 to 49.7 mpg in MY 2025.
These averages are uncertain, because the actual average required fuel economy levels in the future will depend upon the actual composition of the future fleet, which can only be estimated—with considerable uncertainty—at this time, NHTSA said.
The proposed stringency increases to the attribute‐based standards (i.e. the target functions as expressed on a gallons per mile [gpm] basis) for MYs 2017–2021 average 3.6% for passenger cars.
In recognition of manufacturers’ unique challenges in improving the fuel economy and GHG emissions of full‐size pickup trucks while preserving the utility of those vehicles, NHTSA’s proposal includes a slower annual rate of improvement for light trucks in the first phase of the program. The proposed stringency increases to the attribute‐based standards for MYs 2017–2025 average 2.3% (on a gpm basis) for light trucks.
For MYs 2022–2025, the annual stringency increases set forth average 4.4% (also on a gpm basis) for both passenger cars and light trucks. The target curves identified as the Preferred Alternative and analyzed in this Final EIS are the same as those that defined the Preferred Alternative in the Draft EIS and outlined as the proposal in the NPRM. In other words, the rate of increase in stringency of the Preferred Alternative analyzed in the Final EIS has not changed.
A 7% average annual fleet-wide increase in fuel economy for both passenger cars and light trucks for MYs 2017–2025. Alternative 4 represents the upper bound of the range of annual stringency increases NHTSA believes includes the maximum feasible stringency.
The EIS describes how the alternatives could affect energy use; air quality; and climate. The EIS also qualitatively describes potential additional impacts on water resources, biological resources, hazardous materials and regulated wastes, noise, and environmental justice.