|Greenhouse gas and fuel economy levels under the EPA NHTSA joint proposed rulemaking. Click to enlarge.|
The US Department of Transportation (DOT) National Highway Traffic Safety Administration (NHTSA) and the US Environmental Protection Agency (EPA) jointly proposed a rule establishing a national program that would improve vehicle fuel economy and reduce greenhouse gases. The proposal builds upon the core principles President Obama announced in May for a harmonized national policy intended to reduce fuel consumption and greenhouse gas (GHG) emissions for all new cars and trucks sold in the US.(Earlier post.)
In this joint rulemaking, EPA and NHTSA are proposing two separate sets of attribute-based standards applying to passenger cars, light-duty trucks, and medium-duty passenger vehicles, covering model years 2012 through 2016, each under its respective statutory authorities:
EPA is proposing national CO2 emissions standards for light-duty vehicles under section 202 (a) of the Clean Air Act. These standards would require these vehicles to meet an estimated combined average emissions level of 250 grams/mile of CO2 in model year 2016.
NHTSA is proposing CAFE standards for passenger cars and light trucks under 49 U.S.C. 32902. These standards would require them to meet an estimated combined average fuel economy level of 34.1 mpg in model year 2016.
There is a difference in stringency for the two standards due to differences in the agencies’s respective statutory authorities. EPA expects manufacturers to take advantage of the option to generate CO2-equivalent credits by reducing emissions of hydrofluorocarbons (HFCs) and CO2 through improvements in their air conditioner systems. EPA accounted for these reductions in developing its proposed CO2 standard. However, EPCA does not allow vehicle manufacturers to use air conditioning credits in complying with CAFE standards.
The 250 g/mile of CO2 equivalent emissions limit by EPA is equivalent to 35.5 mpg if the automotive industry were to meet this CO2 level all through fuel economy improvements. As a consequence of the prohibition against NHTSA’s allowing credits for air conditioning improvements for purposes of passenger car CAFE compliance, however, NHTSA is proposing fuel economy standards that are estimated to require the combined (passenger car and light truck) average fuel economy level of 34.1 mpg by MY 2016.
The proposed standards for both agencies begin with the 2012 model year, with standards increasing in stringency through model year 2016. They represent a harmonized approach that will allow industry to build a single national fleet that will satisfy both the GHG requirements under the CAA and CAFE requirements under EPCA/EISA.
NHTSA and EPA worked closely to develop their respective proposals comprising the National Program. The agencies developed a comprehensive joint Technical Support Document (TSD) that provides a technical underpinning for each agency’s modeling and analysis used to support the proposed standards. Also, to the extent allowed by law, the agencies have harmonized many elements of program design, such as the form of the standard (the footprint-based attribute curves), and the definitions used for cars and trucks.
They have developed the same or similar compliance flexibilities, to the extent allowed and appropriate under their respective statutes, such as averaging, banking, and trading of credits, and have harmonized the compliance testing and test protocols used for purposes of the fleet average standards each agency is proposing.
EPA and NHTSA expect that automobile manufacturers will meet these proposed standards by utilizing technologies that will reduce vehicle GHG emissions and improve fuel economy. Although many of these technologies are available today, the emissions reductions and fuel economy improvements proposed would involve more widespread use of these technologies across the light-duty vehicle fleet.
These include improvements to engines, transmissions, and tires, increased use of start-stop technology, improvements in air conditioning systems (to the extent currently allowed by law), increased use of hybrid and other advanced technologies, and the initial commercialization of electric vehicles and plug-in hybrids. Together, EPA and NHTSA estimate that the average cost increase for a model year 2016 vehicle due to the proposed National Program is less than $1,100.
The light-duty vehicles subject to this proposed National Program account for about 40% of all US oil consumption, and about 60% of transportation sector oil use. The combined EPA and NHTSA standards would reduce carbon dioxide emissions from the light-duty vehicle fleet by about 21% in 2030 over the level that would occur in the absence of any new greenhouse gas or fuel economy standards. The greenhouse gas emission reductions this program would bring about are equivalent to the emissions of 42 million cars.
NHTSA has prepared a Draft Environmental Impact Statement (EIS) for the proposed CAFE standards. The Draft EIS compares the environmental impacts of the agency’s proposal and reasonable alternatives.
NHTSA and EPA are providing a 60-day comment period on the proposed rulemaking that begins with publication of the proposal in the Federal Register. NHTSA is providing a 45-day comment period on the Draft EIS. The proposal and information about how to submit comments are here for EPA and here for NHTSA.