The National Highway Transportation Safety Administration (NHTSA) released its proposed regulations for Corporate Average Fuel Economy (CAFE) standards increases through 2015. The proposed rulemaking raises required average highway mileage to 35.7 mpg for passenger cars and 28.6 mpg for light trucks. The improved fuel economy would also address climate change by reducing tailpipe emissions of carbon dioxide, which represent 97 percent of total greenhouse gas emissions from motor vehicles. The proposed regulations also increase the applicable life of fleet credits from three to five years and allows trading them between vehicle classes as well as among manufacturers.

This document is being issued pursuant to the Energy Independence and Security Act of 2007 (EISA), which Congress passed in December 2007. EISA mandates the setting of separate maximum feasible standards for passenger cars and for light trucks at levels sufficient to ensure that the average fuel economy of the combined fleet of all passenger cars and light trucks sold by all manufacturers in the U.S. in model year (MY) 2020 equals or exceeds 35 miles per gallon. That is a 40 percent increase above the average of approximately 25 miles per gallon for the current combined fleet.

Congress enables NHTSA to require these substantial increases in fuel economy by requiring that passenger car standards be reformed through basing them on one or more vehicle attributes. The attribute-based approach was originally recommended by the National Academy of Sciences in 2002 and adopted by NHTSA for light trucks in 2006. The new approach is a substantial improvement over the old approach of specifying the same numerical standard for each manufacturer by avoiding undue risks of adverse safety and employment impacts on vehicle manufacturers.