23 April 2008

The US US Department of Transportation’s (DOT) National Highway Traffic Safety Administration proposed increased Corporate Average Fuel Economy (CAFE) standards for passenger cars and light trucks. The standards increase by 4.5% per year over the five-year period ending in 2015, which represents a 25% total improvement compared to current standards.

For passenger cars, the proposal would increase fuel economy from the current 27.5 mpg to 35.7 mpg by 2015. For light trucks, the proposal calls for increases from 23.5 mpg in 2010 to 28.6 mpg in 2015.

Under the proposal, CAFE standards would be adopted for each vehicle manufacturer, based on target levels of average fuel economy set for vehicles of different sizes and the distribution of that manufacturer’s vehicles among those sizes. Size would be defined by vehicle footprint (track width × wheelbase). Thus, the exact standards depend on the actual vehicle mix sold by a manufacturer in a given year. NHTSA projections for the industry-wide fuel economy targets are summarized in the following table.

Proposed Average Optimized Fuel Economy Targets, MY 2011-2015
(CO2 rates based on gasoline characteristics)
MY Cars Trucks Combined
mpg gCO2/mi mpg gCO2/mi mpg gCO2/mi
2011 31.2 285 25.0 355 27.8 320
2012 32.8 271 26.4 337 29.2 304
2013 34.0 261 27.8 320 30.5 291
2014 34.8 255 28.2 315 31.0 287
2015 35.7 249 28.6 310 31.6 281

While the CO2 figures in the table are based on gasoline engine characteristics, it can be reasonably anticipated that auto manufacturers will meet the increased standards—among other measures—through increased sales of diesel vehicles.

Under the Energy Independence and Security Act of 2007 (EISA), fuel economy standards must be adopted to ensure that the average fuel economy of the combined fleet of all passenger cars and light trucks sold in the United States by 2020 equals or exceeds 35 mpg—a 31% increase above the 2007 new fleet average of 26.7 mpg. The proposed rulemaking covers model years 2011-2015, as under EISA the NHTSA can establish standards for a maximum of five model years at a time.

Source: NHTSA (Press release | Notice of proposed rulemaking)