Make fuel economy standards truly “fuel neutral.”
Since Corporate Average Fuel Economy (CAFE) gives credit to vehicles based on fuel economy rather than oil use, and a gallon of low-sulfur diesel fuel requires 25 percent more oil than a gallon of low-sulfur reformulated gasoline, putting more diesel vehicles on the road without also raising fuel economy standards could actually increase U.S. oil dependence. CAFE standards should, at a minimum, compare gasoline and diesel on an energy-equivalent basis.
# What is CAFE?

Corporate Average Fuel Economy (CAFE) is the sales weighted average fuel economy, expressed in miles per gallon (mpg), of a manufacturer’s fleet of passenger cars or light trucks with a gross vehicle weight rating (GVWR) of 8,500 lbs. or less, manufactured for sale in the United States, for any given model year. Fuel economy is defined as the average mileage traveled by an automobile per gallon of gasoline (or equivalent amount of other fuel) consumed as measured in accordance with the testing and evaluation protocol set forth by the Environmental Protection Agency (EPA).
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soot-is a dark powdery deposit of unburned fuel residues, usually composed mainly of amorphous carbon, that accumulates in chimneys, automobile mufflers insides of smoke saunas and other surfaces exposed to smoke—especially from the combustion of carbon-rich organic fuels in the lack of sufficient oxygen.