According to reports, the Bush administration is expected to propose a plan that would set multiple fuel economy standards for light trucks according to their size but not weight.

The proposal, developed by the National Highway Traffic Safety Administration (NHTSA) and now being reviewed by the Secretary of Transportation, would apply to pickup trucks, SUVs and vans beginning as early as the 2008 model year. According to sources, the proposal’s details are still being ironed out, including exactly how to group the trucks.

The current corporate average fuel economy (CAFE) standard requires each OEM to meet a single sales weighted truck fleet average, currently at 21 mpg and rising to 22.2 mpg by 2007.

Four years ago, the National Academy of Sciences suggested that trucks be grouped into several weight categories and adhere to stricter fuel economy standards.