A panel of outside experts advising federal regulators about available technologies for improving fuel economy will include light-duty diesel engines for the first time in its final report, according to Autoweek. The panel said Wednesday that recent developments in emission controls indicate modern diesels will be able to comply with U.S. clean-air regulations.

"The potential of diesel engines to reduce fuel consumption by as much as 30 to 40 percent over comparable gasoline engines justifies their inclusion on the list of available technologies," the interim report said. An earlier version of this same study was what led Congress to consider CAFE requirements through 2011, and eventually helped spur new legislation raising CAFE to 35 mpg by the 2020 model year.

The updated study, which hasn't seen a revamp since 2001, will now also include hybrids as well—back then hybrids were considered a niche technology, and diesels couldn't meet emissions standards. Autoweek said that the report will not deal extensively with all-electric or fuel cell vehicles because "the committee does not expect commercialization of fuel cell vehicles or widespread marketing of all-electric vehicles before 2020."

Photo credit: Mercedes E300 Bluetec / Daimler Global Media