David Friedman, an auto expert with the non-profit organization, said he would propose that requirement Friday during a House Financial Services Committee on government aid to the automakers.

Such a link would provide a return on return on taxpayer investment, strengthen the industry, reduce U.S. oil dependence and help mitigate global warming, the union said in a news release Thursday.

Automakers and other concerned entities testified before a Senate panel Thursday.

"U.S. automakers are promising Congress they will make better cars and stay competitive," Friedman said. "But Congress can't just take their word for it and cut a blank check. If the automakers say they can make more fuel efficient cars with the money, they ought to be required, by law, to deliver on that promise."