GM proposes nationwide zero-emissions vehicle sales mandate

General Motors says it will ask the federal government for one national gas mileage standard, including a requirement that a percentage of auto companies' sales be zero-emissions vehicles.  Mark Reuss, GM's executive vice president of product development, said the company will propose that a certain percentage of nationwide sales be made up of vehicles that run on electricity or hydrogen fuel cells."A national zero emissions program will drive the scale and infrastructure investments needed to allow the U.S. to lead the way to a zero emissions future," Reuss said.