DETROIT (AP) — 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. GM, the nation’s largest automaker, spelled out the request Friday in written comments on a Trump administration proposal to roll back Obama-era fuel economy and emissions standards, freezing them at 2020 levels instead of gradually making them tougher. California Gov. Jerry Brown, whose state was one of many opponents to the mileage rollbacks filing objections to the Trump plan, stood in front of Interstate 5 in Sacramento on Friday to urge the cause of cleaner cars and condemn the administration’s proposal. “Foolishly, it mandates gas guzzlers instead of clean and zero-emission vehicles,” Brown told reporters as trucks and passenger traffic roared past. “Wrong way to go, Donald….