Senator John McCain of Arizona, the ranking Republican on the Senate Commerce Committee, introduced a bill on Feb. 7 that calls for an increase of up to 50 percent in automotive fuel economy standards by 2016, according to the New York Times. The bill also proposes closing the gap between standards set for passenger cars and light trucks, an issue that has been a chief concern of environmental groups. And it seeks a complicated trading system that would permit automakers to swap credits for reducing greenhouse gas emissions with companies in other industries. Sen. McCain's proposals are not as ambitious as those in a similar fuel economy bill submitted today by the Democratic leaders of the Commerce Committee, John Kerry of Massachusetts and Committee Chairman Ernest F. Hollings of South Carolina. But coming as it does from a leading Republican, the McCain bill is seen by political analysts as a setback for the auto industry, which has lobbied to allow the petroleum-friendly Bush administration, not Congress, to decide what action to take on fuel economy standards and has resisted any big increase of current requirements.