The Environmental Protection Agency is slapping down California's bid for first-in-the-nation greenhouse gas limits on cars, trucks and SUVs.
The agency today denied the state's request for a waiver that would have allowed those restrictions to take effect.
The head of the EPA said the Bush administration wants a national solution rather than a "patchwork" of state rules.
The long-awaited decision amounted to a serious setback for California and 16 other states seeking the new car regulations to achieve their anti-global warming goals.
At issue were tailpipe standards California adopted in 2004 that would have forced automakers to cut greenhouse gas emissions by 30 percent in new cars and light trucks by 2016.