California long has been the pacesetter in regulating car emissions, setting tougher limits than those imposed by the federal government.
To avoid having cars built to meet 50 different sets of state rules, federal law allows other states to choose between the federal and the California rules. Vermont and nine other states follow California.
But on Tuesday, the focus shifts to Vermont, where a trial begins over new rules — adopted by California in 2005 and soon after by the other states — designed to reduce emissions of the greenhouse gas carbon dioxide.
The trial, resulting from a lawsuit filed against Vermont by a coalition of automakers and car dealers, is the first of a series of court fights expected in the states.
“Vermont is the first court in the nation to decide this issue and that will potentially have enormous impact,” said Melissa Hoffer, vice president of the Conservation Law Foundation, one of several environmental groups involved in the case.
Charles Territo, spokesman for the Alliance of Automobile Manufacturers, called the case “very important, because it’s the first trial where the issue of whether or not states have the authority to set their own fuel economy standards will be decided.”
At issue is which set of federal regulations will control vehicle carbon emissions.
The auto industry argues that the only way to reduce carbon emissions is to improve vehicle mileage, because carbon emissions depend on how much fuel is burned. The U.S. Department of Transportation sets fuel economy standards; federal law — the Energy Policy and Conservation Act — pre-empts states from doing so.