California Gov. Gray Davis on July 22, 2002 signed a landmark bill making the state the first in the nation to regulate the vehicle greenhouse gas emissions scientists say contribute to global warming. The legislation, which has been opposed by the auto industry, requires the California Air Resources Board to adopt regulations that would achieve "the maximum feasible reduction" in emissions of greenhouse gases, including carbon dioxide, emitted by cars and light-duty trucks, the category that includes sport/utility vehicles. The regulations, which should be completed by 2005, would not take effect until Jan. 1, 2006. The amended version of the new law also gives automakers until 2009 to come up with technological changes or modifications to comply with the new standards. With California making up some 10 percent of the national auto market, state officials say the new legislation could become a national model and will push automakers to devise new ways to make cars and trucks run cleaner. Auto industry groups have criticized the law, which they say will bring almost no environmental benefits while penalizing California drivers of light trucks and SUVs, which now account for some 47 percent of passenger vehicles sold in the state.