Recently passed legislation in California has the potential to transform national policies on fuel economy and emissions. The measure will stand if Gov. Gray Davis signs the bill. Auto manufacturers are attempting to prove that the measure is an attempt to set fuel economy standards. Environmental groups are eager to establish the idea that states have the authority to regulate carbon dioxide as a pollutant. The automakers fear the only practical way to reduce carbon dioxide emissions is to stop selling SUVs and pickups, both sources of high revenue. The California Legislature approved the bill June 29 and July 1, in spite of lobbying and advertising against it. Proponents of the bill claim industry groups may have spent as much as $10 million on this campaign.