SAN FRANCISCO — A federal appeals court here rejected the Bush administration’s year-old fuel-economy standards for light trucks and sport utility vehicles on Thursday, saying that they were not tough enough because regulators had failed to thoroughly assess the economic impact of tailpipe emissions that contribute to climate change. A three-judge panel of the Ninth Circuit Court of Appeals, in San Francisco, voided the new regulations for 2008-2011 model year vehicles and told the Transportation Department to produce new rules taking into account the value of reducing greenhouse gas emissions. The court, siding with 4 environmental groups and 13 states and cities, also asked the government to explain why it still treated light trucks - which include pickups, sport utility vehicles and minivans - more mildly than passenger cars. Under the rejected rule, the average fuel economy of light trucks was to rise to 23.5 miles a gallon in 2010, up from the current standard of 22.5 m.p.g., but still well below the current standard for passenger cars of 27.5 m.p.g. The ruling, which is likely to be appealed to the United States Supreme Court, represents a major setback for both the auto industry and the […]