Fuel economy standards could change for the first time in six years if a Bush administration proposal to modestly increase gas mileage in sport utility vehicles, vans, minivans, and pickup trucks is approved. The proposal would increase the fuel economy of those vehicles by 1.5 miles per gallon over three years, beginning in 2005, from the current standard of 20.7 mpg to 22.2 mpg. (The standard of 27.5 mpg for passenger cars would remain unchanged.) In total, the change would save about 2.5 billion gallons of gasoline per year, according to the U.S. Department of Transportation. Some Democrats and environmentalists criticized the proposal as too little, too late, and accused the Bush administration of missing a critical opportunity to limit dependence on foreign oil and reduce U.S. greenhouse gas emissions, one-fifth of which come from cars and light trucks. “The administration is merely ratifying less than what industry is already doing on its own without challenge or incentive,” said Sen. John Kerry (D-Mass.), who was the cosponsor of an unsuccessful measure to increase fuel economy standards for all vehicles to 36 mpg by 2015.