Federal regulators approved the first increase in US fuel economy regulations in nine years on Tuesday, requiring vehicle makers to increase the average fuel efficiency of light trucks by 1.5 miles per gallon by 2007, the Detroit News reported. The paper said the new regulation --first proposed in December -- will require light truck fleets to average 21.0 mpg in the 2005 model year, 21.6 mpg in 2006 and 22.2 mpg in 2007. Currently, light trucks must average 20.7 mpg.