The vast majority of federal surface transportation funding—nearly 90 percent in 2007— is provided through the HTF. The remainder is appropriated from the General Fund of the U.S. Treasury, primarily for transit capital and preventive maintenance spending.15 The HTF initially was authorized by the Highway Revenue Act of 1956 to account for the collection of certain federal highway user taxes on motor fuels and vehicles and to ensure a dependable source of funding for financing the National System of Interstate and Defense Highways and other major highways. In 1983, in conjunction with a major federal motor fuel tax increase, Congress deter- mined that proceeds from 1¢ per gallon on gasoline and diesel should be dedicated to fund transit and established a Mass Transit Account within the HTF. The Mass Transit Account allocation was subsequently increased three times and is currently 2.86¢ per gallon.16 Since 1956, periodic legislation has extended and occasionally increased the taxes that fund the HTF. The Safe, Account- able, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) signed into law in August 2005 extended the HTF and its associated taxes through Fiscal Year (FY) 2011.