The uncertainty surrounding federal highway and transit funding received a respite through the rest of this year when the Senate voted to pass the $18 billion Hiring Incentives to Restore Employment Act, followed by President Obama signing it into law. This follows a series of continuing resolutions—or extensions—to keep funding afloat at current spending levels, following the September 2009 expiration of SAFETEA-LU. This measure also ensures that the Highway Trust Fund (HTF) remains solvent during that period through a $19.5 billion transfer from the United States General Trust Fund. The HTF is the federal government's primary source for financing highway, bridge, and transit projects, according to the DOT. It's largely financed by the federal motor fuel tax, which is 18.4 cents per gallon for gasoline and 24.4 percent for diesel, and has not been raised since 1993.