The states should stop sending money to DC altogether.
Who writes the check to pay for gasoline taxes (yes, I know the drivers really pay it)? Is it every gas station? The distributors? The refiners?
Do they write a check directly to the federal government or do they pay their own states who then send the federal portion to Washington?
Other than maybe a penny or two to pay for roads necessary for defense but not used much by the locals (Alaska is the only place left like that I can think of), I see no reason why the taxing and paying for roads shouldn't be left entirely to the states. The primary use of federal gas taxes now is to force states to put in rules on blood alcohol limits, speed limits, seat belts, helmets and even capitalization and typeface selection of road signs that the Constitution doesn't allow the federal government to regulate directly.