> The reason is, that in many cases, the fuel taxes collected are far, far in excess of the money actually spent in maintaining the road and building new roads.

Actually, you have this backwards[1]. The cost of maintaining roads exceeds the revenues generated by gas taxes.

In fact, the only transportation 'use tax' account that consistently runs a surplus is the federal Airport Improvement Trust Fund.

[1] First hit on the Google: http://www.governing.com/topics/transportation-infrastructur...