A Better Gas Tax

Josh Barro designs one. He wants to index it to inflation:

The gas tax was last raised in 1993, and has fallen by a third in real terms since. Many state gas taxes and other vehicle taxes have also fallen in real terms. But this has not led to lower spending on road construction and maintenancefrom 1994 to 2008, while GDP grew 103 percent and road spending grew 102 percent, gas and vehicle tax receipts rose only 70 percent.

Governments have made up the difference by tripling their borrowing to finance roads and tripling the diversion of general revenue to pay for road costs. This is a bad trend, because gas taxes below the cost of roads use cause inefficient overuse of roads, and the higher sales and income taxes used to plug the gas tax gap are a drag on the economy. Real annual reductions in gas tax rates hasn't starved the beast, but have made the way we pay for our road infrastructure less efficient.