It seems the price-induced reductions in miles driven we're experiencing is significant enough that it's producing a shortfall in gas tax money going into the Highway Trust Fund. In response, I would note that John McCain's call for a gas tax "holiday" seems likely to exacerbate this problem significantly. On top of that, it seems to me that this would be an opportune moment to revisit some of our national priorities. With Trust Fund revenue falling, we ought to dedicate what remains to maintaining our existing road infrastructure but stop funding new highway projects.
Instead, general revenues can and should be used to pay for substantial increases in the quantity and quality of non-car transportation options. After all, the striking thing about the modest decline in driving that we've seen in 2008 is that it's happened even though essentially no effort has been put into providing anyone with reasonable alternatives. Insofar as state and local governments have responded at all, it's tended to be by cutting back on rail and bus service to save money at a time when the economic slowdown is hurting state budgets and the federal government is acting cluelessly.
New rail lines would, obviously, take time to build. But one could easily enough increase frequency and decrease fares on bus lines all across the country as a short-term measure. And there are a lot of commuter rail lines around the country that could have their non-rush hour frequency boosted in the short run. And of course we ought to be planning for the long run. Right now, only a smallish minority of Americans have access to decent quality alternatives to daily driving but it doesn't need to be that way and we shouldn't leave ourselves this exposed to future energy shocks.
Photo by Flickr user Rene S used under a Creative Commons license