Almost all of the paved roads in the nation are paved with asphalt. However, asphalt is made from oil! It is the lowest grade part of crude oil. After removing all of the fuel components, the remainder becomes asphalt.
The increase of the price of crude oil has brought along with it an increase in asphalt price. That coupled with the current economic crisis means that the states and counties charged with overseeing and maintaining the bulk of the nations' roads are not able to keep them paved. For example, in Michigan, 20 of the 83 counties in that state have converted paved roads in bad shape to gravel. Northern states will generally have the most trouble because the freeze-thaw cycles are hard on pavement.
Another feedback on all this is that gravel roads induce worse fuel economy. Vehicles will use the fewest gallons per hundred miles when driving on the smoothest, most level roads. Gravel roads have more friction that smooth paved ones. Thus as high oil prices lead to high asphalt prices, more and more roads will convert to gravel. That will cause the vehicles that use those roads to burn more gasoline, which will in turn lead to yet more upwards pressure on the price of crude.
The half century of happy motoring the the US is drawing to a close. The signs are all around; from the historically high and persistent price of crude oil, to the reversion of paved roads to gravel to the introduction of the Tata Nano in India. It is difficult to see how over the next decade or so we can possibly avoid a world where driving is expensive and more difficult.