A new study by a national transportation research group recommends raising fuel taxes to generate revenue to fix the nation's overcrowded highways. An increase in the current federal highway tax of 18.4 cents per gallon was one of the recommendations in a report by The Road Information Program (TRIP) of Washington, D.C.

The study noted that the nation's interstate highway system has exceeded its capacity, jeopardizing the system's safety and its economic benefits. TRIP noted that similar concerns 50 years ago prompted the federal government to build the interstate highway system. "The same transportation challenges that the president and Congress faced a half century ago—defense and homeland security, economic productivity, traffic congestion and safety—exist today," said William M. Wilkins, TRIP's executive director.

TRIP's report recommends that Congress index the fuel tax to inflation. It also suggests that interest on money in the Highway Trust Fund accrue to that fund rather than to the general fund, and urges that the trust fund's reserve be drawn down to pay for road improvements.

Meanwhile, a study by the American Association of State Highway and Transportation Officials (AASHTO) found that travel on the interstate system increased by 37 percent from 1991 to 2001, while additional lane mileage increased by just 5 percent. The result is that two out of five urban Interstate miles are now considered congested. In addition, AASHTO's report says, the $65 billion currently spent by federal, state and local government on infrastructure maintenance would have to increase by 42 percent, to $92 billion, in order to maintain roads and bridges and prevent traffic congestion from worsening.