A new U.S. General Accounting Office report on the current state of the Interstate Highway System found that the overall physical condition of the system has improved over the last decade, but that growing capacity needs are not being met.

The report was requested by U.S. Rep. Don Young (R-Alaska), the Chairman of the Transportation and Infrastructure Committee
As of 2000, the Interstate Highway System extended over 46,000 miles in length and comprised 209,655 lane miles. From 1954 to 2001, the federal government invested over $370 billion on Interstates through apportionments to the states. Most state officials today see the Interstate as increasingly supporting economic growth and moving freight, as well as getting passengers to airports and supporting urban travel.
While the report notes significant improvements to the structural quality of Interstate highways and bridges, it also indicates that the relatively small capacity increases in the highway system have not nearly matched the demands placed on the system by the much larger increases in traffic. As a result, congestion and other costs related to capacity shortages continue to grow.
"Despite the strides we have made in improving highway structures and surfaces, the report makes it clear that we need to be doing more to handle the performance of the Interstate System," said U.S. Rep. Tom Petri (R-WI), the Chairman of the Highways and Transit Subcommittee. "I am particularly concerned with the effect of congestion on timely delivery of freight, which is expected to nearly double between now and 2020,” Petri said. “Clearly, Congress must find ways to relieve the congestion problem on the Interstates as expeditiously as possible."
According to those surveyed by GAO, the most important role that the Interstates perform, other than supporting safe travel, is moving freight traffic across the states. Truck travel on the Interstates accounted for over 41 percent of total truck miles traveled in 2000. Trucks carry over 69 percent of the tons shipped in the states and 72 percent of the value of goods shipped in the country. From 1990 to 2000, Interstate lane miles increased 6 percent while freight by intercity truck ton-miles increased 40 percent. In addition, a 2001 study estimates an annual 6.9 percent increase in Latin American truck traffic in the United States (resulting in almost a doubling in 10 years), most of it on the Interstates.