The next time you're sitting in traffic, consider the question of how much traffic congestion could be costing the U.S. economy. It's a topic of vital interest to shippers in an age when customers rarely tolerate shipment delays.

According to the 19th annual Urban Mobility Report, researched and published by the Texas Transportation Institute, American communities of all sizes are facing more and longer traffic delays, and they are mighty costly.

According to the study's authors, roadway congestion now costs $67.5 billion per year. That represents 3.6 billion hours of delays and 5.7 billion gallons of excess fuel caused by those delays in the 75 urban areas that were studied.

In her recent testimony before the House Transportation and Infrastructure's Subcommittee on Highways and Transit, Federal Highway Administrator Mary E. Peters said that increased traffic congestion was a threat to the U.S. economy as well as to the nation's quality of life. Peters was testifying at a hearing on increasing capacity and improving highway efficiency.

Roadway congestion must be addressed with a long-term strategy that will increase capacity, make the system more efficient and preserve the nation's system of roads and bridges, Peters said at the hearing. "Unless we manage highway congestion, our nation will continue to incur economic costs in forgone productivity, wasted fuel and a reduced quality of life," she said. "Congestion and bottlenecks ... waste significant time and money, and they reduce productivity."

She told the committee that from 1980 to 2000, the number of drivers increased by 30 percent. During that same period, the number of highway miles traveled increased by 80 percent, even though the number of highway miles in the system increased by only 2 percent.

At the moment, 84 percent of the nation's $7 trillion worth of freight traffic travels on highways, and truck travel is expected to grow by more than 3 percent annually over the next 20 years.

To enhance the operation of highways, Peters called for increased coordination among organizations that are responsible for roadway operations, including traffic, public safety, parking, media and emergency response agencies.