Gridlock is getting worse because U.S. urban areas haven't added the road capacity needed to keep up with growing populations, according to a new study.

The Texas Transportation Institute reports that congestion delayed drivers 79 million more hours and wasted 69 million more gallons of fuel in 2003 than in 2002, the latest years studied.

But there's good news, too. According to study co-author David Shrank, it doesn't take a multi-million-dollar highway program or a new subway system to relieve congestion, although all of that helps. Smaller steps -- such as ramp metering and coordinating traffic signals -- also make a difference, cumulatively reducing delays by about 8 percent in the 85 urban areas tracked by the study.

In seven major cities U.S. cities -- Dallas, Los Angeles, San Francisco, Miami, New York, Houston and Philadelphia -- the annual delay per rush-hour traveler actually went down slightly. But researchers say this doesn't necessarily mean traffic in these areas improved; it may simply reflect delays that have spread to the suburbs.

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