Congestion on the nation's highways has gotten so bad that the average person spends 36 hours a year sitting in traffic, a new report says.

Two years earlier, the national average was 34 hours. In 1982, that same person spent 11 hours in traffic annually.

The findings were released Monday by the Texas Transportation Institute, part of Texas A&M University, which studied congestion in 68 urban areas. The data was compiled by 11 state highway departments.

Congestion costs an estimated $78 billion a year in wasted time and burned gasoline, the institute said.

The most congested highways in the country were found in Los Angeles, where residents in 1999 averaged 56 hours a year -- more than a work week's worth of time -- in bumper-to-bumper traffic.

Study co-author Tim Lomax, a research engineer, said new highways, buses and trains are not keeping up with new housing and new businesses.

"It's a whole lot easier to start a manufacturing company or a software firm or build new housing than it is to put in a new highway or new street or even a new bus route or ridesharing program," Lomax said. "Virtually all of the things we're trying to do to improve the mobility are not growing as fast as the cause of the problem."

A research group funded by the construction industry warned that growing congestion could hurt the economy.

"Increasing traffic congestion nationwide threatens to put the brakes on the nation's economic growth," said William Wilkins, executive director of The Road Information Program. "The high quality of life that Americans enjoy today is jeopardized because our highway system is inadequate to meet the growing need for the reliable movement of goods."

While most residents of the Los Angeles area have little choice but to drive to work, people living in some other congested areas can leave the driving to someone else, according to an advocacy group that favors alternatives to highway construction.

The Surface Transportation Policy Project, a coalition of public interest and professional organizations, says that while San Francisco, Washington and Chicago may be three of the five most congested areas, residents there also can avoid the highways by taking mass transit. Residents of other cities, like Las Vegas and Detroit, have no choice but to sit in traffic.

"The burden imposed on the Washington region by congestion is actually much lower than a lot of other cities, even though our rush hour is pretty bad," said Roy Kienitz, the group's executive director. "If you live in Detroit, you tolerate it, you sit in your car and steam comes out of your ears. If you live in Washington, you have lots of choices."