Are driverless cars next?

The New Jersey Turnpike. The Capital Beltway. The San Diego Freeway. The George Washington Bridge. Atlanta’s Downtown Connector. The Dallas “Mixmaster.” These roads, some of the most congested in the country, inspire dread and loathing in all but the most stalwart of travelers. They thwart the lane-changers, tailgaters and speeders.

Economists, Nobel Prize-winning physicists and traffic psychologists all have sought solutions to the nation’s congestion problem, as have urban planners and civil engineers. However, current plans to expand roads and introduce specialized tolls do not address the ultimate cause of traffic: people.

The best way to eliminate congestion, some experts say, is to take the driver out of the driver’s seat.

“We wouldn’t have to deal with people behind the wheel,” says Jerry Schneider, a University of Washington professor emeritus of urban planning and civil engineering. “It would be a totally hands-off, brain-off experience.”

Driverless design concepts include Personal Rapid Transit, which involves passenger taxi-pods on rails; automatic highway systems that direct driverless cars using magnetic guidelines; and dual-mode systems with cars that can be driven normally on smaller roads and for shorter distances but could go driverless on specialized electric rails, or “guideways,” for high-speed controlled travel.

“In the morning, you would drop the kids off at school, drive to the guideway, sit back, read the paper and automatically get off where you want to go,” says Kirston Henderson, president and inventor of MegaRail Transportation Systems, a dual-mode company based in Texas.

Mr. Henderson, a former designer of military aircraft systems, has developed several dual-mode concepts with 12 other retired engineers. “Many years ago, I saw coming massive congestion and steadily rising prices of oil and set out to find a better way,” he says. “Our system solves a tremendous problem in cost, air pollution and traffic.”

Indeed, increased efficiency from higher speeds, standardized spacing between cars and driverless driving could dramatically increase road capacities. A normal highway lane can carry about 2,000 cars an hour, Mr. Schneider says, but a dual-mode “lane” could handle 15,000 or more.

Traffic congestion is a “$78 billion annual drain on the U.S. economy in the form of 4.2 billion lost hours and 2.9 billion gallons of wasted fuel,” the Texas Transportation Institute said in its 2007 Urban Mobility Report, with the average rush-hour commuter losing $710 a year while stuck in traffic.

The billions of gallons of gas wasted while idling on the highway produce 27 billion kilograms of greenhouse gases out of the 7 trillion kilograms emitted yearly in the United States.

Traffic physicists (including the late 1977 Nobel laureate Ilya Prigogine) have looked at traffic flow from the perspective of fluid dynamics, describing cars interacting on the road like liquid moving through a pipe.

Traditional approaches to reducing congestion focus on “making the pipe bigger” by expanding roads, which is only a temporary remedy, says Anthony Downs, an economist at the Brookings Institution.

Mr. Downs believes in reducing the amount of fluid in the pipe by making it more expensive to use roads at peak times or in crowded areas. For example, special high-occupancy toll lanes would allow drivers to pay more for a faster trip, and congestion pricing (as in a recently defeated plan proposed for downtown Manhattan) would charge higher tolls for drivers to enter a congested area, encouraging them to switch to public transportation.

However, solutions that focus on the physical aspects of traffic may be overlooking the real problem.

“Congestion is often not caused by the road, but by the way drivers are driving,” says Leon James, a psychology professor at the University of Hawaii and a pioneer in the small field of traffic psychology. When one driver in traffic makes a mistake, tailgates or changes lanes unnecessarily, hundreds of drivers may suddenly have to put on the brakes.

“We call it a traffic wave,” he says. “Everything suddenly slows to a crawl, but there’s no obstruction.”

That, in turn, has a psychological effect. “Congestion makes you feel frustrated and panicky,” says Mr. James, who recommends a program of lifelong driver education to help deal with the cognitive problems caused by driving.

“Many people are driving around in a constant seething rage,” he says.

However, dual-mode concepts could take the rage off the road. The Texas Department of Transportation recently funded a study by the Center for Energy, Environment and Transportation Innovation at Texas A&M University that reviewed 102 dual-mode concepts (including MegaRail’s). The study, which will be released shortly, concluded that dual-mode, though in its early stages, is very promising, says Jim Longbottom, one of the founders of the center.

“The technology has the potential to solve a lot of traffic and pollution problems,” he says. “There would be energy gains, security gains, safety gains, capacity gains.”