We've heard about the smart roads of tomorrow for years. But now "intelligent highway" technology is inching into the mainstream. One reason is that the number of vehicles on the road is increasing far faster than our ability to add more roads or widen old ones. Consider these statistics from the Federal Highway Administration (FHA). Over the past 20 years, it says, we've built about 2% more streets and roads, but there are more than 50% more vehicles using them-and they travel 77% more miles.

The result is spreading congestion that is affecting broader metropolitan areas. Pending an unlikely swing away from personal vehicles, traffic planners figure the best solution is to manage traffic flow more efficiently.

That's where smart highways come in. A number of possible solutions were demonstrated last year during a big automated highway expo in San Diego. Among them is high-speed "platooning" in which a smart highway takes control of cars and moves them along, bumper-to-bumper, at 70 miles an hour.

Those technologies are years away from implementation. More immediate traffic aids include "smart" traffic signals and roadside displays that give drivers instant updates on traffic conditions ahead.

The potential U.S. market for smart road technology is enormous. A study released two years ago by the U.S. Department of Transportation pegs it at some $430 billion over the 20-year period from 1996 to 2016.

Driving Smarter

There's no question that today's cars are more intelligent than ever. If the technology waiting in the wings is any indication, they'll be even smarter a few years from now. These new features will pamper passengers with new conveniences, protect them more effectively from harm, and minimize the impact of their vehicle on the environment.

No matter how intelligent cars and roads get, however, an old truism about driving remains as valid as ever. It says the most important component in smart cars is the brain behind the wheel.

 Bill Hampton has covered the automobile industry for national publications since 1971.