A few months ago in Michigan, a sedan, followed by a minivan – both rigged out with prototype wireless communications equipment and software – swung onto Halsted Road in Farmington Hills. The driver of the sedan then slammed on his brakes, as if a dog had run in front of his bumper. This is the kind of abrupt move that can cause a rear-end crash, especially when visibility is poor.

But this particular sedan had a computer in its trunk outfitted with a Global Positioning System receiver and a short-range radio. The abrupt brake-jamming registered on the computer, which broadcast a warning and the sedan’s GPS location. The minivan, similarly equipped, picked up the warning via special radio frequency, calculated that the sedan’s location was just ahead of its own, and warned the driver, sounding a chime and flashing a red light.

The vehicles were testing Motorola communications technology as part of a corporate and government push to blanket roads with wirelessly broadcast safety information over the next decade, saving lives by getting cars’ computers to talk to each other. To be sure, communications-driven auto safety features have been envisioned for years. But Motorola’s tests are part of a new wave of projects that are using such technology in actual vehicles, on public roads, for the first time. “There are possibilities for information exchange that hitherto were only imagined,” says James Misener, program leader in transportation safety research at the University of California, Berkeley.

[For an illustration of a wireless highway safety test click here.]

One reason for that explosion of possibilities is that late-model cars are already loaded with sensors. Computers in today’s cars track dozens of driving parameters, like when antilock braking systems are activated, the rate of deceleration, and when temperatures near the road surface near freezing. This kind of data could help other cars avoid hazards – and each other – if shared in the right ways.

For example, in Southfield, MI, the state Department of Transportation has outfitted light poles at intersections with transponders made by Azulstar, the wireless-networking firm. These gadgets can broadcast a traffic light’s GPS position and its state: red, yellow, or green. Approaching cars equipped with prototype computers can examine this data, together with information on speed and location, and alert drivers who seem likely to run red lights.

And as part of the Motorola project, transponders housed in small gray boxes have been affixed to light poles along several kilometers of local streets in Farmington Hills. The roadside radio units have a range of 1.6 kilometers. Vehicles could collaborate with transponders to relay data across long distances to give drivers farther afield advance notice about conditions ranging from bad weather to dangerous road conditions to accidents.

While 10 states plan to participate in similar tests, Michigan says its roads will soon have the largest number of specially equipped vehicles and roadside transponders. Later this year, Chrysler will outfit a batch of cars with autonomous communication systems and test them itself in Auburn Hills and Southfield.

This rash of testing represents a changing approach to auto safety. Despite years of incremental efforts to make vehicles safer – air bags, antilock brakes, pretensioning seatbelts – the number of annual U.S. traffic fatalities has remained above 40,000 for a decade, partly because the total numbers of vehicles on roadways continues to increase. “We’ve kind of reached the end of the road with passive safety,” says Steve Speth, director of the Vehicle Safety Office at the Chrysler Group.

Now the emphasis is on using wireless technology to help drivers actively avoid accidents – especially at intersections, the site of 17 percent of vehicle fatalities. “Once we start connecting vehicles, we will see a reduction in the total number of fatalities,” says Peter Sweatman, director of the University of Michigan Transportation Research Institute in Ann Arbor. “That really is the future direction of auto safety.”

The Federal Communications Commission has set aside a swath of radio bandwidth strictly for short-range communications on the nation’s roads. It’s an essential provision: cellular telephone networks do not establish connections fast enough.

Wireless auto safety still faces roadblocks, like questions about carmakers’ liability if, say, the technology doesn’t prevent a crash. But Ford, General Motors, DaimlerChrysler, and Nissan have linked up with the Michigan DOT to perform experiments like Motorola’s. And they’re joining with Toyota, BMW, and Volkswagen for collision avoidance tests on public roads. Some applications could be in cars soon; Ford, for example, plans to start tests in 2007 for possible production by 2011.

Home page image courtesy of Funnelinc.com.