Wireless: The new backseat driver?

The family sedan might soon be able to talk to the SUV in the next lane. GM is getting the tech in gear. Photos: Crash-free Caddies

SAN FRANCISCO--Just in case you don't have enough backseat drivers, your car could one day tell you when you're about to screw up.

On Thursday, General Motors demonstrated a vehicle-to-vehicle, or V2V, wireless communication system that alerts you when a collision is imminent. The automaker equipped regular Cadillac STS sedans with wireless and Global Positioning System antennae and computer chips that allow the cars to communicate with other vehicles with similar equipment.

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The technology, demonstrated here with three cars navigating a special course, creates what could be described as a digital-driving symphony. The wireless technology in one car detects the presence of the other two Cadillacs and avoids collisions by either alerting the driver of danger or by automatically stopping the vehicle in an emergency.

In terms of an alert, the driver's seat gives off a heavy vibration to the left leg if the driver signals to enter the left lane, unaware of a car in his or her blind spot. Such a warning is an example of what, in the auto industry, is called "haptic feedback"--feedback related to the sense of touch. There's a visual cue too: An icon flashes in the car's rearview mirror to alert the driver that there's another car in the way.

"We're trying to standardize the wireless communication between cars, and we hope other car manufacturers will follow. This would be the reinvention of the vehicle," said Priyantha Mudalige, senior research engineer at GM and one of the four engineers who built the wireless safety system.

Of course, that's the obvious downside to this intriguing technology: For it to work effectively, all vehicles on the road would have to be fitted with similar equipment. Theoretically, if just one car on a busy highway lacked the right gear, the consequences could be severe.

"Before this works, we need to have market penetration," Mudalige said.

GM expects it could be five to 10 years before the safety system could go into production, Mudalige said. That's because it will likely take that long to sign agreements with other manufacturers and with standards agencies like the Federal Communications Commission.

Here's how the technology works:

A GPS antenna on the top of the car receives satellite information on the positions of other cars. A wireless antenna on top of the vehicle also receives up to 100 different data points from the car's internal network, including information on speed, braking and the use of turn signals. The computer system combines that data and broadcasts it.

That message is heard by any other equipped car within a quarter-mile radius. To ensure privacy, the messages do not include car identification numbers or personal information.

The car's software constantly calculates, in real time, other vehicles' positions and speeds. GM's proprietary algorithm, called the "threat assessment algorithm," also processes data from the GPS and the car's computer network, along with messages from other cars, in order to fire off warnings and prevent collisions.

The car's dashboard computer screen will also show icons of nearby vehicles. The typical green icon will turn yellow if there's reason for caution (the distance between vehicles is decreasing at a fast clip, for instance). The icon will change to red if there's imminent danger, and at that time, the driver's seat will vibrate.

Drivers can turn on an automatic braking feature to ensure the car will stop in the event of an upcoming crash.

GM is using the communication protocol called Dedicated Short Range Communication, or DSRC, to send and receive messages. The cars communicate using the wireless spectrum 5.9 gigahertz licensed from the FCC for public safety. Toll agencies already use the spectrum to automatically charge commuters with digital IDs.

The Cadillac prototype itself has four computers in the trunk, along with a GPS system and wireless communication module. GM would try to fit much of the software onto a single chip by the time the cars would be ready for production.

The technology was researched over the last two years, but serious development began a year ago by four engineers in GM's internal research and development department, said Mudalige.

One of the biggest benefits of the wireless system would involve cutting the costs of radar and so-called lidar sensors, which measure speed and distance. GM, BMW and many other carmakers currently use those sensors in luxury cars for features like adaptive cruise control, which modulates the speed of a car based on surrounding vehicles.

Mudalige said the wireless sensors could do the work of the long-range and short-range sensor technology much more inexpensively because they're relying on wireless communication between vehicles. To get the same surrounding effect of wireless V2V sensors, carmakers would have to put radar sensors in many places on the car, which would be too expensive. The wireless sensors cost about $100, he said.

Cars like BMW's Mini Cooper already include sensing technology that alerts the driver when the car is too close to another vehicle while parallel parking, for example. Those sensors are lidar and radar sensors. To get the same effect with wireless technology, GM and others would have to build infrastructure in parking lots, for instance.

The V2V system is still far from perfect in other ways, too. In a test drive with a reporter as passenger, the car's computer system failed during an emergency stop. Luckily, Mudalige took over by braking himself.

Despite such bugs, Mudalige is still confident about cars communicating wirelessly. The technology could not only help protect people, it could also help traffic advisers detect and deliver alternate routes to commuters during traffic jams.

"The auto industry will definitely go towards wireless because it's a significant benefit to society to save lives, reduce pollution and for energy conservation," he said. "This is just the beginning."

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