Keeping Cars From Crashing

Members are developing warning systems to save lives

8 September 2010
tech A Delphi collision-warning system relies on radar and vision sensors to detect potentially hazardous situations at the front, sides, and rear of vehicles. The system then warns drivers. Image: Delphi

It's no secret that motor vehicle accidents are one of the leading causes of death. Less well known is that more than 90 percent of fatal vehicular accidents involve driver error. Drivers tailgate, fall asleep at the wheel, suddenly change lanes, and back into things and people. Several IEEE members are working with a new breed of driver-assistance systems to keep accidents from happening.

The new systems can, for example, keep cars a safe distance apart, spot objects—or pedestrians—lurking in a driver's blind spot, and warn drivers when their cars are drifting into another lane or about to hit something. Ideally, the systems will prevent accidents from happening. If not, they might at least reduce the damage that results from a collision.

"Our goal is to provide the most advanced technologies to assist the driver while maintaining hands on the wheel and eyes on the road," says IEEE Member Steve Buckley, senior technical specialist of active safety systems with the Chrysler Group in Auburn Hills, Mich.

"Potentially, these systems could save thousands of lives," says Member Michael Thoeny, global director of engineering for Delphi's Electronic Controls Product business unit. The Troy, Mich., company is a leading supplier of electronics to automotive and commercial-vehicle manufacturers. Its active safety customers include Ford, Land Rover, and Volvo.

Advanced driver-assistance technologies include adaptive cruise control, imminent braking systems, forward-collision warning, blind-spot monitoring, and lane-departure warning. They have been available as options in luxury models from Audi, BMW, General Motors, Volvo, and other manufacturers and are found in commercial vehicles. But they are also beginning to appear in midpriced cars from Chrysler, Ford, GM, Honda, Toyota, and others.

What's more, buyers of new automobiles may soon find these options included as standard equipment. Increasingly, countries see such features as a way to make their roads safer. The European Union, for example, has insisted that some of the new safety systems be included as standard equipment. Lane-departure warning and imminent braking systems will be required on certain heavy-duty vehicles starting in 2013, with consideration for passenger cars not far behind, according to Thoeny.

The United States does not yet require any of the technologies to be standard, but the U.S. Department of Transportation's National Highway Traffic Safety Administration is adding forward-collision and lane-departure warnings to its 2011 New Car Assessment Program, a rating system that evaluates vehicular crashworthiness and rollover safety. Car manufacturers—including ones in Australia, China, Japan, and Europe—use these ratings to market their vehicles.

SENSORS GALORE
In all the new systems, sensors play a major role, with radar, vision sensors, and lasers monitoring a vehicle's immediate surroundings to create "a cocoon of safety around the car," Thoeny says.

Adaptive cruise control uses forward-looking radar to track vehicles and objects, Buckley says, and to detect vehicles moving in front and measure their distance and relative speed. The system also relies on a number of other sensors. In addition to the radar sensor, the system processes data from speed, yaw rate, and steering-angle sensors. It also uses a digital signal processor and longitudinal controller. By adjusting engine speed and applying the brakes automatically, the system ensures that a preset distance is maintained between vehicles in the same lane.

Delphi's forward-collision warning system employs visual or audible alerts to notify drivers if it senses a potential collision. It uses a camera, a vision processor module, and a radar sensor. If the driver fails to react to the warning, the system automatically applies the brakes.

Radar also plays a role in blind-spot monitoring. Chrysler's version mounts shorter-range radar sensors on the side of the vehicle to detect other vehicles that might be lurking in the blind spot. A small triangular warning light in each side-view mirror lets the driver know if something is there. Radar sensors can also detect vehicles crossing behind you when you're backing out of a parking spot.

Lane-departure warning systems use a video camera and image-processing techniques that look at lane markings and edges ahead of the car to detect objects and vehicles. If the car crosses a lane divider without a turn signal being turned on, the system uses audible and visual warnings and a vibration in the steering wheel to alert the driver.

TOO MUCH HELP?
The technology provides drivers with more protection, but does it also reduce the control they have over their cars? Motorists can override some of the systems being developed by Chrysler and Delphi, including adaptive cruise control and lane-departure and forward-collision warnings.

Chrysler lets the driver select the following distance, or permits the forward-collision warning system to be turned off entirely. But other features, such as collision mitigation by braking, are part of the vehicle's core safety system and can't be disabled, Thoeny says.

"There will always be real-world situations that can be addressed only by the driver," he says. "Our intent is to keep the driver in the loop as much as possible and only take over control of the car when collisions are imminent

"These systems are trying to recognize situations where drivers are not responding and to provide an alert that is going to pull their attention back to where it needs to be: on the road," he continues. "Driver-related problems like distractions, fatigue, and alcohol impairment scream out for more than passive safety systems."

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