Car tech: Taking drivers' helpers for a spin

Computerworld - You're driving down the road, and suddenly another car swerves behind you and approaches in your blind spot just as you were preparing to change lanes. Your car gives you a quick nudge on the steering wheel and a soft tap on the brakes, and you're back in your lane -- safe and sound.

Every car maker has at least one vehicle in its line-up equipped with technology-related aids such as automatic parking or adaptive cruise control. In car-industry parlance, these helpers are known as Advanced Driver Assistance Systems (ADAS). The Cadillac STS, the Buick Lucerne, the Mercedes E-350, the Ford Fusion, the Mazda3 and the Infiniti M are all equipped with features that aim to help drive a car better than a human could alone, or least make split-second decisions better.

The TV commercials spell out the basics: an Audi A8 has lights that swivel around a dark corner in the road, and an Infiniti brakes automatically to prevent a collision. But you might wonder how these features actually work. What is the technical wizardry? To find out, I test-drove several of the models and asked the experts at each company for the nitty-gritty details.

Lane-departure warning

This feature debuted with the Infiniti M in 2001, and it has proven to be a major hit even in relatively less expensive vehicles such as the Buick Lucerne. During a test drive, the Lucerne displayed a subtle green icon in the dashboard showing proper lane alignment, but glowed amber when the vehicle veered off track.

According to John Capp, the global safety director at General Motors, both the Lucerne and several Cadillac models (such as the STS with a premium package) use a black-and-white camera mounted near the rear-view mirror to constantly scan the road using a pattern-recognition system. The camera looks for tonal intensity -- interpreting the difference between a bright white or yellow line, for instance, versus a dull gray curb.

Lane assistance warns you when the car veers out of a lane on the highway. Here, a diagram shows how the camera spots white lines on the road and measures vehicle placement.

Capp says GM is evolving the camera to do more and more. In Europe, the Opel Insignia scans road signs to find the current speed and alerts you if you are going too fast, which can be an issue in countries like Germany where the driver might not notice the infrequent speed-limit signs. To make it work, GM programmed the Lucerne's LDW (lane departure warning) camera for the Opel Insignia to read speed-limit signs.

On Lexus vehicles, lane warnings also use forward-scanning radar to look ahead of your car for other vehicles and identify lane markings and even a dark shoulder (or berm) to warn you about wandering out of your lane, according to Paul Williamson, a Lexus manager who helps train dealers in advanced technology. Models such as the Lexus HS250h can even nudge you back into the lane automatically.