by Jim Kerr

Cadillac is proving to be both the image and product leader in General Motors’ line-up of vehicles. The sharp, angular lines of the new Cadillac models are the most obvious changes over the past few years.

2005 Cadillac STS. Click image to enlarge

But beneath that exterior, they have also been busy developing new powertrains, suspensions and electronic features. The new 2005 Cadillac STS’s cruise control system is one of many interesting new developments.

Cadillac calls it Distance Sensing Cruise Control, or DSCC. This option uses a 76-gigahertz radar system to monitor both the road and traffic to control the Cadillac’s speed. Developed by Continental Temic, part of the same company that produces Teves ABS brake systems, the cruise control does much more than just maintain vehicle speed.

The key components of the DSCC include a radar sensor and module located behind the grille, a Head-Up Display, and driver’s information centre to provide feedback information to the driver and cruise control switches on the signal light stalk and steering wheel. During operation, the system operates just like any other cruise control – set the speed and the car will stay there. The difference with this system is when traffic or road conditions change.

If the DSCC senses that there is another vehicle ahead, it switches to “follow” mode. The DSCC module slows the car to match the speed of the vehicle in front. The distance between the two vehicles can be set by the driver by pressing + or – on the “Gap” switch on the steering wheel. Pressing the + side will increase the distance upward from one second to a maximum of two seconds’ following distance — a safe distance to allow for braking when travelling at 100 km/hr. If the vehicle in front changes lanes or turns, the DSCC will automatically accelerate the Cadillac back to the cruise control’s set speed.

The DSCC module can detect more than cars. The design parameters are such that it must be able to sense a one-square-metre vehicle in a 3.6-metre-wide wide lane at 100 metres, or about the size of a small motorcycle. (I wonder if it would detect deer as well.)

The DSCC also senses the shoulders of the road. If the roadway in front of the vehicle curves, the DSCC module detects the sharpness of the corner and displays a “tight curve” message to the driver, while simultaneously slowing the vehicle for the corner.

Collision warnings are also built into the system. If the gap between the two vehicles is decreasing rapidly, such as when the front driver brakes, the DSCC module will flash a red warning icon to the driver, chime a warning on the radio speaker, and brake the car automatically at a maximum rate of .3Gs, while turning on the brake lights to warn following drivers. Decelerating at .3Gs is not that fast, but it definitely wakes the driver up and decreases reaction time, so the driver is able to brake or steer to avoid the vehicle in front.

However, the system may not be able to detect a stopped vehicle quickly enough to warn the driver and allow enough reaction time. The driver must still stay alert to traffic conditions.

Snow and dirt can affect the radar signal, so drivers may get a message that DSCC is not available if they have been driving in inclement weather. Wash off the Cadillac grill emblem in front of the DSCC module and you are ready to cruise again.

There are many vehicles now on the market with optional cruise control systems that use radar or sonar sensing, including Jaguar, Lexus, Mercedes-Benz and Toyota. The Cadillac system is similar in operation to others but represents the latest in cruise control technology.