Innovative Safety Feature Offers Breakthrough in Directional Stability

Mercedes-Benz, the automobile maker that first brought ABS anti-lock brakes to consumers back in 1978, has taken driving safety to a new level with the Electronic Stability Program (ESP). Even the “ESP” abbreviation helps explain the system’s benefit. In essence, ESP works invisibly, seemingly intuitively, to keep the car going exactly where the driver points it, under driving circumstances that might otherwise lead to loss of control and a possible accident without the system. First introduced in model year 1996, ESP expanded throughout the line, and the impressive safety system is standard equipment on all Mercedes-Benz vehicles and calibrated to each specific model.

Winner of the Discover Magazine Award For Technological Innovation in 1996, the breakthrough safety system helps drivers maintain directional stability — especially on slippery or gravel-covered roads — by preventing oversteer (rear-end “fishtailing”) or understeer (front-end “plowing”). ESP can sense impending loss of control — at the front or rear end — and momentarily apply the brake on one wheel to restore stability, something that even a skilled driver cannot do.

Using electronic sensors and computer logic, the new system calculates every microsecond if the car is going exactly in the direction it is being steered. If there’s an appreciable difference between what the driver is “asking” (through the steering wheel) and what the vehicle is doing, the system corrects with split-second speed by applying one of the left or right-side brakes, even before the driver may sense any changes.

ESP uses the angle of the steering wheel and the speed of the four tires to calculate the path being steered, and it gets electronic signals about lateral “g” and vehicle “yaw” to measure what the car is actually doing (Yaw can be demonstrated by rotating a small model car on a toothpick stuck down through its roof; engineers define yaw as the natural tendency for a vehicle to rotate on its vertical centre axis).

ESP measures any tendency toward understeer (when a car is slow to respond to steering changes) or oversteer (when the rear wheels try to swing around, causing the car to “fishtail”). Whenever it senses understeer in a turn, ESP increases brake pressure to the inside rear wheel. With an oversteer tendency, it increases brake pressure to the outside front wheel. Unlike traction control, ESP is effective during acceleration, braking and coasting. The system enhances driver control and helps maintain directional stability in turns as well as when driving straight-ahead, including on uneven surfaces and over patchy snow, ice or gravel.

As a joint project of Mercedes-Benz and Robert Bosch GmbH, the development and testing of the ESP system had been underway for several years before its introduction in model year 1996. Engineers from both companies established a project team labelled “Systemhaus” as part of the Mercedes-Benz “Tandem” project, which fosters close co-operation with suppliers. As a result, the usual time to develop such a system was reduced by one-third, and development costs for the new system were lower than for the basic ASR traction control system. Mercedes engineers used the Daimler-Benz driving simulator in Berlin to evaluate the system under extreme conditions such as strong crosswinds. Separately, they employed a special test centre on the ice of Lake Hornavan near Arjeplog, Sweden.

The Mercedes-Benz ESP system is a technology breakthrough which has been proven to help to reduce car accidents. A study released in 2003 and conducted in Germany shows that ESP reduces single vehicle accidents by 30%. Total vehicle crashes for vehicles equipped with ESP compared to those without the system were reduced by 15%.

About Mercedes-Benz Canada

Mercedes-Benz Canada is responsible for the sales, marketing and service of Mercedes-Benz cars and light trucks in Canada. Headquartered in Toronto, Ontario, Mercedes-Benz Canada employs approximately 830 people in 22 locations across Canada. Through a nationwide network of 17 Mercedes-Benz owned retail operations and 39 authorized dealerships, Mercedes-Benz Canada sold 14,520 vehicles during 2002, representing a 22.2% increase over 2001, setting the highest sales volume in its history.

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JoAnne Caza (416) 847-7550 caza@mercedes-benz.ca
Arden Nerling (416) 847-7556 nerling@mercedes-benz.ca