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OverviewField trials and testing in the simulator: One million test kilometres on the road and two years in the laboratoryOperation and function in detail: How the new PRE-SAFE® brake worksPRE-SAFE® brake: latest Mercedes innovation for safety on the road: S-Class brakes automatically when faced with acute riskPRE-SAFE® brake: world premiere of the first autonomous braking system: Automatic partial braking before impending rear-end
Jun 21, 2006
The new PRE-SAFE® brake from Mercedes-Benz represents a further milestone in car safety. The only system of its kind in the world, it automatically brakes the car before an impending rear-end collision. As a result, the PRE-SAFE® brake, in collaboration with Brake Assist PLUS, is able to prevent the collision or significantly reduce the severity of the accident. This new type of safety technology once again underlines Mercedes-Benz’s leading role in the field of technology. The PRE-SAFE® brake will be available for the S-Class and the new luxury CL-Class Coupé from autumn 2006.
The new system complements Brake Assist PLUS (BAS PLUS), which was introduced last year. BAS PLUS provides visual and audible warnings if it detects that the vehicle is about to run into the vehicle in front and automatically calculates the brake force required in order to prevent the crash. This brake boosting force is available the moment the driver steps on the brake pedal.
The PRE-SAFE® brake goes a step further. If the driver does not react to the BAS PLUS warnings from the cockpit and there is a severe danger of an accident, the system triggers automatic partial braking and decelerates the S-Class at up to 0.4 g (approx. four m/s²). This is equivalent to around 40 percent of the maximum braking performance. Autonomous partial braking provides the driver with a further clear prompt to take action, on top of the visual and audible warnings. If he or she immediately goes on to activate the brake, maximum braking force will be available, and – depending on the given situation – it may be possible to prevent the accident at the last moment. If this is not possible, the PRE-SAFE® brake reduces the severity of the impact, which in turn reduces the risk of injury for the occupants of the car.
The PRE-SAFE® brake is an assistance system, which assists the driver at critical moments. Even during automatic partial braking, the driver retains responsibility for the vehicle and decisive action on his or her part can help prevent the vehicle from colliding with the car in front.
This new technology rounds off Mercedes-Benz’ s unique PRE-SAFE® occupant protection system, which features as standard in the S-Class. The system is based on the principle of prevention and before an impending accident pre-emptively deploys protective measures in the interior, ensuring that the airbags and seat belts are able to operate to optimum effect in the event of a crash. In future many of these pre-emptive measures will be triggered when the PRE-SAFE® brake is activated.
Like Brake Assist PLUS, the new PRE-SAFE® brake uses cutting-edge radar technology to record the situation in front of the car and to recognise the threat of an accident. Behind the S-Class’s front bumper trim are two near-range radar sensors with a range of 30 metres and an effective angle of 80 degrees. The additional long-range radar in the radiator grille has a range of 150 metres.
PRE-SAFE® brake reduces severity of accident by 40 percent
Mercedes-Benz thoroughly tested the function and effectiveness of the new PRE-SAFE® brake both in field trials and in a simulator. Around 500 drivers too part in the field trials in Germany and in the USA, covering a total of around one million kilometres in the test cars.
Mercedes engineers carried out a series of tests over a period of several weeks using DaimlerChrysler Research’ s simulator in Berlin. 70 drivers took part in these tests, which lasted half an hour. The scenario each time involved the participants being deliberately distracted by an accident on the opposite carriageway while the queue of traffic in front suddenly braked at the same instant. The results of the test, which reflects an everyday situation on the road, document the safety benefits offered by the S-Class’s cutting-edge assistance systems: thanks to the rapid reactions of the drivers, and support from BAS PLUS and the PRE-SAFE® brake, a total of 70 percent of these test drives remained accident-free. The tests therefore show that the likelihood of an accident can be significantly reduced by the S-Class systems.
In one third of the simulator tests the participants were unable to prevent a collision. Here automatic partial braking succeeded in reducing the severity of the accident by around 40 percent.
Just as with the airbag, belt tensioners, ESP® and other groundbreaking Mercedes inventions, there was a clear focus on real accident data during development of the PRE-SAFE® brake. In interaction with Brake Assist PLUS, the new technology is able to make an important contribution towards lowering the high number of rear-end collisions or reducing the severity of this kind of collision. In Germany over 17 percent of all serious traffic accidents fall into the category of rear-end collisions. In the USA every third accident involving fatalities and injuries is a rear-end collision.
Mercedes-Benz will be offering the PRE-SAFE® brake as an option for the S-Class and the new CL-Class Coupé in conjunction with DISTRONIC PLUS proximity control and Brake Assist PLUS from autumn 2006.