High-Tech Vehicle Safety Systems Brake Assist

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Brake Assist In emergency stop situations, some drivers fail to brake hard enough, or soon enough, and are consequently involved in more serious collisions than might otherwise be the case. Brake assist systems apply the brakes fully in order to prevent a crash or at least to reduce the collision severity.   How do they work? Modern vehicles are equipped with power-assisted braking systems. These feature a brake booster system that typically uses either engine vacuum or an electric motor to reduce the force that the driver needs to apply on the brake pedal to generate the desired level of vehicle braking. In vehicles also equipped with brake assist, a sensing system identifies when the driver is pushing on the brake pedal hard and rapidly, with the intention of making an emergency stop. A control system then activates the brake booster system to maximize the braking effort early in the event. Brake assist provides for a greater degree of braking than in the case of tentative driver action. The system can result in a collision being completely avoided or, at least, it will minimize the severity of a collision that does occur by reducing the vehicle's speed as much as possible. Some systems use an adaptive learning technique where the sensing and control system monitors the driver's braking pattern and identifies the characteristics of non-emergency and emergency braking actions.   What can science tell us? The New Brake Assist of Mercedes Benz-Active Driver Support in Emergency Braking Situations; Walter Klinkner, Wolfgang Kiesewetter, Werner Reichelt and Manfred Steiner; SAE Paper No. 977140; October 1997 The development of Brake Assist is based on the results of Daimler-Benz Research which reveals that in critical situations, car drivers tend to put their foot down fast enough, but not firmly enough, on the brake pedal. In the initial stages of braking, the electronic Brake-Assist system automatically builds up maximum braking pressure within a fraction of a second, thereby considerably reducing the car's stopping distance. Are Expected and Observed Effectiveness of Emergency Brake Assist in Preventing Road Injury Accidents Consistent?; Yves Page, Jean-Yves Foret-Bruno and Sophie Cuny; Proc. 19th ESV Conf.; Paper No. 05-0268; June, 2005 (235 KB PDF) This paper estimates the expected and the observed effectiveness of Emergency Brake Assist (EBA) systems in terms of reduction in injury accidents in France. The effectiveness estimates were for a 7.5% reduction of car occupants fatalities, a 10% drop in pedestrian fatalities, and an 11% reduction in overall injuries.   Useful links Brake Assist Systems (Continental Automotive) EC pushes need for Brake Assist Systems in new cars   On-line Video Clips Brake Assist Systems Animation (4.27MB Quick Time Movie)

Quick Facts The vast majority of drivers react to emergency situations by braking Most drivers don't apply full braking early enough Brake assist boosts the braking action in an emergency This can prevent a crash or reduce collision severity   Associated systems: Anti-Lock Brake Systems Traction Control Systems Electronic Stability Control