Brake Assist (BA or BAS) is a generic term for an automobile braking technology that increases braking pressure in an emergency situation.
The first application was developed jointly by Daimler-Benz and TRW/Lucas-Verity. Research conducted in 1992 at the Mercedes-Benz driving simulator in Berlin revealed that more than 90% percent of drivers fail to brake with enough force in emergency situations. Brake Assist detects circumstances in which emergency braking is required by measuring the speed with which the brake pedal is depressed. When panic braking is detected, the Brake Assist system automatically develops maximum brake boost in order to mitigate a drivers tendency to brake without enough force. In doing so, Brake Assist has been shown to reduce stopping distance by a signifcant margin; up to 20% in some studies. In December 1996 BAS premiered to the world on the Mercedes-Benz S-Class and SL-Class. In 1998 Mercedes-Benz became the first company to make Brake Assist standard equipment on all its models; other brands including Volvo and BMW soon followed suit.
The Mercedes-Benz Brake Assist Plus (BAS Plus) is the latest generation of this technology and was first made standard equipment on the Mercedes-Benz S-Class. This system uses radar to calculate the proximity to other vehicles; and if the gap gets small or the closing speed is too high the system will warn you on the dashboard. If an impending collision is likely the system will calculate the optimal braking power to avoid the accident in a fraction of a second, and as soon as the brake pedal is applied by the driver, even lightly, the optimal braking is immediately applied thus avoiding the otherwise probable accident. The BAS Plus system has been shown to significantly reduce the incidence of rear-end collisions, and so is very significant in the development of driver aids that improve road safety.
The BAS Plus system can also be used in conjunction with other driver aids (Distronic Plus) which allow the car to be automatically brought to a halt in stop and start traffic or temporarily slowed down during motorway cruising.