For 2011 U.S. models, PRE-SAFE Brake, in combination with DISTRONIC PLUS, can now apply full-power braking automatically in emergencies to reduce the severity of an accident. Available in the 2011 E-Class line as well as the CL coupe and S-Class sedan, the PRE-SAFE Brake system sounds three warning tones when it senses an impending collision.

About 1.6 seconds before impact is likely, partial braking is automatically initiated, and the PRE-SAFE occupant protection system is activated. If the driver still fails to react, full-power braking is initiated about 0.6 seconds before the collision, reducing the impact and acting as an “electronic crumple zone.”

The initial development of PRE-SAFE was based on the findings of Mercedes-Benz engineers investigating real world accidents, who concluded that about two-thirds of all accidents are preceded by distinct, precarious driving events such as skidding, emergency braking or a sudden evasive maneuver – all of which can provide valuable seconds of advance warning before impact. Until recently, the auto industry was not able to make use of this relatively wide and potentially lifesaving “window.” Conventional air bags and seat belt tensioners are triggered only when the impact actually occurs.

PRE-SAFE Gives Cars Reflexes to Protect Occupants
PRE-SAFE is a revolutionary safety system that can actually sense an impending collision before it happens and take measures to protect occupants during those valuable seconds before impact. Standard equipment on three Mercedes-Benz sport utilities – the M-, R- and GL-Class – as well as the S-Class sedan, CLS and CL coupe and E-Class model lines, the PRE-SAFE system automatically tightens the front seat belts before a possible impact, and the front passenger seat (and any optional power rear seats) moves to a position that can provide better protection. If the system senses an impending rollover, the sunroof also closes.

The latest version on the S-Class sedan, CL coupe and 2011 E-Class model lines also closes the side windows to provide better support for the window curtain air bags, and can inflate special seat cushions that provide more lateral support for occupants and help the side impact air bags provide even greater protection if and when they deploy.

Vehicles equipped with the radar-based Distronic Plus can identify if the car is gaining too quickly on vehicles driving ahead of it. If the system determines the closing speed is too high, Distronic Plus can help to ready Brake Assist and, in turn, trigger PRE-SAFE measures.

Anticipatory Safety Systems
Mercedes-Benz initiated the idea of anticipatory measures years ago. In model year 1990, the SL roadster was first equipped with an automatic roll bar that pops into position in a third of a second if the car senses an impending rollover. While the current SL is equipped with such an active system, the SLK features two fixed roll bars.

Source: Daimler AG