If you happen to brake abruptly, the R-Class is already primed to respond due to its highly sensitive sensors. The advantage is that you have earlier and even better protection if an accident should occur. PRE-SAFE® uses information from a number of systems, including the sensors of the Electronic Stability Program (ESP®) and Brake Assist (BAS). If these identify a critical situation, the driver and front passenger seat belts can be tensioned instantly and the front passenger seat can be adjusted to a more favourable position (only in conjunction with the optional memory package). If a certain lateral acceleration threshold is exceeded the sunroof and the side windows can also be closed. Once the danger has passed, the belt tensioning is released. All the other systems can then be returned to the desired positions.