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 better protection if an accident should occur. PRE-SAFE® system (optional in R 280) works together with 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 are tensioned instantly, the front passenger seat is adjusted to a more favourable position, and if a certain lateral acceleration threshold is exceeded the sunroof is closed. Once the danger has passed, the belt tensioning is released. All the other systems can then be returned to the desired positions manually.