AS well as dual front airbags, the CLK has side airbags, seatbelt pretensioners and belt force limiters. If the front passenger seat is unoccupied, the side airbag, front airbag and seatbelt pretensioners are disabled, saving repair costs in the event of a collision. Once the car has reached 8km/h the doors, fuel filler flap and boot are locked automatically. A crash sensor allows them to unlock automatically 10 seconds after an accident. Switchable traction control (ASR) automatically cuts power to wheels which lose grip. If that doesn't restore traction, it gently brakes the wheel individually. Electronic stability control (ESP) also measures bodyroll and steering angle to stop loss of control.