If a collision should occur, intelligent sensors trigger off the occupant restraint systems at the correct moment. The heart of the system is the airbag control unit, which decides whether or not the airbag should be inflated and ignites the safety belt pretensioner and the airbag inflating system according to the nature and severity of the crash. This system has two decentral sensors and is capable of determining the pattern and violence of a frontal impact at a very early stage.

Since these sensors, which measure acceleration, are located in the vehicle’s front impact-absorbing zone, they are referred to as ‘up-front’ sensors. They supply signals to the control unit that enable it to detect the severity of the impact as early as possible.

Further information to enable crash severity to be measured and plausibility checked is obtained by measuring vehicle deceleration in the central control unit.