State-of-the-art technologies today include manual and automatic headlamp levelling, which guarantees for example a constant range of illumination independent of the loading condition of the vehicle. This system is prescribed by law for all new vehicles registered in Germany after 1990. Using level sensors, the state of compression of the suspension is measured on the front and rear axles respectively. The sensors then transfer a signal, which is proportional to the compression of the suspension, to a setting element. A damping unit is located in between, in order to prevent the system from going into operation for quick changes in level during driving. The angular adjustment of the headlamps is realised by geared motors, over vacuum units or electrically regulated expansion joints.
The latest concept of front lighting involves dynamic headlamp levelling which compensates vehicle dynamic pitching motions. The dynamic headlamp levelling is regulated by a microprocessor. The position of the vehicle is measured over mechanical axle sensors or contactless ultrasound sensors. The movement of the body which is hence measured both in the front and the rear serves as input signal for the adjustment of the headlamps. This takes place over powerful servomotors.