ACP / LUM

Luminance cameras

The lighting requirements of a tunnel are determined by the characteristics of the human eye. The visibility of vehicles and obstacles depends both on the lighting and on the reflective properties of the road surface and the tunnel walls. Tunnel lighting must be regulated in such a way that drivers can safely approach, drive through and exit the tunnel both day and night. Especially when entering the tunnel, a driver must be able to recognize obstacles in good time and stop. Luminance describes what people perceive as brightness and is therefore the key control variable for tunnel lighting. The environment to be measured is set via a lens in the luminance camera. Light from this environment hits the photo element of the camera, which uses this to calculate the luminance and outputs it via the analog outputs.

How tunnel lighting is to be designed and regulated is described in international and national guidelines and standards:

Switzerland: ASTRA guidelines and technical manual for operating and safety equipment (BSA) 

Austria: RVS 09.02 Tunnel equipment  

Germany: DIN 67524 RABT Guidelines for the equipment and operation of road tunnels