The aim of standard-compliant tunnel lighting is to prevent accidents and to ensure the best possible orientation in the tunnel in the event of an incident. The tasks of tunnel lighting have not changed to this day. The question now arises as to whether the changed traffic conditions of the last 40 years place new or different demands on lighting. Has new knowledge been gained in the last decades that can help improve safety? Are the defined visual tasks still appropriate?

The decision to use counter-rotating lighting in the entrance area was made for purely economic reasons (cost effectiveness). Counter directional lighting is approximately 2.0 to 2.5 times more efficient, in terms of illuminance at ground level, than straight lighting, for example.

According to the Federal Office for Spatial Development, the total volume of traffic will continue to increase until 2050, driven by population and economic growth. Compared to the population growth of +21% until 2050, passenger traffic increases disproportionately with +11% and freight traffic with +31%. There is a slight percentage shift to public transport. In absolute terms, however, individual transport will continue to increase.

What has changed in the last 40 years since the tunnel standard was established? What new insights have been gained during this time?