Road-works almost always mean a restriction of the space available for the road users and thereby also a reduction of the passability. The passage of road-works is acomplicated situation for the driver and therefore poses high demands on the traffic controls used (signs, channelling devices, etc.).

To avoid disturbances in dense traffic during daytime road works are to an increasing extent carried out during hours at night when traffic volumes are lower. The requirements on the traffic controls are however considerably different during daylight than during night to provide acceptable visual conditions for the road users.

A considerable difficulty for the driver who is passing the work zone in the dark is to obtain a visual impression of sufficient quality despite glare from meeting traffic, yellow flashing lights, and work zone illumination. This is required to get a correct comprehension on which speed to hold and where to place the vehicle when passing the work zone.

Within NordFoU it was decided to carry out a joint Nordic project to investigate how to provide a good visual environment at night time road works and as a part of this how to best avoid/reduce the adverse effects of glare.

The primary aim of the project was that it should result in recommendations as bases for the improvement and coordination of existing regulations in the Nordic countries by giving:

− proposals regarding glare limitation

− proposals for requirements for yellow warning/flashing lights

− proposals for requirements on work zone illumination both with regard to the needs of the road workers and to avoid the glare of drivers

− recommendations regarding specular reflection on wet road surfaces.