In search for the dark numbers. Development and introduction of a controlled roadside survey programme in Denmark.

A country wide 18 month programme of random roadside breath testing was started in 1985 with the target of sampling 100. 000 drivers in Denmark. The key programme element is the mini action in which a sample of only 3-4 drivers are stopped and their breath alcohol is recorded by a police patrol, who also counts traffic intensity. The planning process, the inspection methodology, the co-operation between police and researcher, and the computational model are discussed.