No suitable method to determine the amount of alcohol and drugs in traffic

In the Netherlands there is no suitable method to measure how much alcohol and drugs someone has used in traffic. Until now, data from the well-known large-scale trap controls have been used for this purpose. However, due to social media, motorists are increasingly avoiding these checks. Moreover, the trap controls only check for alcohol and not for drugs. Measurements based on random checks during regular police surveillance offer opportunities to gain insight into the use of drugs in traffic. However, this working method also has drawbacks, as shown in a test set-up that SWOV carried out in collaboration with the police. This is stated in SWOV's report 'Measuring alcohol and drug use in traffic during regular police surveillance; Pilot study in three police districts'.