Almost 30% of drivers caught driving under the influence of drugs had taken more than one substance at the same time, the latest figures from Belgium’s National Institute for Criminalistics and Criminology (NICC) show. Drivers are increasingly testing for multiple drugs simultaneously. The party drug ketamine is also appearing more frequently in drunk driving.

Last year, the NICC analysed 8,300 (8,289 to be precise) saliva samples and almost 88% tested positive for drugs. The percentage of drivers using multiple drugs simultaneously has risen sharply,  from 20% five years ago to almost 30% today, which is alarming. “Combining drugs significantly increases the risk on the road,” warns the NICC.

Polydrug use

Combined drug use is not only harder to detect, but it’s also more dangerous. The effects of different substances can reinforce one another. The most common combination is cannabis and cocaine, which was found in more than half of the cases (54%). 

Last year, 65% tested positive for cannabis, 48% for cocaine. While only 6% of drivers tested positive for the drug, ketamine is appearing more often in lab results. The NICC says it is no longer just a ‘party drug’ and can cause disorientation and hallucinations, which are extremely dangerous when driving.

‘Party drug’

Ketamine is an anesthetic used in hospitals and veterinary medicine, and researchers are encountering it more frequently in drunk driving cases. However, ketamine is not yet listed in the Belgian traffic law. 

Prevalence of drugged drivers, detected via saliva tests, is increasing, and polydrug use is a particular concern because the combined effects are more complex to predict and assess at the roadside.

Current Belgian traffic law lists only a limited set of drugs (like cannabis, cocaine, and some amphetamines) for roadside saliva screening. Ketamine, new psychoactive substances (e.g., mephedrone), and other emerging compounds are not yet included in roadside testing protocols.

This means that in practice, drug detection is reaching the limits of the rapid saliva tests currently used by police. A lab could identify the drugs, but traffic laws prohibit this.

Alcohol

Also, alcohol remains a problem in traffic. In Belgium, around 9 % of drivers involved in injury crashes were found over the legal alcohol limit. Observational surveys show approximately 1.6 % of all kilometers driven in Belgium are under the influence of alcohol, rising to about 7 % on weekend nights. Alcohol still remains the dominant contributor to impaired-driving fatalities and serious injury crashes across Europe.