A new national study has revealed sharp increases in the detection of cocaine and cannabis among drivers suspected of driving under the influence of drugs in Ireland, highlighting an emerging road safety challenge and the need for targeted prevention strategies.1 Published in the journal Traffic Injury Prevention, the study analysed toxicology results from 9,369 drivers who were tested by the Medical Bureau of Road Safety between 2012 and 2018. Researchers examined trends in the detection of cannabis, cocaine, amphetamines, methamphetamines, benzodiazepines, and opioids, both individually and in combination, among motorists suspected of driving while impaired.

Cannabis was found to be the most frequently detected substance throughout the study period, with nearly one-half of all drivers testing positive. Benzodiazepines were the second most commonly detected drug, followed by cocaine and opioids. Notably, after accounting for age and sex, cocaine positivity increased by 21% each year, while cannabis detection increased by 13% annually. In contrast, detection of benzodiazepines and amphetamines declined modestly, and opioid detection remained relatively stable. The study also found growing evidence of polydrug use. Detection of cocaine alongside cannabis increased by 25% each year, while detection of cocaine combined with benzodiazepines also rose significantly. By 2018, the rate of drivers testing positive for both cocaine and cannabis had more than tripled compared with 2012, suggesting an increasing trend towards the use of multiple impairing substances.

Men accounted for more than 80% of drivers tested and were considerably more likely than women to test positive for cannabis, cocaine, amphetamines, and methamphetamines. Women, however, were slightly more likely to test positive for opioids. Younger adults were disproportionately represented among drivers testing positive for illicit drugs, reflecting broader patterns of drug use that have been observed in Ireland and internationally.

Driving under the influence of drugs is a major contributor to road traffic collisions because psychoactive substances can impair attention, reaction time, decision-making, and motor coordination. The authors note that the increasing availability and potency of cocaine and cannabis may further elevate risks on Irish roads, and that the findings of this study have important implications for road safety policy. They argue that continued roadside drug testing, enhanced enforcement, and targeted public education campaigns are essential to discourage drug-driving. They also highlight the importance of monitoring emerging patterns of polydrug use, which may result in greater impairment than the use of a single substance alone.

1         Durand L, O’Kane A, Maguire R, et al. (2025) Drug and polydrug detection in drivers suspected of driving under the influence of an intoxicant in Ireland 2012-2018: a national repeated cross-sectional study. Traffic Inj Prev, 27(6) [Early online]: 647–655. Available from: https://www.drugsandalcohol.ie/44249/