Urine and blood samples from 1730 drivers involved in road accidents (July 2012- December 2015) were analyzed for the evaluation of driving under influence of drug of abuse according to the Lombardia Region guideline. The 22.5 % of urine screenings tested positive for at least one class of drugs. 10.6% of the 1730 drivers were under the influence of drug, being blood concentration above the cut-off limit for at least one active substance; the prevalence of illicit drugs in blood was cocaine (5.7 %), cannabinoids (3.7 %), opiates (1.4 %), methadone (1.4 %), amphetamines (0.2 %). Trend in prevalence showed similar percentage (about 5 %) of cocaine and cannabinoids consumption in the last two years. Poly-drug of abuse consumption emerged in the 10.4 % of the positive blood and alcohol was above the legal limit in 47 % of the subjects driving under the influence of drugs.