Driving under the influence of alcohol on Irish roads is well publicised. In 1999, of the 8,476 sampler submitted by the Gardai to the Medical Bureau of Road safety for alcohol analysis, 92 per cent were over the legal alcohol limit.

The results presented in this paper indicate that there has been a significant increase in driving under the influence of drugs in Irish roads since 1987, when 14.6 per cent of samples (under the legal alcohol limit) tested were found positive for drugs. This preliminary study has found that the percentage has risen to approximately 37 per cent. The extensive survey being carried out in 2000/2001 will identify true trends in the types of drugs being taken, their combination with alcohol, and the extent of polydrug use. This work also highlights the importance- of confirmatory analysis in the interpretation of drug screening results.