It is illegal to drive while under the influence of drugs to such an extent as to be incapable of having proper control of the vehicle. Section 49 of the Road Traffic Act 1961, as inserted by Section 10 of the Road Traffic Act 1994 prohibits the driving of a mechanically propelled vehicle by a person while under the influence of an intoxicant. An intoxicant includes alcohol and drugs, and any combination of drugs and alcohol.
The Medical Bureau of Road Safety continues to analyse blood and urine specimens received from the Garda Síochána under the Road Traffic Acts for the presence of a drug or drugs where the level of alcohol determined is under the legal limit, or when a specific request for drug analysis has been received from the Gardaí when the alcohol result is above the legal limit. Prosecution of offences relating to driving while under the influence of drugs is a matter for An Garda Síochána.