The chemical testing of intoxicants in driving is the statutory responsibility of the Medical Bureau of Road Safety (MBRS) and I have therefore forwarded the first part of the Deputy's query to the Bureau for direct response. I would ask that he contact my office if no reply is received within 10 working days.
In response to the Deputy's second question, I am happy to clarify that a statutory medical exemption certificate is provided for in law for drivers who have been prescribed medicinal cannabinoids. This form must be completed and signed by a medical practitioner on the Irish Medical Register and should be carried by the holder at all times when driving.
I must stress, however, that this certificate only exempts the driver from normal drug driving offences where a Garda carrying out a roadside test does not form the opinion that the driver is impaired. Where such an opinion is formed, however, the impaired driver may be arrested and potentially charged, irrespective of whether or not he or she can produce evidence of medical exemption.