Mr. Declan Naughton:

There is evidence that when one pairs any illicit drug with alcohol it has an exponential impact on one's driving. This happens even when one combines alcohol with fatigue and no other drugs or toxicology are involved. Even trace amounts can cause impairment to driving. The ultimate question from a road safety perspective is whether something affects driving. Will there be challenges? We all know that road traffic legislation is extensively challenged, so we will no doubt have the same experience going forward.