You may have seen last week's minor media tempest regarding a grandfather who had consumed a few drinks and then hopped into the passenger seat to supervise his grandson, the learner driver. They encountered a police road check and grandpa found himself on the receiving end of an Immediate Roadside Prohibition (IRP) for blowing a fail. Who would have thought that the supervisor of a new driver needed to be sober?
Hello? What does a supervisor do? The verb supervise may be defined as "to direct or oversee the performance or operation of." This means that this grandpa had a responsibility to both his grandson and other road users. His job was to insure that the grandson operated the vehicle correctly and to intervene if necessary. There is no doubt in my mind that having a blood alcohol concentration (BAC) of 100 mg% (.10) or more is an abdication of his responsibility.
The legal concept involved here is that of being in care and control of a motor vehicle while impaired by alcohol or a drug. It applies for both Criminal Code and Motor Vehicle Act offences. Grandpa could have been tried and convicted criminally for his actions instead of being dealt with as an IRP. I know, I investigated and prosecuted both an impaired beginner and supervisor out of the same vehicle in the early 1980's.
So, in addition to zero blood alcohol for the new driver, the supervisor needs to have a BAC under 50 mg% (.05). Ideally, the supervisor should have a zero blood alcohol requirement too. I don't imagine that it would be too difficult to amend the Motor Vehicle Act to include this and make the situation explicit.