As New York state moves from medical marijuana toward legalizing adult recreational pot, Canada already has. Some problems are similar and the issue of how do you tell if a driver is stoned is one of them.
Niagara Regional Police Chief Bryan MacCulloch, says a specially-trained officer has to be called into render an expert opinion the driver is under the influence and should have a blood test.
"We were arresting people for being under the influence of drugs before the law came into effect and so the fact that we're arresting people now is no different in that respect," he said.
There's also the potential problem of officers showing up to work stoned.
"There's some self-policing that will go on. Obviously, the job is dangerous enough as it is, with enough safety and health issues that you don't want anybody that's not on their game to be involved in calls for services," said MacCulloch.