OTTAWA -- A new Statistics Canada survey reveals an "alarming" number of Canadians have driven a vehicle while high on cannabis or have been passengers in such vehicles.

According to the second quarterly national cannabis survey, 14 per cent of cannabis users who have a driver's licence admitted they got behind the wheel within two hours of consuming cannabis at least once in the past three months.

And five per cent of Canadians over the age of 14 said they've been a passenger in a vehicle driven by someone who'd consumed cannabis in the preceding two hours.

The survey results were released Thursday, just two months before cannabis is to become a legal, regulated product in Canada.

Statistics Canada is conducting quarterly surveys throughout this year as part of an effort to measure the social and economic impacts of legalization.

Andrew Murie, chief executive officer of MADD Canada, called the latest numbers "alarming" -- more than triple the rate of Canadians who drive after consuming alcohol in the preceding two hours.

"I think if you compare it to alcohol, they're shocking," he said in an interview.

However, Murie noted that the federal government has recently authorized more tools to test drivers for cannabis impairment and he predicted the rate of drug-impaired driving will drop once police get those tools operational.

"I think once people get the idea that police do have the tools, that they can detect drug-impaired drivers, especially cannabis, then I think like alcohol with the breathalyzer it'll start to lower those rates."

Part of the problem in discouraging driving while high is that no one can pinpoint how much cannabis needs to be consumed to cause impairment, Murie said, noting that there are too many variables, such as the potency of pot consumed and an individual's tolerance level.

To be on the safe side, he said MADD -- Mothers Against Drunk Driving -- recommends that no one should drive a vehicle within four hours of consuming any amount of cannabis.

According to the survey, men were nearly two times more likely than women to drive high.

The second quarter data found that about 4.6 million people nationally, or close to 16 per cent of Canadians aged 15 and up, reported using cannabis in the prior three-month period. This was similar to what was reported in Statistics Canada's first quarterly survey.

Cannabis use was higher than the national average in Nova Scotia (21 per cent), Ontario (18 per cent) and in the territorial capitals: Whitehorse (23 per cent), Yellowknife (27 per cent) and Iqaluit (33 per cent).

The survey suggests cannabis use is highest among young people -- 33 per cent of 15 to 24-year-olds, compared to 13 per cent of Canadians over the age of 25. Statistics Canada suggests higher usage among young people may account for regional variations, particularly in the territorial capitals where populations tend to be considerably younger than the national average.

Consumption rates in Quebec and Saskatchewan were lower than the national average, at 11 and 10 per cent respectively.

The vast majority of respondents -- 82 per cent -- also said they probably wouldn't increase their consumption once pot is legalized.

The latest data was collected from mid-May to mid-June.