The New Brunswick government will impose strict limits on cannabis use in the province when the drug becomes legal next July.

Smoking it will be banned in public places under legislation to be introduced in the coming days.

Adults will be allowed to carry up to 30 grams, but there will be no limit on what they can keep in their homes.

Marijuana will have to be stored in a locked container or locked room in a user's home.

- NB Liquor to sell recreational cannabis in stand-alone pot stores

- Where the pot shops will go across New Brunswick

"The health and wellness of all New Brunswickers is the government's top priority," said Health Minister Benoît Bourque.

The government will also amend the Motor Vehicle Act to create a three-step test for drivers who are impaired by cannabis use. Drivers suspected of being impaired could have their licences suspended on the spot at the side of the road.

The first step in the test is based on "a kind of gadget," as Public Safety Minister Denis Landry calls it, that some critics say is not reliable.

The device, piloted earlier this year in seven communities across Canada, measures the amount of THC, the active ingredient in cannabis, in the driver's saliva.

Some defence lawyer groups say the test is not 100 per cent reliable because THC can show up in the body for a month after cannabis use.

"How good will it be in court?" Landry said to reporters. "If you look at the breathalyzer [that tests for alcohol], some people go into court and contest it.

"The same thing will probably happen with this and it will be for the court to decide. I'm no lawyer. I'm not a judge . … It's not for me to determine if it's OK or not."

Landry would not say what legal advice the province had from lawyers in the attorney-general's office about the enforceability of the new law.

Straight-line test

"That's not really something I have the liberty to talk about," he said.

The second step in the test would have an officer assess a driver by asking them to walk in a straight line, for example. The third possible step would be a blood test.

Landry said 18 officers in New Brunswick are now trained to detect cannabis impairment and the province will train more if that's needed.

Drivers who face short-term and administrative licence suspensions could have their vehicles impounded and will pay extra fees to get their licences reinstated.

There will be zero tolerance for new drivers and those younger than 21 who break the law.

A scramble for regulation

The legalization of recreational cannabis by the Trudeau government in Ottawa has forced provincial governments to scramble to set up retail and regulatory regimes before next July 1.

Dr. Jennifer Russell, the acting chief medical officer of health, says she hopes the new measures will help lower the rate of cannabis use among young people.

"We would not want to see those numbers go up," she said.

She said the number of young people smoking tobacco has gone down and she'd like to see cannabis use drop too, despite legalization.

"I think we have a good chance of success but we do have a lot of work ahead of us. I don't take any of this lightly."

The Gallant government has vowed to tightly regulate recreational cannabis use once it's legalized by the federal government next July 1. The legal age for possession and consumption in New Brunswick will be 19.

NB Liquor will run a network of up to 20 retail stores where marijuana will be sold, but the product will only be under glass, and people below the age of 19 won't be allowed in the store.

Provinces eyeing revenue

At the same time, the government says legalization offers job-creation opportunities in sectors such as growing and processing. The province could also see increased revenue.

Russell would not answer directly when asked if her public-health efforts to reduce consumption were at odds with those goals.

She said her officials have been part of all the discussions within the government.

"Public Health has been at the table," she said. "That's all we can hope for at this point."

Clarification : An earlier version said incorrectly that adults could possess up to 30 grams of marijuana when the drug is legalized. In fact, the provincial rules say adults can carry up to 30 grams but there is no limit to how much they can keep locked up at home.(Nov 07, 2017 12:31 PM)