With marijuana legalization one big step closer to becoming a reality in Canada, a Vancouver company says it has developed a prototype device for catching drug-impaired drivers.

Canada's next prime minister Justin Trudeau has promised to legalize and regulate marijuana for recreational use, and that's raised concerns about a possible increase in the number of impaired drivers on the road.

Cannabix Technologies president Kal Malhi says recent studies have found that THC — whether smoked or ingested — was expelled through the lungs over a two-hour period.

The challenge is putting the technology in a handheld device that can be used by police as a reliable roadside test.

Malhi says his company has been working on a new device for a year and a half that looks and works much like an alcohol breathalyzer — using technology known as high-field asymmetric waveform ion mobility spectrometry.

"We have gotten to a prototype stage and are working on getting the product out to prototype testing by third parties."

Malhi says he's already in talks with officials in places where the drug is already legal — such as Colorado — but the product is still needs to undergoing third-party testing for accuracy and is at least two years away from being finished.

While the company is based in Vancouver, most of the lab work is being done at the University Florida, said the former RCMP officer turned entrepreneur.

"There is an onus on our government to have system in place if they are going to legalize marijuana ... where safety is taken care of as well," said Malhi.

Current testing for pot impairment used in U.S. states that have legalized pot relies on time-consuming blood tests that detect active THC. Australia uses saliva tests, but they can result in positive tests several days after marijuana use, he said.

"At present, there is no scientific and court accepted tool for law enforcement to gather evidence of marijuana impaired driving to support criminal charges. In addition, the court systems in North America have been reluctant to proceed with criminal charges against drivers arrested for driving under the influence of marijuana without scientific evidence to support such charges," said a statement released by the company.