Justice Minister Jody Wilson-Raybould's preferred roadside cannabis testing device won't be deployed in the city she represents in Parliament.

Today, the chief of Vancouver police, Adam Palmer, told CKNW Radio's Lynda Steele Show that his department won't be using the portable Drager DrugTest 5000.

“There may be other agencies in British Columbia that will deploy it, and other places in Canada, but our experts have looked at it, and it doesn’t meet our requirements so we’re going to pass on this one,” Palmer said on the air.

Wilson-Raybould is the Liberal MP for Vancouver Granville.

There's a two-part component to the Drager DrugTest 5000: first, there's a saliva swab and then it's subjected to a reading.

This can only be done if an officer has reasonable grounds to suspect the motorist has consumed cannabis.

If the motorist tests positive for THC at the roadside, the person can brought back to a police station for further examinations. This must occur before charges can be laid.

The Drager DrugTest 5000 has been criticized for not operating optimally in cold weather.

In addition, it doesn't measure impairment. Vancouver lawyer Sarah Leamon has repeatedly stated that it only determines if there's tetrahydrocannabinol (THC) in saliva.

On September 16 at the Grassroots Expo for the Cannabis Curious, Leamon joined former West Vancouver police traffic expert Grant Gottgetreu in a panel discussion about drug-impaired driving.

Both expressed a fair amount of disdain for the usefulness of Drager DrugTest 5000, with Gottgetreu mocking it as the "Dorito" device.

Under Bill C-46, which passed in June, drivers can be busted for drug-impaired driving with as little as two nanograms of THC in their system. That's lower than the threshold in other jurisdictions.

THC can be stored in blood, fat cells, and saliva for a considerable length of time, which could make anyone using medicinal cannabis vulnerable to testing positive on the Drager device.

Gottgetreu predicted that the criminal prohibitions will eventually be augmented by IRPs—immediate roadside prohibitions—under a provincial statute.

That will free police from the hassle of bringing someone back to a police station for extensive testing for cannabis impairment.

However, Gottgetreu acknowledged that anytime an IRP is issued, it will be attached to a motorist's driving record and end up in a database.

Once that happens, he said, this information could be obtained by U.S. customs officers at the border by merely conducting a search of a motorist's licence plate.

Anyone who confesses to consuming cannabis to a U.S. border official can be banned from entering the United States.

Meanwhile, Leamon expressed doubt whether the amendments contained in Bill C-46 will even survive a constitutional challenge under the Canadian Charter of Rights and Freedoms.