Officials with Draeger say the marijuana-screening device, Draeger 5000, has made it through 10 months of legal pot in Canada with no complaints from police.

Representatives from the company are in Edmonton this week as part of a conference on combatting impaired driving.

The Draeger 5000 was the first roadside screening device approved by the federal government, and is currently the only one commercially available to police agencies in Canada.

Several concerns have been raised—predominantly from Canadian criminal defence lawyers—about the device’s accuracy, invasiveness and cold-weather reliability.

Draeger’s business development manager for Canada told CTV News Edmonton there have been few issues.

“We've deployed all around the country. We've had not complaints from law enforcement about any malfunction or any weather issues,” said Einat Velichover.  “And I know the devices were used in arrests, and we're seeing the adoption slowly pick up.”

The device is used by police after a driver is pulled over, if the officer suspects the person is under the influence of cannabis or cocaine. A saliva test provides a negative or “presumptive positive” for both drugs. If the test registers positive, the person is taken into custody and subjected to further testing before charges can be laid.

At least one legal challenge has been filed in a case involving a Draeger unit since legalization.

Nova Scotia’s Michelle Gray had her licence suspended for seven days, after failing a roadside test, using the screening device. Gray later passed more in-depth sobriety tests and was not charged.

Gray’s lawyer, Vancouver-based Kyla Lee, is handling the court action. She argues that the roadside units test only blood-THC limits, not impairment, and that the laws that allow them should be struck down.

“The challenge we're bringing on Ms. Gray's behalf, is to the use of the Draeger Drug Test 5000 itself, whether it's constitutionally valid in Canadian law to pull people over, to subject them to these lengthy sobriety tests, on the basis of untested, new technology,” Lee told CTV News Edmonton.

A second cannabis-screening device was approved by Ottawa last month. The company that makes the hand-held SoToxa expects its product to be available to Canadian police agencies in October, near the one-year anniversary of the legalization of recreational marijuana.