The Calgary Police Service wants more information and more funding for drug impairment recognition training for front-line officers before marijuana becomes legal in Canada.

At a meeting of the Calgary police commission this week, CPS outlined the steps the service is taking following the announcement this week that the Liberal government will introduce legislation to legalize pot by July 1, 2018.

Sgt. Richard Butler, who heads the force's alcohol and drug recognition unit, warned the legalization of the drug in other jurisdictions has been accompanied by a rise in collision rates and costs associated with policing drug-impaired drivers.

"We certainly expect that with the pending legalization of marijuana that those calls for (drug recognition) service are definitely going to increase. We've seen that increase in every state south of the border we've looked at where they've had a legalization of recreational marijuana," Butler told commissioners Tuesday.

"We also expect the collision rates to go up. The same way it did when we cancelled prohibition, when we legalize marijuana in Canada, we're expecting those costs to go up."

Part of the challenge, according to CPS, is that federal funding initially put into place for Drug Recognition Expert (DRE) training in 2008 has gradually dwindled, and now individual law-enforcement agencies must shoulder the cost of training officers, including the costs associated with annual recertification.

Officers trained as DREs administer a 12-step evaluation that can take as long as an hour to complete to determine whether a driver is impaired by drugs. A DRE is considered an expert under the provisions of the Criminal Code.

CPS went from a peak of 17 officers trained as DREs on the force in 2011 to a low of just five officers in 2015.

"We're currently in a rebuilding phase of DRE," Butler said, pointing out that there are now 13 DRE officers on the force and CPS has committed to training 10 additional officers in mid-April.

As with all other Canadian law-enforcement agencies, CPS is waiting to see what shape federal and provincial legislation surrounding legalization will take, specifically when it comes to sanctions or criminal charges for people caught driving under the influence of marijuana.

CPS is also waiting to see the results of pilot projects in other Canadian jurisdictions on roadside saliva tests aimed at detecting drug-impaired drivers.

"We are looking for more information and we're looking for more funding from the federal government to support that. If we get those two things, I'm sure we'll be ready to address whatever happens when it actually comes," Butler said.