As state legislators seek the votes to legalize recreational marijuana, law enforcement officials are calling on officials to pump the brakes.

The state Association of Chiefs of Police says it will take months or years for all police departments to train enough officers to catch motorists who are driving under the influence of legal marijuana. But under current proposals, legal marijuana could be for sale as soon as next January.

To get impaired drivers off the streets, police departments will increasingly turn to their Drug Recognition Experts (DREs).

"I decide if someone is impaired. I make an opinion based on my training and experience that someone is under the influence and is too impaired to operate a motor vehicle," says Sayreville Police Chief John Zebrowski.

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Zebrowski is one of the vice presidents of the state Association of Chiefs of Police. The chiefs want state legislators to hold off on legalization until they can see more crime data from state where marijuana is already legal.

"I want to be able to protect my town, I want to be able to protect the quality of life in my town and I think right now, what's best for my town is for us to say to legislators -- stop. Give it some time," says Zebrowski.

A blood test can detect THC, the main active ingredient of cannabis, but since it stays in the body for days, there is no level to determine intoxication. Instead, police departments have to do a 12-step, hourlong battery of tests conducted by a DRE.

It takes six weeks to train a DRE, and during that time an officer is off the street. The state police force is the only agency that performs the training. Zebrowski says if legalization comes, his 90-person department would need eight to 10 DREs to police the more than 400,000 drivers who pass through Sayreville every workday.

Gov. Phil Murphy and Democratic leaders in the Legislature struck a deal last month on how marijuana would be taxed. A final legalization bill has not yet been unveiled.