PRINEVILLE, OR -- Recreational marijuana has been legal in Oregon for a little more than four months and some law enforcement agencies are still concerned there could be a rise in impaired drivers.

Unlike alcohol, there isn't a breathalyzer for those who may be high on marijuana. One of the best tools police have is a Drug Recognition Expert (DRE). Training is fairly extensive for officers, but Interim Prineville Police Chief Les Stiles says they play a valuable role. "The Field Sobriety Testing (FST) protocol remains the same whether you're under the influence of marijuana, alcohol, prescription drugs, anything. Generally, an officer, because an individual doesn't do well on the FST, they'll take them into custody and bring them down and give them a breath test and they blow under the legal limit; but all of the FSTs indicate that they're substantially impaired. And, that's when the DRE gets the phone call to come in."

These Drug Recognition Experts know the signs to help figure out what is causing a driver's impairment. They evaluate a driver's mental and physical condition and can use tests that analyze breath, blood or urine.

Chief Stiles say his department only has one such officer right now, "Who is also the only officer for all of Crook County. The Sheriff's Office used to have one DRE, but they don't any longer, so that's all we've got. The problem is, this is another one of those unintended consequences of passing measures that the state's not ready to fully support or implement." And, he says he'd like to grow the program. "One of our goals next year, at the Prineville Police Department, that I'm dialing into our budget right now, is a DRE on every patrol team. So, I need three more.