CAROL STREAM, Ill. (WLS) -- The Carol Stream Police Department is at the forefront of a saliva testing program to measure marijuana impairment in drivers.
The simple test produces almost immediate results, but police say the technology is far from perfect. Marijuana is a complex drug and a single roadside test may never be reliable on its own to measure a driver's impairment.
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"We don't have an oral fluid test that's been completely approved by the state police or that's going to be admissible in court, that is what we are trying to do here," said Sgt. Brian Cluever, Carol Stream Police Department.
Being tested on a voluntary basis only, it takes about five to 10 minutes to collect a sample from a person's tongue.
"It will give us an immediate result in about five minutes if there is a presence of a certain drug in someone's system," Cluever said.
While it might detect the presence of pot, police and toxicologists said there is no way of knowing what the presence means in terms of a level of intoxication. Unlike alcohol, which is one chemical consumed in one way and which leaves your body in a predictable way, marijuana is complex.
"Cannabis is not one chemical, it's multiple chemicals," explained Dr. Jenne Nikolaides, Rush Medical Center toxicologist. "We largely think of THC as the chemical that intoxicates people, but we don't know if that is true."
To add to that complexity, Nicolaides said marijuana stays in your system for a longer period of time.
While lawmakers have determined levels for marijuana impairment, Cluever said numbers are arbitrary and not backed by science. With pot set to be legal in just a few months, Cluever said the law is outpacing science and police are not ready.
"We can't rely on technology to get us where we need to be at this moment," he said.
Cluever said for the time being, police training is the best way to determine if someone is too impaired to drive.
He and doctors agree that even if tests become more accurate, it is unlikely they alone will hold up in court.