Police seeking quick test to help ID those driving while stoned
Hard to gauge impairment after motorists smoke weed
When marijuana sales become legal in Illinois next year, it will remain illegal to drive while high. But police say they still won’t have the tools to enforce laws against stoned driving the way they’d like.
Law enforcement officials expect a significant increase in the number of people driving after smoking pot. While patrol officers can use Breathalyzers to help check whether people are driving while drunk, they have no approved roadside test to see whether drivers are stoned. Police in Carol Stream are hoping to help change that.
After a false start last year, cops in the western suburb are trying out a roadside test to determine whether drivers have consumed drugs, including cannabis, opiates and methamphetamine. It’s part of an effort to find the best way to reduce drugged driving — a problem that appears to be getting more common, even as drunken driving has been decreasing.
Police are searching for a quick test to help them identify drivers who’ve used marijuana recently, Carol Stream police Sgt. Brian Cluever said.
“This is definitely a step in the right direction,” he said. “I think we’ll eventually get the right answer and the right rules.”
The problem is, there is no scientific standard for establishing impairment based on the amount of THC — the main component of pot that gets users high — in the body. The drug is metabolized very quickly, but remains in the body for a long time, well after the high wears off. That means there may be a long legal fight ahead for any attempt to create a parallel policing system for pot as there is for alcohol.
Illinois law sets the definition of driving impairment from marijuana at 5 nanograms per milliliter of blood, or 10 ng/ml of other bodily fluids such as saliva or urine. The new roadside tests being tested by Carol Stream use saliva.
But the National Highway Traffic Safety Administration cautions that there is no scientifically established measurement of bodily fluids to establish impairment, so such laws are “not meaningful.”
Studies have shown that marijuana can cause slower reaction in braking, problems with staying in the center of the lane, and impaired attention, decision-making and risk-taking. However, the agency added, studies have been divided over whether these often small changes increase the risk of crash involvement.
Blood tests have repeatedly found an increase in the number of drivers testing positive for THC in recent years. In Washington state, where legal marijuana sales began in 2014, a study found an increase in THCpositive daytime drivers from 8% before implementation to 19% one year after. Again, that doesn’t prove impairment, because THC can remain in the blood for weeks after use.
Nationally, more people who’ve used marijuana are turning up dead in car crashes. In 2016, 38% of fatally injured drivers tested positive for marijuana, 16% for opioids and 4% for both, the highway safety agency found.
In response to such findings, Carol Stream police are taking steps to try out two roadside drug tests to screen saliva for drugs in five minutes. In July, officers began using a device made by mLife Diagnostics of Marshall, Texas. Soon, they plan to also start using the SoToxa Mobile Test System, made by northsuburban-based Abbott.
Both devices analyze saliva swabbed from a driver’s mouth to make a preliminary determination whether THC or other drugs are present. The hand-held devices do not measure how much of a drug is present.
Police are not trying to use the device to determine how much THC a person has in their system, nor whether they are impaired. They are merely looking for evidence to support probable cause to arrest the person. The police officer must determine whether the person is impaired.
After pulling someone over for a driving infraction, and speaking with the driver, a patrol officer may check for impairment use the Standardized Field Sobriety Test, a 12-step test that includes walking in a straight line and turning, standing on one leg, and touching one’s nose with eyes closed.
Because those tests were originally designed to detect alcohol, rather than drugs, police have developed specialists to look for drug impairment. Drug Recognition Experts, or DREs, are officers who are trained to run additional field tests designed to detect drug use, such as taking the driver’s blood pressure, temperature and pulse, and testing eye tracking and pupil dilation.
Ultimately, as with alcohol, if police suspect impairment, they may take the driver to the station or to a hospital for a blood draw.
The difficulty with that is police typically need a judge’s approval for a search warrant, and then need a trained phlebotomist to draw the blood, a process that can easily take a couple of hours. By then, studies show, most of the THC in blood has already dissipated, even though the person may still be impaired.
The body breaks down THC out of the blood quickly, but then stores the metabolites in fat. That’s why the roadside saliva tests only check for active THC, which only covers recent hours.
The SoToxa, which also tests for benzodiazepines and amphetamines, is already in use by law enforcement in Canada and parts of Europe, along with a competing device, the Drager DrugTest 5000. Carol Stream police started testing the Drager device last year, but stopped after it didn’t match lab results. One study of 301 drivers in Norway found that the Drager device had a 14% false positive rate for marijuana, and 87% false positives for cocaine, compared with blood tests.
In addition, Hound Labs of Oakland, California, expects to have a marijuana breath analyzer available in 2020 for use by law enforcement and by employers. It is designed to measure marijuana use just within the previous three hours, when impairment is greatest.
Some defense attorneys remain skeptical. They question how reliable the devices are, to what extent they will generate false positive results and whether they will be approved by judges for use in court.
“I anticipate a lot of heated discussion,” former prosecutor turned Arlington Heights defense attorney Moe Ahmad said.
Alabama and Oklahoma already allow use of the
SoToxa device that Carol Stream is using. Michigan police ran a five-county pilot program using the test device last year. Police said the sample size of 92 tests was too small to generate conclusions, but expanded the program statewide this fall.
Unlike in Illinois, Michigan lawmakers passed a law so drivers can be fined if they refuse the roadside saliva test. In Carol Stream, the new drug testing device for now will be used only on those drivers who voluntarily agree to the test, with a signed statement that it won’t be used against them in court, but is strictly for research. Typically, drivers are free to refuse such pre-arrest tests, but can have their licenses suspended if they refuse a blood, breath or urine test after they’re arrested.
Fred Delfino, Abbott’s senior law enforcement liaison, said the device has a proven accuracy of greater than 90%. It tests THC at much higher concentrations than lab tests, he said, so the chances of a false positive are low.
Often, police will only test drivers for alcohol, but the Michigan results showed cases of multiple drug use, Delfino said, demonstrating the importance of testing for drugs.
“Something needs to be done to make our roads safer,” he said.