Mari Grigaliunas works as the public Information officer for the village of Villa Park, a Chicago-area suburb. As a former newspaper reporter, she has a passion for community journalism and enjoys focusing on the stories that make one community unique. She believes we all have a role as global citizens – and that hers is to share the stories that remind us of that.

Driving While High

As Legal Weed Grows, So Do Stoned Driving Concerns

January 2016


After 42-year-old Brian was pulled over for drunken driving six years ago, ?It was a wake up call,? he says. ?I knew I couldn’t risk getting another DUI.?? Fortunately he didn’t hurt anyone, or himself, but his car was impounded, he lost his license, he served time in a work camp, and when he did get his driving privileges back he had to blow into a device that detects alcohol, in order to start his car.

?All that will get you sober in no time,” Brian says.

In fact, Brian has since quit drinking all together. No more booze, and no more drunken joy rides. Yet, he admits he’s traded in one?mood-altering substance for another. This California resident now eats marijuana edibles (chocolate laced with marijuana) daily, getting high regularly.

And then? He often gets behind the wheel and drives.

?But I never feel like I’m impaired in the slightest,? Brian says.

39-year-old Kevin agrees. “When you’re driving drunk you have no?reflexes,” he says. ?Your reaction time is slower with alcohol. Driving high doesn’t impair you like alcohol does. Or at least it doesn’t seem like it does.”

Kevin, who lives in the Midwest, says he hasn’t driven stoned in years. “But there are other people driving high all the time right now,? he says, ??and we don’t even know it. ?So if pot becomes legal where I live, I don’t think we’d see much of a difference on the roadways.”?

Brian and Kevin are just two of millions across the country trying to navigate an American marijuana revolution. Currently, 23 states and Washington D.C. have laws legalizing marijuana in some form. Government studies estimate that, as a result, nearly 2.5 million more people in the U.S. have become regular marijuana users in the past few years.

At the same time, questions and concerns are being raised at every turn. Parents, for example, worry what effect legalized pot will have among teens. After all these years of being called a ?gateway drug??is that no longer true?? For those using the drug for prescribed, medicinal reasons, many are asking, ?How do we standardize dosages?? And others suffering from debilitating diseases in states without medical marijuana legislation think legal access is taking too long.

And then there’s the issue of ?stoned driving,? or ?driving while high.? How dangerous is it? How much pot is too much, in terms of operating a motor vehicle? How is it being monitored? How can it be monitored?

The prevalence of drugged driving

Statistics show that many Americans seem to have no problem driving under the influence of drugs:

* Between 2007 and 2014, illicit drug use by drivers has risen 25 percent, according to the National Highway Traffic Safety Administration.

* According to a 2013 National Survey on Drug Use and Health, 9.9 million people ages 12 and older–or 3.8 percent of adolescents and adults–reported driving under the influence of illicit drugs in 2012.

* The National Institute on Drug Abuse says that marijuana is the second most common substance found in the blood of impaired drivers, behind alcohol.

* Those who drive under the influence of marijuana are more likely to be involved in a car crash than those who don’t drive high or stoned. A 2011 report published in the British Medical Journal found that driving under the influence of marijuana made a person almost twice as likely to be involved in a car crash than unimpaired drivers.

One of the most obvious places to examine the issue is Colorado, where consuming marijuana became legal in 2012.

According to the Colorado State Patrol, the number of fatal or injurious crashes investigated by state troopers involving alcohol or drugs rose from 480 in 2013 to 513 in 2014 when retail shops began selling recreational marijuana. That’s almost a 7 percent increase.

Due to the fact that the Colorado State Patrol says it doesn’t differentiate between alcohol and drugs when determining the causes of car crashes, it’s impossible to concretely attribute these collisions to marijuana legalization. As a result, Colorado legislators have proposed monitoring marijuana-driving offenses. A bill up for debate in the 2016 session seeks definitive answers.

One of the authors of the bill, Colorado Representative Jon Keyser says, ?The motivation is really to be able to have a real discussion with real numbers and real data?if this is a problem we definitely need to address it, but right now we can’t even say if it’s a problem.?

Determining marijuana levels in the body

But marijuana levels can usually only be determined through blood tests, not through an immediate roadside test like a Breathalyzer?which is used to test for blood alcohol concentration (BAC). There’s currently no form of a roadside blood test, so if someone is pulled over for driving erratically law enforcement agents usually instead look for visible signs of impairment. Otherwise, police officers say they have to rely on the potent stench marijuana leaves behind.

According to the Colorado Department of Transportation, while state law specifies a driver with five nanograms (a nanogram is one billionth of a gram) of active THC (the psychoactive substance found in marijuana) in his or her blood can be prosecuted for driving under the influence, law enforcement officers, again, have to base arrests on observed impairment. Colorado law enforcement agencies have something they call ?drug recognition experts? on staff who are trained to detect impairment from a variety of substances.

Sam Cole, Safety Communications Manager for the Colorado Department of Transportation, explains that when an officer observes a driver who appears to be impaired, ?They provide the standard sobriety roadside test for that person,? Cole says. According to the National Highway Traffic Safety Administration, the three components of those tests are the one-leg stand, the walk-and-turn test, and horizontal gaze nystagmus. Horizontal gaze nystagmus ?measures the involuntary jerking of an individual?s eye, which can be exacerbated if one is intoxicated,? according to However, the standard field sobriety tests have been described as ?useless? in identifying drivers impaired by cannabis.

Cole says that if the driver fails the standard road sobriety tests, he or she is arrested. Once arrested, the driver must submit to a blood test, which is either done at the police station or in police vans equipped for taking blood. The blood is then submitted for a toxicology test, which does not provide immediate results like a Breathalyzer for alcohol would.

Scientists are hard at work trying to develop a Breathalyzer for marijuana detection but it might be years before a truly effective and efficient one is ready for widespread use. Researchers at Washington State University in Pullman are developing a hand-held device that police officers can use to detect THC in the breath, through a technology called?ion mobility spectrum. Other researchers in Colorado, Canada and Europe are all working on similar prototypes.

Another challenge is that THC presence in one’s system is different than alcohol. For example, for heavy marijuana users measurable amounts of THC can be detectable in the body days or even weeks after the last use, and long after any psychoactive effects remain. ?This can make it difficult to connect the presence of THC in a person with that person’s current state of impairment.

Emergence of oral fluid testing

But there’s also another new technology that’s emerging more quickly, to help law enforcement officials indicate whether a driver has recently consumed marijuana that’s causing impairment. It’s called oral fluid testing and, like a Breathalyzer for drunken driving, it can be used quickly on the roadside. This technology can differentiate from marijuana that’s been newly entered into a user’s system, rather than the remains of usage from days or even weeks previously.

It works like this:?the inside of the driver’s mouth (tongue, gums, inside the cheek, etc.) is swabbed for saliva, and a one-milliliter sample is then placed inside a portable reader. Chemicals in the machine break down the saliva and test it for the metabolites present in drugs. Results are ready almost immediately; some readers can produce an exact drug concentration amount, similar to a blood alcohol concentration result with a Breathalyzer.??

We Save Lives, a coalition working to prevent drunk, drugged and distracted driving, reports that currently law enforcers in Australia, Belgium, France, and Germany use oral fluid testing to prove impairment via drug use. While oral fluid testing has been available in some capacity for more than a decade, the medical journal Clinical Chemistry states that only recently, within the last five years or so, have oral fluid tests undergone both technological and scientific advances that make them truly usable roadside.

Cities in 14 U.S. states are either testing or considering using roadside oral fluid testing, including California, Vermont, Arizona, Tennessee and Michigan. Still, the Department of Transportation hasn’t approved it ?as a legitimate method of drug testing, noting significant limitations such as high costs, limited scope, lack of sensitivity to variables in the field, and unacceptably high rates of false positives.

One of the problems is that THC is so dissolvable in fats and lipids that it has the tendency to stick to the oral fluid testers, affecting the accuracy of the device. And some law enforcement officials fear that this new technology will be subject to legal challenges that could lead to the results becoming inadmissible in court. Others say these devices are require far too much time-consuming training for officers to be able to effectively operate them.

In addition, since Australia implemented oral fluid testing in 2004, the devices have been described as “terrible.”

Still, proposed legislation and research in California, Ohio, Michigan and Canada aims to further study these devices for effectiveness and improvement, in hopes that law enforcers will be able to begin readily utilizing the technology soon.

How much is too much?

The bill establishing the five-nanogram threshold took effect in Colorado in May 2013 and was met with plenty of criticism?on both sides. Some argued that a limit of five nanograms of THC per milliliter of blood is too high, while others believe it’s too low.

?If there was a legal limit for pot consumption, and I knew that if I was over that limit I would end up in the same situation as the DUI–I would never, ever do it,? says Brian about his edible-eating. ?Although 18 states have set limits on marijuana intoxication, Brian doesn’t face a legal limit in California.

But Brian also believes the wide variation in methods of marijuana consumption create difficulties for enforcing a blood concentration limit. ?How many brownies will create five nanograms of THC in one’s blood, compared to how many drags off a joint?? he asks.

Even Colorado?s Cole isn’t sure how the limit translates in real consumption terms. ?Since we are the first state in the country to legalize the use of recreational marijuana we are still new at this,? Cole explains.

Brian claims that he knows his own limits. He can recount a time or two in the past two years, since he’s become a regular marijuana user, when he consumed too much?so much so that he had trouble walking.

?If I got in the car in that condition, that would be a problem,? Brian acknowledges.

Kevin adds, “I never got to the point where I didn’t have my faculties when I smoked pot. Some people do though. They get neurotic and paranoid. Those people definitely shouldn’t drive. I?ve seen people freak out while they?re stoned, become essentially paralyzed from the high. They start swaying back and forth. Crazy stuff. I can’t imagine what they’d be like on the road. Not good.”

J.T. Griffin, MADD?s (Mothers Against Drunk Driving) Chief Government Affairs Officer, knows sobriety check points work to combat drunk drivers, but he says checking for drugged drivers is new territory.

?I think it would be great if you could make it as simple as?[officers] were able to make a quick determination at the side of the road and make an arrest,? Griffin says, but he thinks more research on the impairment effects of marijuana is necessary to formulate an effective plan to reduce drugged driving.

Seeking answers, and solutions, that make sense

The National Institute on Drug Abuse (NIDA) and the National Highway Traffic Safety Administration are collaborating in a groundbreaking study that aims to provide the information law enforcement, policy makers and citizens throughout the country need.

?This is the first time ever that an illicit drug has been tested at the University of Iowa,? Marilyn A. Huestis tells The Reporters Inc. She’s spearheading the project, which is designed to test the effects of inhaled cannabis on driving performance using the National Advanced Driving Simulator. (In Iowa, marijuana is completely illegal, except in the form of Cannabidiol for the treatment of intractable epilepsy.)

Huestis, the Chief of Chemistry and Drug Metabolism at NIDA, has wanted to conduct this type of study for more than a decade. The driving simulator allows researchers to gather information about driver performance and behavior that isn’t feasible in the real world.

?I think it’s absolutely critical we understand the effects of cannabis with or without alcohol because often they are taken together,? Huestis explains.

She says that while real-world studies about traffic crashes and driver marijuana use exist, testing only the effects of marijuana is more challenging because there is much less data.

The study is testing men and women between the ages of 21 and 55 on six different drives, designed to test cannabis inhibition. Variables include a driver’s ability to pay attention to directions, risk taking, ability to stay in a lane, and maintaining an appropriate driving distance in urban, highway and rural settings, among others. Individuals are either given marijuana, alcohol, placebos or one of several combinations of alcohol and marijuana.

Researchers test each participant’s alcohol and THC (the active ingredient in marijuana) levels via blood and oral fluid tests both before and after each drive.

Preliminary results are now in. The study has found that drivers with only alcohol in their system showed impairment in the categories of ?weaving within the lane,? ?how often the car left the lane,? and ?the speed of their weaving.?

Drivers with only marijuana in their system ?only demonstrated problems weaving within the lane.?

The study also reported that drivers with 13-nanograms of THC in their blood stream ?showed increased weaving that was similar to those with a .08 breath alcohol concentration, the legal limit in most states.? Again, currently the threshold of impairment in Colorado (and Washington) is five nanograms of THC in a driver’s bloodstream.

MADD doesn’t have an official stance on the five-nanogram limit, or on oral fluid tests, but ?The big question with a test like that is will it hold up in court,? Griffin says.

While MADD has just revised its mission to include ?Help fight drugged driving,? Griffin explains, ?We really believe we can eliminate drunk driving in America and we have a plan to do that. But when it comes to marijuana, the plan is still in the works.?

The debate about marijuana and what role it plays in society? medical, recreational or illegal?will likely continue for years to come, but most everyone agrees that the science behind drugged driving simply needs to catch up.

?It’s very critical to have this data,? Huestis says.

Perhaps Kevin’s hazy recollections show the need most clearly.

?I first drove stoned when I was 18, ? he says. ?My friends and I used to get high and go for drives and smoke while we were driving. That was the point of the drive. We thought it would be fun. And it was! I never thought that when I was high and driving I was unfocused or endangering my life or anyone else’s. I just felt happy. I felt in control, unlike driving drunk. But looking back I would say it wasn’t safe at all.?

Kyle Kvamme contributed to this report.

Mari Grigaliunas can be reached at


2 people commented on "Driving While High"
Feel free to join the conversation and leave a comment as well.

  • Cheryl Tvrz says:

    Thank you for another great article!

  • T Zitzka says:

    Great article…great content with interesting facts. In my community there are some cannabis use but meth is a bigger issue. So many young lives lost for no good reason. Very sad.

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