Once Again, Marijuana Positive Drivers Show “No Signs of Impairment”

Another news station has done a test on marijuana smokers on a driving course and has come to two conclusions that we already know:

1. Having marijuana in your system is no indicator of any driving impairment, and
2. Smoking marijuana then immediately driving is going to reduce some people’s ability to drive.

Shortly after Washington legalized marijuana, local news station KIRO took three marijuana-smoking volunteers to a driving test. It was then we met a young woman named Addy Norton, whose driving was only “borderline”, according to an observing drug recognition expert (DRE) police officer, once she had reached 56 nanograms of active THC per milliliter of her blood (ng/mL). Washington had included an unscientific 5 ng/mL per se DUID punishment in its law and the KIRO test provided clear evidence of the worthlessness of the limit for determining actual impairment.

Now, a FOX station in Boston, WFXT, has done a similar test on four marijuana-using volunteers. Before we continue, let’s be clear that the WFXT testing is referring to nanograms of active THC in their urine, not in their blood. At least, I think they are. Toward the end of the piece, one of the doctors refers to metabolites, which is an even-more unscientific method of punishing cannabis-using drivers. This makes comparisons to the KIRO test imperfect.

However, many states use detection of active THC or inactive metabolites in urine as the basis for their zero tolerance marijuana DUID laws. These urine tests, according to WFXT, register a positive result at 50ng/mL. So, we can consider them useful for debunking the idea of zero-tolerance marijuana DUIDs specifically and the idea of stoned mayhem on the freeways in general.

Here are the results of the test – each “run” followed smoking 3/4 gram of Critical Cheese that tested at 22.74 percent THC:

1. Quentin – 36-year-old male, moderate user.
   Baseline = 94ng/mL, “no signs of impairment”
   First Run = “without any significant issues”
   Second Run = “only minor issues”
   Third Run = “more signs of impairment, hitting a cone”
2. Carol – 56-year-old female, daily medical user
   Baseline = 94ng/mL, “only minimal trouble”
   First Run = “she did back into the rear barrier in the parking test”, “She seemed a little bit more confused”
   Second Run = “crashed through several cones”
   Third Run = “more signs of impairment, slowed down significantly”
3. Corinne – 24-year-old female, daily recreational user
   Baseline = 100ng/mL, “no obvious signs of impairment”
   First Run = “failed to stop after the high speed emergency lane change”
   Second Run = ” hit a series of smaller cones on the side of the emergency stop and lane change”
   Third Run = “more signs of impairment, sped up through some parts of the driving course”
4. Don – 65-year-old male, moderate medical user
   Baseline = 104ng/mL, “excelled in the first runs”
   First Run = “knocked down one cone in the slalom”
   Second Run = “only minor issues”
   Third Run = ”more signs of impairment, slowed down significantly”

Dr. Jordan Tishler observed the test and noted that “the sky isn’t falling and not everybody crashed and burned.” Everyone involved with the testing observed that the effects of marijuana on each volunteer was different, with some speeding up and others slowing down. Even at the highest levels of marijuana use, the volunteers were able to successfully complete many portions of the course.

When the story threw back to the anchors at the FOX station, one seemed unable to believe that we wouldn’t be able to set a fixed limit, like alcohol, to determine whether or not a driver is impaired. But this isn’t surprising to anybody who understands how marijuana works in the body. That includes the National Highway Traffic Safety Administration, which has noted since last century that “It is inadvisable to try and predict effects based on blood THC concentrations alone, and currently impossible to predict specific effects based on THC-COOH concentrations.”

The only surprise to me in this test is how the older drivers slowed down in the third run and the younger drivers sped up. Other than that, we found that prohibitionists need to back off the idea that having weed in your system means you’re more dangerous on the road and that tokers need to back off the idea that smoking pot then immediately driving means you’re not more dangerous on the road.