Weed’s impact behind the wheel is a controversial subject. A quick search on the internet will bring up a report that marijuana doesn’t affect a person’s ability to drive. The report directly below will cite a study suggesting that driving while high is akin to driving while drinking, while texting, and while applying mascara with your toes.
But the truth appears to lie, as it often does, somewhere in the middle. Driving while high isn’t as dangerous as driving while drunk, but it’s not as safe as driving while stone-cold sober, either.
How Weed Influences Driving Reaction Time
Weed impacts our ability to relax; that’s why we like it. A few puffs and that twenty-page proposal we have due in the morning doesn’t seem like that big of a deal. After all, there’s lots of other careers. But weed also impacts out ability to react, something not exactly ideal when behind the wheel.
In short, marijuana causes our reaction times to slow
Per a study presented at the International Conference on Alcohol, Drugs, and Traffic Safety, the cognitive abilities needed to drive are each impacted by marijuana. It affects tracking, visual function, attentiveness, and motor coordination. It can also affect decision-making, leaving us more likely to choose to engage in risky behind-the-wheel behavior, things like cutting off another driver to get to an exit ramp.
Yet even with the above, how marijuana impacts driving in the real world is trickier. Sure, it can leave us less attentive, but so can road rage or holding a cup of coffee or fuming over an argument with a loved one.
A 2009 study published in the American Journal of Addictions found that, in simulation tests, cognitive impairments were modest in regards to driving. Most often, these involved drivers driving at reduced rates or taking longer to respond to emergency situations.
Statistics are largely a black and white issue: stats back up theories and move those theories into more factual categories. However, when it comes to driving while high, the stats don’t prove (or disprove) all that much.
A person who gets in a car crash and tests positive for marijuana may not have been actively high at the time of the incident.
They may have smoked the night, the day, or the week before. Thus, when stats say a driver “had marijuana in his/her system” they aren’t saying “the driver was high.” At least not every time.
Many accidents reveal drivers with both alcohol and THC in their system. As discussed in other articles, alcohol does indeed compound the effects of THC. If you drink and smoke, you’ll be a much worse driver than if you just imbibe in smoking alone. But alcohol – drinking and driving – shoulders a great deal of the blame. The jury isn’t out on whether or not alcohol impacts a person’s ability to drive. The verdict is in and that verdict is, “Yes, drunk driving is definitely bad.”
One of the reasons why alcohol’s effects can be proven is because a BAC tells if a person is drunk; blood alcohol doesn’t stay elevated for days after drinking. Another is that alcohol is tied to underestimation. People who are drunk, especially when they’re moderately drunk, are more likely to incorrectly gauge their ability to drive. They think they’re fine when they’re not.
Weed, on the other hand, tends to do the opposite. Because it makes people paranoid, imbibers overestimate their level of impairment. When driving high, drivers are more likely to drive slow, drive cautiously, drive at safe distances, and drive-thru. Any drive-thru. Another factor in all of this is medical marijuana.
Per Reuters, legalization of medical marijuana doesn’t increase traffic fatalities and, in some instances, decreases them
The researchers behind these studies couldn’t prove why this was the case, but they had a few ideas. One is that people are replacing more dangerous substances with cannabis. Someone who was drinking as a way to deal with back pain, for instance, is now putting down the bottle and picking up the pipe. If a person is no longer drinking, then they’re no longer driving drunk, either.
Other people may replace opiates – drugs that are also dangerous when combined with cars – with cannabis. Weed behind the wheel is the lesser of the two evils, even if it remains a bit evil itself.
DUIs for Weed
In Colorado and Washington, the first two states to legalize, drivers are arrested for DUIs if their blood shows THC levels higher than 5ng/ml. But drivers in these states and elsewhere may be arrested based on decisions by Drug Recognition Experts.
According to Nebraska NPR, Drug Recognition Experts are certified law enforcement agents specifically trained to spot drivers driving under the influence of cannabis and other drugs. Regular patrol officers who suspect a driver is high can call for backup in the form of a Drug Recognition Expert.
Twelve steps exist as part of the expert’s evaluation, steps that are similar to a field sobriety test. The tests assess muscle response, blood pressure, and urine. They involve other steps too, such as asking a driver to tell the officer when thirty seconds has elapsed.
People high on cannabis tend to think time is moving much slower while those on other drugs, like meth, speed it up
Some drivers have tried to challenge these tests in court, arguing that other variables factored into their results. Yet these appeals are often rejected even when taken to the Supreme Court.
Don’t Start Your Engines
In the end, it’s probably safe to say that driving while high isn’t nearly as dangerous as prohibitionists want people to think (and it’s certainly not as dangerous as driving while drunk), yet it’s not without its risks. Weed does alter our ability to function to some degree (but, of course, this differs by type and strain). Anything that does this should be used with caution whenever driving is involved. It’s always better to be safe than sorry. So, if you’re a user, call an Uber.