We all know that one person who would bet their entire family’s life over the fact they think they can drive even better under the influence of alcohol.
When it comes to weed however, there isn’t nearly enough science to definitively say that driving while high is a one-way ticket to the funeral home. In response, there aren’t nearly the same level of terrifying posters, traumatic documentaries and level of taboo surrounding driving under the influence of marijuana.
Let’s throw the disclaimer in here now: we do not condone or support driving under the influence of any mind altering substance, including cannabis. As cannabis heads toward a future where it may become as commonplace as a glass of wine to cap off the night, the questions around what we can and can’t do high become more and more pressing.
Driving While High
Driving soon after using marijuana is not a good idea. Cannabis impairs your senses and mind, making your reflexes slow and making it harder to focus or make decisions. This goes without saying, but you really shouldn’t be driving a fast death trap on the road with other people.
Still, there are problems with a blanket statement like that.
In America, if your blood alcohol content (BAC) is 0.08 percent or higher, you are considered cognitively impaired at a level that is unsafe to drive and is illegal. With marijuana, there isn’t a national limit and the laws about driving under the influence of the drug vary per state.
Steven Davenport, an assistant policy researcher at the nonprofit Rand Corp., who specializes in marijuana research, told NBC News, “You can’t legalize a substance and not have a coherent policy for controlling driving under the influence of that substance,”
In Colorado, one of the first states to legalize, it took three years of debate in their government for them to follow a type of “per se” law, which doesn’t allow people with a certain amount of marijuana in their system to drive. Colorado law says that “if a person has more than 5 nanograms of delta-9-THC per milliliter of blood, a court or jury can infer that they are impaired.”
In Rhode Island, Pennsylvania and Indiana, it is illegal to drive at all after you have smoked marijuana and have any amount of THC still in your system.
However, the main problem that plagues any policy around driving while stoned is that there is still no way to tell not only if a person has THC in them when they are pulled over, but also how much is in their system.
The Breathalyzer Problem
While some companies have begun to set up and try to create a marijuana breathalyzer, there is still not a uniform device to figure out THC levels. In Canada, there is currently an oral liquid test that is used by police to try and deal with pot users on the road. Vice Canada has said that this test has reportedly been problematic in its practice as weed and THC can stick around for some time.
The effects after THC enters your body tend to last around two to three hours (depending on the dose), which means you probably won’t be very high if you drive a couple of hours after smoking. However, the THC in your blood will probably stick around and can be found nearly a full day after your last smoke session.
Lynn told NPR that it’s “kind of like putting together more than a dozen Olympic size swimming pools and saying, ‘Hey, go find those 10 specific drops of water and in those 10 pools put together.’
Lynn’s device “measures THC in breath to levels as low as 1 trillionth of a gram, or 1 picogram per liter of breath (1pg/L). This is the sensitivity required to measure recent marijuana use throughout the 2-3 hour window of peak impairment identified by researchers.” That’s very small and very difficult.
But Do You Drive Better When You Are High?
Driving under the influence of anything that changes your brain chemistry doesn’t make you better at doing so. Most of the reason you probably believe you are a better driver is because you probably aren’t aware enough to objectively tell how you are doing. Still, driving under the influence of marijuana is way safer than under the influence of alcohol.
Benjamin Hansen, an economist at the University of Oregon in Eugene and at the National Bureau of Economic Research, has studied marijuana legalization in relation to driving accidents and found that while light, the research isn’t nearly as grim.
A review of 60 studies presented in 1995 at the International Conference on Alcohol, Drugs and Traffic Safety found that driving after marijuana use impairs “all the cognitive abilities needed for safe driving, including tracking, motor coordination, visual function and divided attention,” according to Live Science.
However, compared to alcohol, stoned drivers are more likely to take greater precautions on the road and are less likely to be saddled with the physical effects of being drunk.
“They’ll drive slower, they’ll follow cars at greater distances, they’ll take some actions that at least somewhat offset the fact that they’re impaired,” Hansen told Live Science.
Hansen even found that after medical marijuana laws were passed, states saw a dramatic decrease in traffic fatalities involving drugs and alcohol. He and his team hypothesized that people are just less likely to drive while high and that if they do, they’re going to be more careful.
While science doesn’t point to roads becoming an even more dangerous place with the introduction of higher drivers, there isn’t a lot of science to go off of.
Limits on THC-levels are still up in the air in many states are bound to change as more states legalize. At some point, the federal government will have to step in and set up a limit.
However, until that day, it’s probably best to try and avoid driving high, or at least be really careful.