The marijuana lobby likes to say that marijuana isn’t as dangerous as alcohol. Technically speaking, that may be true. But the reality of drug and alcohol use is that danger comes in many ways. The effect on driving is the biggest one.
Driving under the influence of marijuana, the most common driving-under-the-influence drug after alcohol, is dangerous. A 2012 meta-analysis in the British Medical Journal found that driving under the influence of marijuana “significantly increased risk of motor vehicle collisions compared with unimpaired driving,” and especially for fatalities. People who smoke marijuana and drive are twice as likely to cause a fatal crash compared to clean and sober people. The same study related that the risk of a car crash for people with a blood alcohol concentration of 0.8, the legal limit, is about 2.7 times higher than for a sober driver. So, not a whole lot of difference.
The study also showed that:
- Cannabis impairs cognitive and motor task abilities necessary for safe driving
- Drugs other than alcohol are increasingly found in injured and fatally injured drivers
- In some jurisdictions, marijuana has surpassed alcohol in DUIs among young people
And, just like with alcohol or any other drug, the more pot you smoke, or the stronger the weed, the more likely you are to crash your car.
Drugged driving poses a widening threat. The reality of getting high is that many people use drugs and alcohol together. Drinking beer and smoking weed is very commonplace partying. And it’s particularly dangerous for driving. A study about combined alcohol and marijuana use and driving found that the two used together caused severe impairment for driving, particularly in slowed reaction time.
A 2012 study in California showed that twice as many weekend nighttime drivers test positive for drugs, with as many using marijuana as alcohol. A national survey in 2007 showed that weekend night-time drivers in the United States were seven times more likely to be using drugs compared to alcohol. In general, research shows that the percentage of fatally injured drivers who test positive for drugs is going up.
Determining the level of drug use that causes impairment, or that compares to illegal blood alcohol concentrations, has proven very difficult. So, some States (Arizona, Delaware, Georgia, Indiana, Illinois, Iowa, Michigan, Minnesota, Nevada, North Carolina, Ohio, Pennsylvania, Rhode Island, South Dakota, Utah, Virginia, and Wisconsin) have passed “per se” laws: It’s illegal to drive if there is any detectable drug level in the driver’s blood.
With the legalization of marijuana, more people will be smoking marijuana, so drugged driving will likely increase. The marijuana lobby likes to suggest that more people smoking weed will mean fewer people drinking – therefore, less drunk driving. But researchers say there’s no evidence of that. So, we will probably have an increase in drugged driving while drinking and driving remains the same. If so, it follows that drinking and drugging while driving may increase. That’s not a good situation, to put it mildly.