In Fatal Traffic Accidents, More Drivers Are Drugged Than Drunk

Two wrecked cars

A new report reveals that for the first time, a higher number of drivers who recently died in car crashes were drugged rather than drunk. An analysis using 2015 information on fatal crashes in the U.S. found that 43% of these drivers had used a legal or illegal drug compared to 37% who exceeded the legal limit for alcohol.

37% of the time, the drug found was marijuana. Amphetamine was second at 9.3%. No differentiation was made between legal and illegal drugs in this analysis so the amphetamine consumed could have been Adderall, methamphetamine or some other form.

It’s not surprising that marijuana is showing up in more test results. At this time, more than two dozen states permit the use of marijuana for medical purposes and recreational use is now permitted in Alaska, California, Colorado, Maine, Massachusetts, Nevada, Oregon, Washington and the District of Columbia. This upward trend of positive test results is likely to continue.

Determination of Impairment

It’s much harder to determine impairment of a drugged driver than a drunk one. Nationally, the limit for a blood alcohol concentration is .08% except in Utah which has just lowered their limit to .05%. For THC, the primary intoxicant in marijuana, some states have adopted the limit of 5 nanograms per microliter (a millionth of a liter) of blood as a standard for the time being but this standard is controversial. Impairment due to marijuana use is a complex issue that goes far beyond a single measurement of how much THC is in the blood at a given moment.

As for other drugs, every state has laws that allow law enforcement personnel to charge a driver with Driving Under the Influence of Drugs but the laws vary widely. If you are interested in learning more about these state-by-state laws, please visit

An impaired driver’s view of the road

One fact is well established, however: A driver who mixes alcohol and marijuana greatly increases his (or her) chance of an accident. One study noted, “Marijuana and alcohol, when used together, have additive or even multiplicative effects on impairment.”

It’s difficult to determine the impairment of a marijuana-using driver who does NOT die in the crash, because THC is metabolized by the body so quickly. A test an hour or two later can have very different results than a test done at the time of the crash would.

How Impaired Were These Drivers?

The answer to this question can’t be fully answered at this point because of the shortage of conclusive research. It’s unfortunate that marijuana has been so broadly legalized for medical or recreational use without a standard of impairment being developed. In effect, our study group to determine impairment is everyone in the United States, with particular focus on the states with legal marijuana.

At the same time, there’s an increasing number of news reports on individuals overdosing on opioids in their vehicles, sometimes while they are driving or with children in the car. There’s no shortage of laws that would allow law enforcement to charge these drivers with failing to properly control their vehicles. Child endangerment laws also come into play when kids are present.

The fact remains that no driver is at their best when impaired by any level of alcohol, medication or illicitly-used drugs. Without standards we can use to warn the drug-using population of legal limits or provide to law enforcement to make it easier to take impaired drivers off the road, we may live through several years of experimentation in real life. The downside of this experimentation is, of course, that some people are likely to be hurt or even killed while we develop these standards.


Karen Hadley

For more than a decade, Karen has been researching and writing about drug trafficking, drug abuse, addiction and recovery. She has also studied and written about policy issues related to drug treatment.