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The number of drivers with cannabis, opioids in system is rising

On behalf of Dolan + Zimmerman LLP June 29, 2018

A recent report by the Governors Highway Safety Association indicates that we are seeing a lot more drugged driving. That may not come as a surprise, as the use of both cannabis and opioids has been on the rise. What should law enforcement and policy groups do?

The researchers used data from the National Highway Traffic Safety Administration (NHTSA). Researchers reviewed both roadside surveys and NHTSA’s Fatality Analysis Reporting System (FARS). FARS is essentially a database of local police reports taken after fatal traffic crashes. These data sources were chosen as reliable and nationally representative, although the researchers acknowledge that no source of data accurately documents all driver drug testing.

Data was examined involving drivers who had been killed in traffic wrecks in 2016. Of those drivers who were tested for drugs, nearly 44 percent tested positive — up from only 28 percent in 2006.

Among those who did test positive, 38 percent tested positive for cannabis. Another 16 percent tested positive for opioids. Four percent tested positive for both cannabis and opioids. Overall, 51 percent came up positive for two or more drugs.

These results highlight the complexity of dealing with driver substance abuse. It’s no longer a matter of some people using alcohol and others using drugs, according to the head of, which funded the study. We need to understand that drivers may use multiple substances — some legal, some legally prescribed, and some illegal.

Adding to the complexity is the fact that the mere presence of a drug in someone’s system does not always indicate impairment. For example, people who smoke marijuana are thought to be impaired for two hours or so after consumption. Once the “high” passes, however, they will still test positive for the drug but may no longer be impaired depending on their body fat percentage, habits of use, and other factors.

With prescription drugs, the person may have an active dose in their system but not be impaired at all. That points out another problem for policymakers: The effects of drugs can vary by substance, dose, timing and the individual characteristics of the person using them.

Furthermore, there are many drugs to test for, each of which has different effects. And, there is no scientifically accepted method of testing for impairment itself as opposed to the presence of the drug.

It’s a complex issue. Drivers do need to understand that most drugs, including marijuana and many prescription drugs and opioids, can impair driving ability. Unfortunately, according to these researchers some people falsely believe that marijuana or opioids will not impair their driving ability.

If you use marijuana, opioids or other prescription drugs, it is important to realize that even legal drugs that you are prescribed for legitimate medical reasons can, and often do, cause impairment.