Study: Today’s Drugged Drivers More Likely to Mix Alcohol and Drugs, Have Taken Multiple Prescription Medicines

Jun 23, 2014, 1:16 PM

The profile of a drugged driver has changed substantially since 1993, according to a new study released today in the journal Public Health Reports, which shows that more drivers are now testing positive for prescription drugs, marijuana and multiple drugs.

“While we’ve seen a decrease over the years in motor vehicle fatalities involving people under the influence, the nature of those crashes is changing,” said study author Fernando Wilson, PhD, an associate professor at the University of Nebraska Medical Center.

The study examines trends in the characteristics of U.S. drivers who were involved in fatal crashes between 1993 and 2010 and tested positive for drugs. The study, funded by the Public Health Law Research program of the Robert Wood Johnson Foundation, was set up to investigate the relationship between state laws and the consumption of alcohol and other drugs in fatal car crashes. It found that the percentage of drugged drivers with three or more drugs in their system nearly doubled from 1993 to 2010, increasing from 11.5 percent to 21.5 percent. 


“In 1993, about one in eight drivers were using multiple drugs concurrently. By 2010, it was closer to one in five. That’s a large increase in drug use,” Wilson said. “Beyond that, we’re also seeing more and more people using drugs and alcohol together. About 70 percent of drivers who tested positive for cocaine had also been consuming alcohol, and almost 55 percent of drivers who tested positive for cannabis also had alcohol in their systems.”

Additional findings:

  • Almost 60 percent of cannabis-only users were younger than 30 years.
  • Thirty-nine percent of prescription drug users were 50 years old or older, which seems to be in line with an overall increase in the use of prescription drugs by Americans, and the older population in general.

“These trends are likely to continue into the future given the aging U.S. population, an increasing reliance on prescription medications by medical providers and increasing initiatives to legalize marijuana,” said Wilson. “However, it is unclear whether current state policies are completely up to the challenge of addressing the growing issue of drugged driving.”

NewPublicHealth recently spoke with Wilson about the study. He said he embarked on the research because of the tens of thousands of motor vehicle crashes each year and the need to figure out the most effective policies to curb distracted driving. According to Wilson, eighteen states have zero-tolerance laws for drugged drivers, but recent studies suggest that these laws may not be effective enough in decreasing traffic deaths.

NewPublicHealth: Tell us about the new study.

Fernando Wilson: We have a database called the Fatality Analysis Reporting System (FARS), which compiles data on every fatal crash that occurs on public roads in the United States, and we use that data to look at trends and the drivers involved in the crash to see if they had detectable drugs in their system. The reporting system includes test results for those drivers and we looked at whether over time—between 1993 and 2010—there were any changes in the profile of these drugged drivers involved in fatal crashes in the United States.

NPH: What did you find?


Wilson: We found a few things. One, that in recent years, since the mid-2000s, prescription drug use has become more and more prevalent among drivers involved in fatal crashes. In fact, it’s surpassed cannabis. For many years, cannabis use was the most commonly detected drug among drug drivers, but now its prescription drug use. We also found that whereas cannabis is predominately dominated by younger drivers, drivers who are age 50 and above account largely for the prescription drug users. We link that to the fact that we have an aging population. The number of prescriptions being filled has risen dramatically since the ‘90s, particularly for older adults.

We also found a lot of mixing across different types of both illicit and prescribed drugs, though the reporting system does not tell us whether the drugs, [such as Oxycontin, a narcotic often taken without a prescription by borrowing, stealing or buying the drug without a prescription] were legally prescribed. About the only thing we know is that they were involved in a fatal crash and the drug was detected in their bloodstream, but we don’t know whether they themselves were legally prescribed that drug or not.

Multiple drug use has certainly increased among the driver data we studied. In the early ‘90s, one in eight drug drivers use three or more drugs. Now, it’s more than one in found drivers who have at least three drugs detected in their bloodstream.

NPH: How would you say the profile of a drugged driver has changed in the last few years?

Wilson: We see that cocaine and methamphetamine are becoming less and less prevalent. Drugged drivers now would be much more likely to be using marijuana and prescription drugs, and they would probably be more likely to be mixing those drugs with alcohol. We see that overall fatalities are going down, perhaps because people are more likely to be in seat belts, but the mixing of alcohol with drugs is not trending down. It’s becoming more of a problem.

NPH: What changes in society are changing what is likely to be in a drugged driver’s system?

Wilson: A strong possibility is the aging demographic profile of the population. We have more and more prescription drugs being taken to treat complex diseases such as diabetes, where you have a greater reliance on a mix of drugs—and we anticipate that’s going to continue. With respect to cannabis—or marijuana—legalization is increasing and we don’t anticipate that’s going to reverse in the future. Our results suggest that policymakers, even in states that have liberalized cannabis use, should think about designing policies that might curb the use of cannabis while driving, such as increased penalties.

NPH: Why don’t zero-tolerance laws have a greater impact on reducing deaths?

Wilson: So far it’s unclear. Part of the problem might be that the design of these laws varies fairly substantially across states. So, some states will have mandatory imprisonment for a first offense. Other states don’t, so even if they have a drug law, the penalties, the enforcements and the prosecution might vary substantially.

NPH: What should be done—both from a legal standpoint from a public health standpoint—on this issue?

Wilson: Well, I think certainly we need greater recognition of this issue in the medical community. The provider should say “I’m prescribing this drug. Make sure you think about the fact that this drug may have side effects, which may impair your driving and you may want to make arrangements for transportation alternatives.” Though often there are no alternatives, which is another issue public health needs to be addressing—to look at the mass transit infrastructure. I think part of that discussion can be in terms of the numbers of people who must take multiple drugs that can impair their driving. In terms of marijuana, I think stricter penalties and more resources devoted to enforcement and prosecution might warrant examination. We also need to have further investigation in terms of how combinations of drugs affect driving ability, and how that affect is exacerbated when illicit drugs and alcohol are added into the mix.

>>Bonus Link: Learn more about prescription monitoring program laws at

This commentary originally appeared on the RWJF New Public Health blog.