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NHTSA Study Results: Less Drunk Driving, More Drugged Driving

Posted By Regan Zambri Long, PLLC || 13-Jun-2016

Picture of Salvatore J. Zambri
Posted by Salvatore J, Zambri, founding member and partner.

Recent NHTSA studies results indicate that impaired driving enforcement now faces new challenges. Although the statistics reveal that drunk driving incidence has decreased, as more states legalize marijuana use, more drivers involved in crashes are testing positive for THC. Since 2007, the number of drivers testing positive for alcohol has decreased by nearly one-third. However, the same study showed a drastic increase in the number of drivers using marijuana or illegal drugs. The 2014 study showed nearly one in four drivers tested positive for drugs.

The NHTSA Roadside Survey of Alcohol and Drug Use by Drivers is a voluntary and anonymous survey that has been conducted five times over the past forty years. The most recent testing indicated a 30% decrease in alcohol prevalence among drivers since 2007 and an 80% decrease since the first survey in 1973. But, the surveys also revealed a large increase of drivers with drugs in their system in 2014, particularly during weekends. According to the NHTSA summary, "Changes in State policy on marijuana use, including medical and recreational use, may have contributed to an increase in marijuana use by drivers. However, the survey does not permit a state-by-state comparison. The change in use may reflect the emergence of a new trend in the country that warrants monitoring."

The second and more difficult-to-analyze study by the NHTSA attempted to determine whether marijuana use by drivers correlated to an increase in the risk of accidents. This survey found that marijuana users are more likely to be involved in accidents. However, the group with the highest incidence of marijuana use was also the group that is already considered higher risk, young men, leading research experts and law enforcement agencies unable to draw definitive conclusions.

The real challenges are in determining whether marijuana or other drug use results in impaired driving. Unlike alcohol use, which is known to be predictable and has a strong correlation between alcohol concentration and crash risk, several factors complicate the ability to make predictions for drug use:

  • "The large number of different drugs that would need to be tested;
  • Poor correlation between the effects on psychomotor, behavioral, and/or executive functions and blood or plasma drug concentrations;
  • Sensitivity and tolerance;
  • Individual differences in absorption, distribution, action, and metabolism;
  • Accumulation;
  • Acute versus chronic administration."

The NHTSA concludes that it is not possible currently to equate specific drug concentration levels to impaired driving. The associate administrator for research and program development for the NHTSA said, "Drivers should never get behind the wheel impaired, and we know that marijuana impairs judgment, reaction times and awareness. These findings highlight the importance of research to better understand how marijuana use affects drivers so states and communities can craft the best safety policies."

About the author:

Mr. Zambri is a board-certified civil trial attorney by the National Board of Trial Advocates and a Past-President of the Trial Lawyers Association of Metropolitan Washington, D.C. The association recently named him "Trial Lawyer of the Year". Super Lawyers recently named him among the "Top Ten" lawyers in the Metro Area (out of more than 80,000 attorneys). He has been rated by Washingtonian magazine as a "Big Gun" and among the "top 100″ lawyers in the entire metropolitan area. The magazine also describes him as "one of Washington's best-most honest and effective lawyers" who specializes in personal injury matters, including automobile accident claims, premises liability, product liability, medical malpractice, and work-accident claims. He has successfully litigated multiple cases against truck and bus companies, the Washington Metropolitan Area transit Authority, and other automobile owners. His law firm, in fact, has obtained the largest settlement ever in a personal injury case involving WMATA. Mr. Zambri has also been acknowledged as one of "The Best Lawyers in America" by Best Lawyers (2014 edition) and has been repeatedly named a "Super Lawyer" by Super Lawyer magazine (2014) - national publications that honor the top lawyers in America.

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