The NHTSA has released the results of what it is billing as the most precisely controlled study of its kind on the association between smoking marijuana and fatal highway crashes. It is also the largest study of its kind ever conducted.
The findings are very interesting.
Despite the fact that there is a large percentage of drivers were involved in crashes who took illegal drugs (marijuana was not specifically screened out), there is no apparent connection solely between marijuana use and highway accidents.
That said, almost 50% of drivers appeared to have marijuana metabolites in their system. This is far from being impaired due to the drug.
The uncertainties about marijuana use and driving are also why new laws about drugged driving particularly when it comes to marijuana, are so contentious. Drivers who are not functionally impaired can still test positive for the drug 30 days after ingestion. Medical users therefore, have a level of metabolite in their systems from regular use that puts them in the “impaired” category without necessarily being so.
What does appear to be apparent however, is that a number of “risk factors” for being involved in accidents do tend to cluster with accidents overwhelmingly, including being young and male. Marijuana use, however, can not, and certainly at this juncture, be blamed for an automatic association of greater driving risk, per the new findings of the NHTSA.
It is still too early to tell if this study will impact the spread of drugged driving laws across the US.
The study also found that the number of Americans who were intoxicated behind the wheel continues to fall after decades long campaigns to halt the practice. In fact, between 2007, the number of drivers with alcohol in their system who have been involved in fatal or serious driving accidents has dropped sharply (nearly 30%). It has dropped by nearly 75% since 1973.
The National Roadside Survey has been conducted five times over the last 40 years. It is also voluntary. Drivers are alerted that a voluntary survey site is ahead and are invited to participate.