Commentary: Concern about drugged driving shouldn’t derail cannabis bill


By Paul Armentano

Concerns expressed by AAA regarding pending legislation to regulate the adult-use cannabis market in Delaware are understandable (“Legalization of cannabis leads to more traffic fatalities,” March 29). No one, including advocates for this measure, wishes to negatively impact traffic safety. Fortunately, the real-world experience with regulating cannabis for both medical purposes and for recreational use indicates that legalization can be enacted in a manner that is both safe and effective.

First, it should be stressed that driving under the influence of marijuana is already a criminal offense in Delaware. Nothing in the language of the proposed law changes this reality.

Secondly, scientific studies find that marijuana-positive drivers possess a low accident risk, particularly when compared with alcohol-positive drivers. The largest controlled trial assessing marijuana use and motor vehicle accidents, published in 2015 by the National Highway Traffic Safety Administration (NHTSA), reports that marijuana-positive drivers possess virtually no statistically significant crash risk (adjusted odds ratio: 1.05) compared to drug-free drivers after controlling for age and gender. By contrast, drivers with detectable levels of alcohol in their blood at legal limits possess nearly a fourfold risk of accident (odds ratio: 3.93), even after adjusting for age and gender.

Further, data to date from states that have liberalized marijuana’s legal status generally show little or no uptick in motor vehicle crashes. Specifically, The University of Texas researchers, writing in the August 2017 edition of The American Journal of Public Health, compared traffic-crash data in the three years prior to the enactment of adult-use legalization in Colorado and Washington versus data trends in the three years following legalization. “We found no significant association between recreational marijuana legalization in Washington and Colorado and subsequent changes in motor vehicle crash fatality rates in the first three years after recreational marijuana legalization,” they concluded.

A separate assessment authored by researchers at the University of Oregon, titled “Early Evidence on Recreational Marijuana Legalization and Traffic Fatalities,” reached a similar conclusion. They, too, compared traffic-safety trends in Colorado and Washington post-legalization versus similar states that did not amend their cannabis laws. They concluded: “We find that states that legalized marijuana have not experienced significantly different rates of marijuana- or alcohol-related traffic fatalities relative to their synthetic controls.”

A study of California data, published in 2018, concluded, that legalizing medical marijuana in California led to a sustained reduction in statewide motor vehicle fatalities. An assessment of traffic-safety data from Washington and Oregon, published in 2020, reported: “We found no significant differences in pedestrian-involved fatal motor vehicle crashes between legalized cannabis states and control states following medical or recreational cannabis legalization.”

A study published this year in The American Surgeon journal assessed motor vehicle crash data collected over 12-years at trauma centers in legal and nonlegal states (Arizona, California, Ohio, Oregon, New Jersey and Texas). Authors concluded, “There did not appear to be a relationship between the legalization of marijuana and the likelihood of finding THC in patients admitted after MVC (a motor vehicle crash). … There was no apparent increase in the incidence of driving under the influence of marijuana after legalization.”

Nevertheless, AAA is correct that use of marijuana prior to driving ought to be discouraged and that greater efforts ought to be made to provide police with adequate tools to identify drivers who may be under its influence. These include greater funding for the training of drug-recognition evaluators (DREs) and the use of modified roadside field sobriety tests.

These efforts should not include the imposition of “per se” thresholds for THC or its metabolites, as such limits are not scientifically correlated with driver impairment. As acknowledged by AAA, which similarly opposes such thresholds, “There is no evidence from the data collected … that any objective threshold exists that established impairment, based on THC concentrations.”

Efforts should also be made to better educate the public with regard to the existing traffic-safety laws, as well as to the evidence surrounding marijuana’s potential influence on driving. In particular, this messaging should stress that combining marijuana and alcohol greatly impacts driving behavior and is associated with far greater risk of accident than the use of either substance alone.

In addition to increasing public safety, implementing these steps would help assuage concerns from AAA and others that further regulating the adult use of marijuana could potentially lead to an increase in incidences of drugged driving or limit the state’s ability to successfully identify and prosecute such behavior.

Paul Armentano is the deputy director of the National Organization for the Reform of Marijuana Laws (NORML) and the author of several peer-reviewed papers on the subject of cannabis, psychomotor performance and accident risk.