Canadian Underwriter

Marijuana driving deaths: the new highway scourge?

December 4, 2017   by Canadian Underwriter

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Marijuana is trending to be an even bigger killer on the roads than alcohol, according to stats on fatal driving accidents between 2000 and 2014.

“What we see is an increasing percentage of fatally injured drivers in Canada who tested positive for marijuana in recent years, whereas the percentage who tested positive for alcohol is decreasing,” explains Dr. Heather Woods-Fry, a research associate with the Traffic Injury Research Foundation (TIRF). “While the percent is still higher for alcohol today, if current trends continue, marijuana might become more prevalent among fatally injured drivers.”

According to TIRF’s National Fatality Database, in 2000, almost 35% of fatally injured drivers tested positive for alcohol compared to 12% who tested positive for marijuana,” TIRF noted in a release. “By 2014, this percentage for alcohol had declined to 28%, whereas it increased to almost 19% for marijuana.

The results were posted Monday by TIRF. Results are based on data from TIRF’s National Fatality Database, which is maintained with financial support from State Farm and the Public Health Agency of Canada.

Results vary greatly by age, the study found. Marijuana was the drug most commonly detected among fatally injured drivers aged 16-19 (29.8%) and between 20 and 34 years old (27.2%).

Fatally injured drivers in older age categories were more likely to test positive for other drug types, notably Central Nervous System (CNS) depressants (18.1% among drivers aged 35-64, and 26.3% among drivers 65 and older).

The time of day, and the day of the week, play a lesser role in predicting the presence of marijuana among fatally injured drivers compared to alcohol.

“Twenty one percent of drivers dying in weekend crashes tested positive for marijuana versus 17% in weekday crashes,” explains Robyn Robertson, president and CEO of TIRF. “In comparison, 46% of fatally injured drivers in weekend crashes tested positive for alcohol versus 26% in weekday crashes.”

Similar patterns are evident for time of day, with a more pronounced contrast in the presence of alcohol at night versus daytime and a less pronounced contrast in the presence of marijuana.

“Increased public education is essential to bringing awareness to the issue of cannabis and prescription drug impaired driving, with the impending legalization of recreational marijuana,” said John Bordignon, media relations spokesperson for State Farm Canada. “A resource like the DIDLC is a valuable tool that can help save lives.”

The DIDLC is the Drug Impaired Driving Learning Centre.

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3 Comments » for Marijuana driving deaths: the new highway scourge?
  1. Rafik Z says:

    Correlation is not causation. I don’t want us to make the mistake of interpretation of risk for this as we have made with alcohol. This time, in the opposite direction. Alcohol we presumed little risk until we saw the real risk in its effect. We should not jump the gun and presume ultimate risk with marijuana, when study after study indicates otherwise.

    Testing positive for the substance does NOT mean the person was so intoxicated that the intoxication is what caused the accident. It means that the substance was found in the body, period.

    I am not advocating for the use of marijuana when driving. I strongly condemn it as it is fundamentally irresponsible. Nonetheless, I am advocating that we don’t have the same delirious fervor of presumption that we had about the substance to initiate it’s illegality.

    Here is an excellent link to provide further insight;

    “…a large case-control study conducted by the National Highway Traffic Safety Administration found no significant increased crash risk attributable to cannabis after controlling for drivers’ age, gender, race, and presence of alcohol.” [Here is the study they meta-analysis they are referring to; Compton RP, Berning A. Drug and Alcohol Crash Risk. Washington, DC: National Highway Traffic Safety Administration; 2015. DOT HA 812 117.]

    Here is another study indicating otherwise;

    “…Because of both this and an increased awareness that they are impaired, marijuana smokers tend to compensate effectively while driving by utilizing a variety of behavioral strategies. Combining marijuana with alcohol eliminates the ability to use such strategies effectively, however, and results in impairment even at doses which would be insignificant were they of either drug alone. Epidemiological studies have been inconclusive regarding whether cannabis use causes an increased risk of accidents; in contrast, unanimity exists that alcohol use increases crash risk….”

    Let’s not be the rash ignoramuses we once were. Let’s act like we’ve actually learned something from our past behaviors.

    • Thank you for your thoughtful response.
      It is appropriate to advise the readers that the report you cite from NHTSA was done in a primarily military community in West Virginia and the involvement was on a volunteer basis.
      Regarding correcting for race, gender and age. This is a sound statistical practice but readers need to know that the entirety of data show marijuana as being statistically dangerous. Once the data was corrected for gender; ie removing all males from the analysis–marijuana was still unsafe. The data were further analyzed by correcting for age–removing all those under the age of 25 years old–marijuana WAS STILL UNSAFE. BUT once finally corrected for gender, age and race– by removing all races other than Caucasian, finally marijuana could be considered safe. So if it is an elderly, white woman smoking a joint….marijuana might be considered safe relative to alcohol or benzodiazepines.
      A good research/data analysis: page 49
      A driver in a fatal crash testing positive for only active THC (indicative of use within hours, not night before, not day before, not week before) and no other drugs or alcohol, is FIVE times more likely to kill someone other than themselves compared to a driver positive for only alcohol.
      Those driving under the influence of marijuana kill others.

  2. Taylor I says:

    The DIDLC is a State Farm entity, the article fails to mention this and leaves the impression that this is some sort of independent organization that does credible studies on the issue.
    I don’t recall the last time the media reported on any vehicle accident or death due to cannabis impairment probably because they never have. This is just a bit of propaganda in order to make an excuse to raise the insurance rates.
    What exactly measures cannabis impairment,how is it measured, what determines impairment,THC levels of how much is allowed and according to whom?

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