Cannabis & impaired driving

Pin It

Updated September 9, 2021 Cannabis and impaired driving

We must all be responsible adults especially *law enforcement and other professionals in the media and health care fields and seriously look at and listen to the scientific evidence.

Cannabis keeps getting compared to the toxic (deadly) drug alcohol. Cannabis is not toxic. Cannabis and alcohol are just not the same. Under the influence, behaviors are not the same as alcohol or pharmaceutical drugs for the most part.

Daily medical cannabis consumers generally gain experience and build up a tolerance. Most adults would not be impaired if they took an aspirin for a headache. The same can be said for daily medical cannabis consumers when consuming small amounts over the course of a day.
This is not to say experienced medical cannabis consumers can't become impaired by consuming cannabis concentrates, edibles or larger quantities of flowers even.

Several years now pharmaceutical drug advertisements have included warnings about possible side affects that could cause impairment, statements like, know how our drug effects you before operating motor vehicles or equipment. In other words consumption does not automatically equal you're impaired.

Distracted driving and walking are impaired behaviours. Parents drive while distracted by their children. Pet owners drive while distracted by their pets. Using a cell phone. Lack of sleep, human emotions, stress, mental health and more are all part of the important impaired issue.

Education based on scientific evidence only without the typical proven reefer madness nonsense.

Be responsible and never drive whenever “impaired” from consuming any substance or distracted or for any other reasons!

*Irresponsible law enforcement and media professionals
See Dr. Susan C. Boyd, a B.C. researcher's book "Killer Weed: Marijuana Grow Ops, Media and Justice". about how law enforcement and media are not telling the facts.
Google Dr. Susan C. Boyd's "Reefer madness is governmental"
Note: Dr. Susan C. Boyd is a member of Liberal government "Task Force on Marijuana Legalization and Regulation"

Cannabis Driving Studies 2021 to 2002

August 27, 2021
Science Direct
Canada’s cannabis legalization and drivers’ traffic-injury presentations to emergency departments in Ontario and Alberta, 2015-2019

Conclusions: Implementation of the Cannabis Act was not associated with evidence of significant post-legalization changes in traffic-injury ED visits in Ontario or Alberta among all drivers or youth drivers, in particular.

February 5, 2021
Results from a simulated driving study.

Conclusions: There appears to be a poor and inconsistent relationship between magnitude of impairment and THC concentrations in biological samples, meaning that per se limits cannot reliably discriminate between impaired from unimpaired drivers. There is a pressing need to develop improved methods of detecting cannabis intoxication and impairment."

December 1, 2019
Impact on driving speed and lateral control

Conclusions: Acutely, cannabis caused decreased speed, increased heart rate, and increases in VAS drug effect and drug high. There was no evidence of residual effects on these measures over the two days following cannabis administration.

May 14, 2019
CRS Report: THC Levels Not Correlated With Driver Impairment
Summary @ crs-report thc-levels not correlated with driver impairment
Full report @ Congressional Research Service report driving May 2019.pdf

June 27, 2017
Canadians for Fair Access to Medical Marijuana (CFAMM)
Medical Cannabis and Impaired Driving: A Preliminary Report

June 22, 2017
Crash Fatality Rates After Recreational Marijuana Legalization in Washington and Colorado
American Journal of Public Health (ajph)
Objectives. To evaluate motor vehicle crash fatality rates in the first 2 states with recreational marijuana legalization and compare them with motor vehicle crash fatality rates in similar states without recreational marijuana legalization.

February 1, 2017
Cannabis Use and Driving: Knowledge Translation Strategy Recommendations In reviewing the evidence relating to cannabis impairment and driving, we have highlighted several main considerations with respect to context, tone, and audience when developing messaging for public education. This document outlines these considerations.

December 2016
US NHTSA Drugs & Alcohol Crash Risk Case Control Study
See 812355_DrugAlcoholCrashRisk.pdf
March 17, 2016 John W. Conroy QC wrote to Mr. Costen, Mr. Blair and Mr. Sidhu:

"I am attaching a most recent study on the issue of impaired driving by alcohol and drugs by the US National Health Transportation Safety Association(NHTSA)(The Virginia Beach Study) that, once again, supports the position that fears over impaired driving crash risk consequences from the greater consumption of cannabis by its “legalization” are misplaced and are no reason to further delay implementation of the proposed ‘legalization” scheme. The current laws in place are adequate while science and technology furthers its quest for a fair and effective roadside screening device or process."

June 3, 2016
Motor Mouth: Hysteria over ‘high driving’ is all half-baked Marijuana, by most measures, is not in any way the scourge that alcohol is

February 2015
National Highway Traffic Safety Administration finds that drivers who use marijuana are at a significantly lower risk for a crash than drivers who use alcohol.

August 5, 2014
Since marijuana legalization, highway fatalities in Colorado are at near-historic lows

May 2013
Medical Marijuana Laws, Traffic Fatalities, and Alcohol Consumption - Anderson, Hansen, and Rees
The first full year after coming into effect, legalization is associated with an 8–11 percent decrease in traffic fatalities

April 6, 2012
Marijuana Users Are Safer Drivers Than Non-Marijuana Users, New Study Shows

November 2011
Medical Marijuana Laws, Traffic Fatalities, and Alcohol Consumption
D. Mark Anderson University of Montana and Daniel Rees University of Colorado

16 states have passed medical marijuana laws, yet very little is known about their effects. Using state-level data, we examine the relationship between medical marijuana laws and a variety of outcomes. Legalization of medical marijuana is associated with increased use of marijuana among adults, but not among minors. In addition, legalization is associated with a nearly 9 percent decrease in traffic fatalities, most likely to due to its impact on alcohol consumption. Our estimates provide strong evidence that marijuana and alcohol are substitutes.

May 2010
The Effects of Cannabis Compared with Alcohol on Driving
PMC Journal: Authors - R. Andrew Sewell, MD,corresponding author James Poling, PhD, and Mehmet Sofuoglu, MD, PhD

Alcohol causes more impairment than cannabis and carries a demonstrably higher crash risk. Drivers under the influence of cannabis are acutely aware of their impairment. They consciously try to drive more cautiously, for example by slowing down, focusing their attention and avoiding risks. Drinking drivers show more risk taking and aggression in their driving, have no insight into their impairment, and do not try to compensate.

The psychoactive chemical in marijuana is tetrahydrocannabinol (THC). THC has a very different effect from alcohol. Pot users are acutely aware of their impairment - that is, they feel "high" - and some try to compensate by driving more cautiously.

Chapter: 8 Driving under the influence of cannabis

• Cannabis alone, particularly in low doses, has little effect on the skills involved in automobile driving.
• Cannabis, particularly in the doses that match typical doses for regular users, has a negative impact on decision time and trajectory.
• Cannabis leads to a more cautious style of driving.
• The effects of cannabis when combined with alcohol are more significant than for alcohol alone.

Cannabis & impaired driving -

International Centre for Science in Drug Policy -