Marijuana Not A Factor In Driving Accidents

March 30, 1999

The safety hazards of smoking marijuana and driving are overrated, says University of Toronto researcher Alison Smiley.

Recent research into impairment and traffic accident reports from several countries shows that marijuana taken alone in moderate amounts does not significantly increase a driver's risk of causing an accident -- unlike alcohol, says Smiley, an adjunct professor in the department of mechanical and industrial engineering. While smoking marijuana does impair driving ability, it does not share alcohol's effect on judgment. Drivers on marijuana remain aware of their impairment, prompting them to slow down and drive more cautiously to compensate, she says.

"Both substances impair performance," Smiley says. "However, the more cautious behaviour of subjects who received marijuana decreases the drug's impact on performance. Their behaviour is more appropriate to their impairment, whereas subjects who received alcohol tend to drive in a more risky manner."

Smiley, who has studied transportation safety for over 25 years, drew her results from a "metanalysis" of existing research into the effects of marijuana on driving ability, combined with traffic accident statistics in the United States and Australia. Previous studies showing stronger effects often combined "fairly hefty doses" by researchers with driving immediately after consumption, likely exaggerating the drug's effects, she believes.

While Smiley does not advocate legalizing the drug, she says her results should be considered by those debating mandatory drug tests for users of transportation equipment such as truck or train drivers, or the decriminalization of marijuana for medical use. "There's an assumption that because marijuana is illegal, it must increase the risk of an accident. We should try to just stick to the facts."

Smiley presented her findings at a symposium of the American Academy of Forensic Sciences in Florida in February. Her paper was also published in Health Effects of Cannabis, a publication of Toronto's Centre for Addiction and Mental Health, in March.
-end-
CONTACT: Professor Alison Smiley, department of mechanical and industrial engineering
416-596-1252
smiley@ecf.utoronto.ca

Bruce Rolston, U of T public affairs
416-978-6974
bruce.rolstone@utorionto.ca

University of Toronto

Related Addiction Articles from Brightsurf:

Opioid addiction treatment is more widely available, but only for adults
Primary care providers have expanded access to buprenorphine for adults, but use of the opioid addiction treatment has decreased among the youngest patients, find researchers at Columbia University.

Is video game addiction real?
A recent six-year study, the longest study ever done on video game addiction, found that about 90% of gamers do not play in a way that is harmful or causes negative long-term consequences.

Eating disorders linked to exercise addiction
New research shows that exercise addiction is nearly four times more common amongst people with an eating disorder.

Co-addiction of meth and opioids hinders treatment
A study published in the Journal of Substance Abuse Treatment found that methamphetamine use was associated with more than twice the risk for dropping out of treatment for opioid-use disorder.

New tool to assess digital addiction in children
A new study developed and validated a tool for assessing children's overall addiction to digital devices.

Addiction intervention in hospital is a 'reachable moment'
Patients who meet an addiction medicine consult team while they're in the hospital are twice as likely to participate in treatment for substance use disorder after they go home, according to new research.

How stress leads to Facebook addiction
Friends on social media such as Facebook can be a great source of comfort during periods of stress.

Systematic review of food addiction as measured with the Yale Food Addiction Scale
The aim of this paper was to review the clinical significance of food addiction diagnoses made with the Yale Food Addiction Scale (YFAS) and to discuss the results in light of the current debate on behavioral addictions.

Drugs of abuse: Identifying the addiction circuit
What happens in the brain of a compulsive drug user?

Pancreatic cancer's addiction could be its end
Researchers at CSHL have discovered that an inappropriately produced protein may be why some pancreatic cancer patients die exceptionally early.

Read More: Addiction News and Addiction Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.