1. Headline
  1. Headline
updated 2/10/2012 12:56:51 PM ET 2012-02-10T17:56:51

People who use marijuana before driving are nearly twice as likely to cause a car crash as those not under the influence of alcohol or drugs, according to a Canadian analysis of previous studies.

  1. More from TODAY.com
    1. Buying running shoes? Here’s what to expect

      Whether you are thinking about signing up for your first 5K or are gearing up for a full marathon, the first two steps in ...

    2. 'Sex Box': Couples therapy or reality show trash?
    3. Food-themed hotels are popping up around the world
    4. Catch up on all the news of the week with ‘The Download’
    5. Missing Oscar dress worn by Lupita Nyong’o may be found

Experts at Dalhousie University in Canada reviewed nine studies of more than 49,000 people involved in accidents on public roads involving one or more motor vehicles, including cars, trucks, buses and motorcycles. Marijuana use was confirmed by blood tests or self-reporting.

Researchers found drivers who had used marijuana within three hours of beginning to drive had nearly double the risk of causing a collision, especially those that were fatal.

Marijuana is the most widely used illegal drug worldwide and rates of its use in drivers are increasing. A 2007 study in Scotland found 15 percent of 537 drivers aged 17 to 39 had used marijuana within 12 hours.

Some experts said education campaigns about the dangers of doing drugs before driving wouldn't work.

People "will also need to be persuaded that they are at risk of their cannabis use being detected," wrote Wayne Hall of the University of Queensland in an accompanying editorial.

Hall said more research was needed to prove whether roadside drug testing, as introduced in parts of Australia and the U.S., actually prevents more drug-related car accidents.

The study was published Friday in the journal, BMJ.

Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Discuss:

Discussion comments

,

Most active discussions

  1. votes comments
  2. votes comments
  3. votes comments
  4. votes comments

More on TODAY.com

  1. Shutterstock

    Buying running shoes? Here’s what to expect

    2/28/2015 12:52:17 PM +00:00 2015-02-28T12:52:17
  1. TODAY

    'Sex Box': Couples therapy or reality show trash?

    2/28/2015 2:57:40 PM +00:00 2015-02-28T14:57:40
  1. Unique Vision Photography

    Since groom's moving vows to stepdaughter, this blended family's grown

    2/27/2015 10:04:41 PM +00:00 2015-02-27T22:04:41
  1. TODAY

    video Catch up on all the news of the week with ‘The Download’

    2/28/2015 12:58:44 PM +00:00 2015-02-28T12:58:44
  1. TODAY

    video Jeb Bush tries to make the case for 2016 to conservatives at CPAC

    2/28/2015 12:30:14 PM +00:00 2015-02-28T12:30:14