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. 9 hilarious Halloween moments from KLG, Hoda as 'Wayne's World' hosts

      Today marked a new high (or low) for Kathie Lee and Hoda as they traded their Spanx and wine glasses for ripped jeans and ...

    2. See TODAY’s ' 'Saturday Night Live' Halloween costumes
    3. Cookies, bark and 5 other treats to make with your leftover Halloween candy
    4. These babies in Halloween costumes will brighten your day
    5. How to max your Halloween candy haul

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 This material may not be published, broadcast, rewritten or redistributed.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. Samantha Okazaki / TODAY

    Party on, TODAY! See ‘Saturday Night Live’ costumes for Halloween 2014

    10/31/2014 12:15:55 PM +00:00 2014-10-31T12:15:55
  1. Courtesy of Arti Ghole

    These babies in Halloween costumes will brighten your day

    10/31/2014 4:57:53 PM +00:00 2014-10-31T16:57:53
  1. Chinchilla/bauer-griffin / Getty Images

    Cheetos, Clooneys, Slash and more: Celebs get creative for Halloween

    10/31/2014 4:06:44 PM +00:00 2014-10-31T16:06:44
  1. Just a Taste; Glorious Treats; Baker by Nature

    Cookies, bark and 5 other treats to make with your leftover Halloween candy

    10/31/2014 4:08:19 PM +00:00 2014-10-31T16:08:19