Notes for Marijuana and Driving
[1a] "The largest study ever done linking road accidents with drugs and alcohol has found drivers with cannabis in their blood were no more at risk than those who were drug-free.
[The study of 2500 accidents] by a pharmacology team from the University of Adelaide and Transport SA showed drivers who had smoked marijuana were marginally less likely to have an accident than those who were drug-free.
'Essentially it is the same as if there was no drug,' study spokesman, Dr. Jason White said.
"Dr. White said the study showed the importance of concentrating efforts on alcohol rather than other drugs."
- The Age (Australia) 21 Oct 1998
[1b] "Last year, a researcher at the University of Toronto reviewed a dozen studies, and concluded that marijuana is nowhere near as likely to impair a driver as alcohol is. For one thing, the drugs have opposite effects:
Alcohol causes drivers to speed up and drive recklessly, but marijuana causes drivers to slow down and take more care.
Even more surprising, perhaps, are the results of two studies that showed, through analysis of accident statistics, that marijuana users are no more likely to cause an accident than sober drivers. This suggests marijuana may not be a problem on the road, and certainly nowhere near as dangerous a problem as alcohol."
- Ottawa Citizen (Canada) Editorial: 14 Jan 2003
[1c] "The March 19th issue of New Scientist reports that a single glass of wine impairs driving more than smoking a joint.
"The study was conducted by (Britain's) Transport Research Laboratory and confirms the results of previous studies. Marijuana affected just one test category, the ability of drivers to follow the middle of the road at constant speed when driving a figure-eight loop. Drivers who drank the equivalent of a glass of wine fared much worse at the task than those who had smoked an entire joint.
"Of particular interest is the finding that marijuana test subjects tended to be cognizant of their intoxication and drove cautiously as a result."
- The Age (Australia) 21 Mar 2002
[1d] "Rob Tunbridge, head of impairment studies at [Britain's] transport research laboratory, said: 'All of the tests that have been done in other countries suggest that cannabis has a completely different effect to alcohol. Rather than giving you dutch courage and confidence, it actually makes you much more cautious in your approach to driving.' "
- The Guardian (UK)27 Jan 2000
[1e] "The Canadian Senate report concluded, 'Cannabis alone, particularly in low doses, has little effect on the skills involved in automobile driving.'
In head to head match-ups versus non-users, cannabis users performed better in eight out of ten match-ups. [On a driving simulator test.] However, when the dosage was increased to the equivalent of two marijuana cigarettes, non-users won the majority of one-on-one contests." [It would be unlikely for even a heavy marijuana smoker to be under the influence of two joints.]
- Britain's Evening News, 2-2-04
[2] - Dr. Andrew Weil, "What No One Wants to Know About Marijuana", in The Natural Mind