:bouncetau
"Experts at Dalhousie University"?.
the Nixon Marijuana Commission concluded that there is no conclusive evidence that cannabis impairs driving. This was in part based on studies by Crancer et.al. for the Washington State Highway Department, a similar study done at UCLA, and another at Boston University. Crancer found that, "Simulated driving scores for subjects experiencing a normal social 'high' and the same subjects under control conditions are not significantly different
A 1983 study by the US National Highway Transportation Safety Administration (NHTSA) concluded that the only significant affect of cannabis use was slower driving - arguably a positive effect of driving high.
A comprehensive 1992 NHTSA study revealed that pot is rarely involved in driving accidents, except when combined with alcohol. The study concluded that "the THC-only drivers had an [accident] responsibility rate below that of the drug free drivers." This study was buried for six years and not released until 1998
A massive 1998 study by the University of Adelaide and Transport South Australia examined blood samples from drivers involved in 2,500 accidents. It found that drivers with only cannabis in their systems were slightly less likely to cause accidents than those without. Drivers with both marijuana and alcohol did have a high accident responsibility rate. The report concluded, "there was no indication that marijuana by itself was a cause of fatal accidents
In Canada, a 1999 University of Toronto meta-analysis of studies into pot and driving showed that drivers who consumed a moderate amount of pot typically refrained from passing cars and drove at a more consistent speed. The analysis also confirmed that marijuana taken alone does not increase a driver's risk of causing an accident.