Associate Professor Mark Asbridge of Dalhousie University has led a study using data reflecting how smoking marijuana in the hours before you drive can still impair your driving ability.
The Canadian research team finds that smoking marijuana up to three hours before driving can almost double the chances of the driver being involved in an accident.
“To our knowledge this meta-analysis is the first to examine the association between acute cannabis use and the risk of motor vehicle collisions in real life,” the researchers write in the latest issue of the British Medical Journal.
A total of 49,411 accident victims along with nine observational studies were picked through to find the ones where only marijuana was proven to be used either in a blood test or from driver reports. While it does appear to double the risk, the researches have yet to determine the level of intoxication that poses this risk.
“Although we did not examine dose effects on the risk and severity of collisions, studies of fatally injured drivers found higher amounts of tetrahyrocannabinol in the blood,” they write, adding that this either indicates heavier consumption of THC or shorter timeframe between consumption and testing.
Prior studies conducted have indicated that cannabis had a negative impact on motor skills that enable drivers to do so safely, and that while it is more likely that the drug is associated with minor incidents, so far there is no research to prove that.
– By: Alexandra Koken