Stoned driving again comes up WAY safer than drunk driving

A large meta-study has shown the dangers of driving while on cannabis are negligible compared to even threshold alcohol blood concentrations.  This once more shows the extreme injustice – and pointlessness – of roadside drug testing which measures only the presence of the drug, not impairment. A positive swab results in arrest and instant loss of licence.

"Canadian researchers analyzed data from 57 studies assessing the influence of cannabis and alcohol on driving behavior and crash risk. 

They acknowledged that cannabis exposure was typically associated with deviation in drivers’ lateral positioning (lane weaving) and a decrease in their average speed. Cannabis use was “not associated with an increase in crashes in experimental studies.” Authors also found “no compelling evidence” that cannabis influenced hazard response time, headway variability, time out of lane, speed variability, speed exceedance, or time speeding. 

They concluded, “Specifically, for the measures reported here, there are no instances where the average effect of cannabis is equal to or greater than the driving performance decrements associated with BAC concentration ranging from 0.04 to 0.06 percent.”