Mythbusters: Cannabis does not affect driving
I can’t agree with you more about the increased risk for motor vehicle accidents and concurrent cannabis use. Statistics support this increased risk. The New England Journal in 2014 reported, “In an accident culpability analysis, persons testing positive for THC (typical minimum level of detection, 1 ng per milli- liter), and particularly those with higher blood levels, were 3 to 7 times as likely to be responsible for a motor vehicle accident as persons who had not used drugs or alcohol before driving.” Unfortunately, these statistics may be misleading because finding THC in the blood at such low levels does not correlate with acute intoxication. Until we get a field deployable sobriety analyzer, we will not know the true impact of cannabis use on driving impairment.
Ramaekers JG, Berghaus G, van Laar M, Drummer OH. Dose related risk of motor vehicle crashes after cannabis use. Drug Alcohol Depend 2004;73:109-19.