RESEARCH - Blood THC Concentration and Driver Impairment

The American Automobile Association Foundation for Traffic Safety has released a report titled An Evaluation of Data from Drivers Arrested for Driving Under the Influence in Relation to Per se Limits for Cannabis. Researchers examined Drug Recognition Expert (DRE) and impaired driving arrest investigation data and compared the blood levels of THC to observed impairment. The conclusion made was that a quantitative threshold for per se laws for THC following cannabis use cannot be scientifically supported.

Link:

• Read An Evaluation of Data from Drivers Arrested for Driving Under the Influence in Relation to Per se Limits for Cannabis
• Report on Drug Per Se Limits - Canadian Society of Forensic SciencesDrugs and Driving Committee