A recent literature review published in the Journal of AOAC International has brought into question the validity of using THC detection in bodily fluids as a basis for determining behavioral impairment, particularly in the context of driving.
Researchers from the University of California at Davis conducted the review, affirming that the presence of THC or its metabolites in blood, breath, urine, or saliva is not indicative of impairment. This conclusion aligns with the stance of various traffic safety groups, including the National Highway Traffic Safety Administration and the American Automobile Association.
The study highlights the limitations of current methods that focus on THC concentrations in bodily fluids. It notes that these methods can yield false-positive results for recent cannabis use due to THC’s persistence in the body beyond the typical window of impairment following consumption.
Per se traffic safety laws, which criminalize drivers based on trace levels of THC in their blood, have been adopted in several states. However, the study’s authors argue that these laws are not scientifically supported and risk wrongly accusing drivers who are not impaired or who have not recently consumed cannabis.
States such as Illinois, Montana, Ohio, Pennsylvania, and Washington have implemented various per se THC limits, while others, including Arizona, Delaware, and Michigan, impose zero-tolerance standards. Under these laws, drivers with detectable THC levels in their blood can be penalized, even in the absence of evidence of impairment.
Organizations like NORML have long opposed per se THC limits for motorists and advocate for alternative approaches to address concerns over cannabis-related impaired driving. NORML’s deputy director, Paul Armentano, emphasizes that THC or its metabolites in bodily fluids are inconsistent indicators of impairment, particularly at low levels.
Armentano suggests that lawmakers consider alternative legislative approaches that do not solely rely on THC detection to determine guilt. He warns against the potential misuse of traffic safety laws to punish individuals engaged in legally protected behavior and who pose no actual threat to traffic safety.
The findings of this study underscore the complexities involved in translating analytics to determine recent cannabis use and impairment accurately. As policymakers grapple with addressing cannabis-related driving concerns, it is essential to prioritize evidence-based approaches that prioritize both public safety and individual rights.