Citation

Wood E. J. Glob. Drug Policy Pract. 2016; 10(3).

Copyright

(Copyright © 2016, Institute on Global Drug Policy)

DOI

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PMID

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Abstract

Legalizing marijuana, whether for medical use, for recreation, or for recreation under the guise of medicine, has raised concerns about stoned drivers imperiling the safety of other drivers. In response, legislators have set legal limits for THC (Delta-9 tetrahydrocannabinol), the primary psychoactive component in marijuana1. Legislators in Washington and Montana have set a THC per se limit of 5 ng/ml in whole blood. Legislators in Colorado have set a THC permissible inference level of 5 ng/ml in whole blood. None of these states have legal limits for drugs other than marijuana and alcohol. Other states from California to Maine and Florida are considering similar legislation. Although well-intended, these and other efforts to set a 5 ng/ml THC legal limit are badly flawed. The marijuana lobby has consistently attacked 5 ng/ml THC level as being too low. They claim that people who self-medicate on marijuana have residual blood levels of THC well above 5 ng/ml without being impaired, that heavy users of marijuana develop a tolerance for marijuana's impairing effects, and that there is no scientific basis for a 5 ng/ml THC legal limit (Elliott, 2011). Contrary to the marijuana lobby's stance, we assert that the 5 ng/ml THC level is far too high, but agree that there is no scientific basis for a 5 ng/ml THC legal limit. Furthermore, there is no scientific basis for any impairment-based THC per se limit. A THC per se limit may be established based on public policy beliefs, but not based upon proofs of impairment. A THC per se limit of 5 ng/ml is so high that it amounts to a license to drive stoned, since most marijuana-impaired drivers test well below 5 ng/ml THC in whole blood.

© 2016. Institute on Global Drug Policy

Keywords: Cannabis impaired driving

Language: en