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‘Cannabis Light’ Doesn’t Negatively Impact Simulated Driving Performance


‘Cannabis light’ is very popular in many parts of the world right now, particularly in Europe. The term is used to describe cannabis that is low in THC and high in CBD. Many governments around the globe have reformed their laws and/or regulations in recent years to permit cannabis that is low in THC.

The rise in the use of low-THC products has generated questions regarding their safety as it pertains to driving impairment. According to a recent study conducted in Switzerland involving driving simulations, the products do not negatively impact driving performance. Below is more information about it via a news release from NORML:

Basel, Switzerland: The inhalation of high-CBD/low-THC cannabis doesn’t adversely impact driving abilities, according to clinical trial data published in the International Journal of Legal Medicine.

A team of Swiss researchers assessed the impact of CBD-dominant (< 1 percent THC) cannabis on simulated driving abilities.

Consistent with other studies assessing the influence of CBD on psychomotor skills, investigators acknowledged, “No significant differences regarding driving ability were found between the CBD-cannabis products and placebo.”

However, researchers reported that participants nonetheless tested positive for trace levels of THC in their blood in the hours immediately following their use of low-THC herbal cannabis. As a result, they cautioned that some consumers could potentially run afoul of traffic safety laws that impose per se limits for the presence of THC in blood despite having never been impaired.

Five states – Illinois, Montana, Ohio, Pennsylvania, and Washington – impose various per se limits for the detection of trace amounts of THC in blood while ten states (Arizona, Delaware, Georgia, Indiana, Iowa, Michigan, Oklahoma, Rhode Island, Utah, and Wisconsin) impose zero tolerant per se standards. In these states, it is a criminal violation of the traffic safety laws to operate a vehicle with detectable levels of THC in blood – even absent any demonstrable evidence of psychomotor impairment.

NORML has long opposed the imposition of THC per se thresholds for cannabinoids in traffic safety legislation, opining: “The sole presence of THC and/or its metabolites in blood, particularly at low levels, is an inconsistent and largely inappropriate indicator of psychomotor impairment in cannabis consuming subjects. … Lawmakers would be advised to consider alternative legislative approaches to address concerns over DUI cannabis behavior that do not rely solely on the presence of THC or its metabolites in blood or urine as determinants of guilt in a court of law. Otherwise, the imposition of traffic safety laws may inadvertently become a criminal mechanism for law enforcement and prosecutors to punish those who have engaged in legally protected behavior and who have not posed any actionable traffic safety threat.”

Full text of the study, “Effect of vaporizing cannabis rich in cannabidiol on cannabinoid levels in blood and on driving ability – A randomized clinical trial,” appears in the International Journal of Legal Medicine. Additional information is available from the NORML Fact Sheet, ‘Marijuana and Psychomotor Performance.’