Field Sobriety Tests May be Insufficient for DUI Cases Involving THC

Field Sobriety Tests May be Insufficient for DUI Cases Involving THC

Field Sobriety Tests May be Insufficient for DUI Cases Involving THC



Tetrahydrocannabinol, commonly known as THC, is the main psychoactive component found in cannabis. Certain synthetic formulations of THC are FDA approved and can be used in chemotherapy treatment. Moreover, cannabis with THC is becoming legal in more states, allowing it to now be used for medicinal and recreational use. However, the FDA classifies cannabis under Schedule 1 which means it is forbidden in any products for off-label uses.



The current enforcement of Cannabis impaired driving relies on behavioral methods of detecting impairment. Most of the enforcement for Cannabis impaired driving relies on officer conducted field tests. However, these were primarily created and validated based on alcohol ingestion, making them not necessarily accurate for drug ingestion detection. How useful officer conducted field tests are to detecting Cannabis in a drug related DUI still remains unclear.



A study by UCSD shows that a field sobriety test for THC might not hold enough weight, on its own, to determine impairment while driving. In the study, researchers at UCSD’s Center for Medicinal Cannabis Research performed a double-blind, placebo-controlled randomized clinical trial. This trial looked to determine how accurate field sobriety tests can identify drivers under the influence of THC.

The study included 184 adult cannabis users between the ages of 21 and 55. The experiment was conducted where 63 participants received a placebo cannabis cigarette while 121 participants received a THC cannabis cigarette. The participants who consumed the THC reported a median “highness” level of 64 on a scale of 0 to 100. This essentially suggests that the content was sufficient enough to achieve significant intoxication. Trained law enforcement officers were then brought in to perform field sobriety tests during four different time intervals, roughly one, two, three and four hours after smoking. The results found that officers classified a significantly higher proportion of participants in the THC group as being impaired based on the field sobriety tests compared to the placebo group at three of the four time points measured.

Study participants also completed a driving simulation. Their performance in the simulation was “significantly associated with the results of select field sobriety tests,”. The researchers concluded that existing field sobriety tests “may be sensitive enough” to detect those under the influence of cannabis. However, the overlap in poor test performance between the placebo and THC groups, and the high frequency at which officers suspected this was because of THC consumption, suggest that field sobriety tests alone may be insufficient to identify THC-specific driving impairment, they wrote.


San Diego THC DUIs

According to the San Diego Tribune, drugged driving has been on the increase since the legalization of Marijuana in California. Nearly twice as many drivers have been convicted of a drug related DUI than those of an alcohol related DUI in recent years.

If you are in the Greater San Diego area and find yourself in a situation involving a THC or drug related DUI, contact Rick Mueller. Rick Mueller is a CDLA Specialist with a proven track record to help you with your specific situation.


Field Sobriety Tests May be Insufficient for DUI Cases Involving THC


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