Marijuana DUI Standards Continue to Perplex Law Enforcement

Eyelid tremors? Slow movement? Green tongue? If you ask law enforcement officers, these are indicators of a driver’s marijuana intoxication, used to justify traffic stops and arrests for driving under the influence of the drug. The problem is, if you ask a Los Angeles marijuana DUI defense lawyer, some of that is complete junk science.

There is no doubt that THC, the psychoactive compound in marijuana, can result in a person’s intoxication, weakening one’s ability to focus and react quickly. What is in doubt is the best way to ascertain whether someone has crossed that threshold. We know that a person with a blood-alcohol concentration of 0.08 percent or higher can be reasonably judged as intoxicated, based on the science of how we know alcohol moves through the body – very quickly. But this kind of measurement of THC concentration won’t give you an exact answer because the drug is processed through the body at a much slower rate. It remains detectable in the body not just for hours but days or weeks, the concentration level a potential indicator of whether one is a regular user but not an accurate indication that one is too impaired to drive.

Despite this, at least five states have adopted a so-called “per se” law that outlaws driving if one’s blood level of THC exceeds a set amount. Most others, including California, are relying heavily on the training and testimony of “drug recognition experts.” Their methodology includes a series of assessments, including the standard field sobriety test, which might include exercises like the one-leg stand. Civil rights activists in several states have questioned whether DRE training is adequate and whether the program used to validate the results is backed by both the medical and scientific community. The New Jersey Supreme Court is slated to consider one such case in the coming months.

Some reported methods and justifications given by DREs are extremely troubling. Consider, for instance, the “green tongue” standard. USA Today reported that in numerous DUI cases across the country, law enforcement indicated green coating on the suspect’s tongue as an indicator of impairment. This is taught in DRE courses across the world – yet there is no cited scientific basis for it. There is no indication that a green tongue is an indicator of marijuana ingestion, let alone intoxication. In fact, the Washington Court of Appeals ruled in a 2000 marijuana DUI arrest case that the trooper’s reported observation of the driver’s green tongue wasn’t enough reasonable suspicion to rise to the level of searching a vehicle. “…We are skeptical as to its accuracy and find no case stating that marijuana usage leads to a green tongue.” The Utah Court of Appeals reached the same conclusion in a 2004 marijuana DUI case.

A former DRE in Los Angeles said the origins of the green tongue theory came from a 1986 handbook published by the California Highway Patrol, which showed a picture of a “green-coating tongue of a marihuana-hashish smoker.” He was quoted as saying he’s only ever seen one case of a green-tongued marijuana user in his career – on St. Patrick’s Day, when the driver had been smoking marijuana but also drinking green beer.

There are also two peer-reviewed articles that law enforcement agencies sometimes cite – but neither was specifically looking to establish that smoking marijuana causes a green coating on the tongue.

Although this indicator has been listed in law enforcement training manuals as recently as 2015, most stipulate that there should be more than one indicator. Similarly, the smell of marijuana alone is likely an unwise indicator of intoxication, particularly given how many states have moved to legalize the drug.

With more states increasingly legalizing marijuana for recreation, we’re likely to see an increase in marijuana DUI cases. A recent study by the AAA Foundation for Traffic Safety indicated there are a growing number of crashes involving drivers who test positive for marijuana after a state legalizes a drug. We must consider that with legalization, the overall population of drivers would show higher rates of those testing positive for the drug – because it’s more readily accessible. However, we must bear in mind again that testing positive for the drug doesn’t automatically mean the driver was impaired.

The Los Angeles CANNABIS LAW Group represents growers, dispensaries, ancillary companies, patients, doctors and those facing marijuana charges. Call us at 949-375-4734.

Additional Resources:

Smoking weed: When is someone too high to drive? Jan. 3, 2020, Kaiser Health News