Now that recreational marijuana is legal in California, law enforcement agencies are racing to train officers in roadside drug recognition. Since pot became legal, the Orange County crime lab has seen a 40 percent increase in requests to process blood samples related to driving under the influence of marijuana arrests. Whether there actually is an increase in marijuana-influenced drivers or the cops have increased their suspicions since legalization, one thing is for sure: the roadside detection of driving under the influence of marijuana is much harder for the cops than figuring out if a driver is under the influence of alcohol. Hence, the rush to train more officers as drug recognition experts.

The officers, who are trained to become drug recognition experts, receive an advanced certification which allows them to testify in court as an expert. While the specific focus on driving under the influence of marijuana is prompting the rush to certify more experts, these experts are trained to recognize symptoms of not only Cannabis use, but of six other categories of drugs:

  • Central Nervous System Depressants (examples include commonly prescribed drugs such as Prozac, Zoloft, and Paxil);
  • Central Nervous System Stimulants (examples include cocaine, amphetamines, and methamphetamines);
  • Hallucinogens (examples include LSD and Ecstasy);
  • Dissociative Anesthetics (most common example is PCP);
  • Narcotic Analgesics (examples include opium and heroin, but also include many prescribed drugs such as Vicodin and oxycontin); and
  • Inhalants (examples include inhaling paint, paint thinners, and various gases that cause mind-altering effects when inhaled).

A person driving under the influence of marijuana (or any Cannabis product) as well as the drug categories listed above is unlawfully driving under the influence if the drug affects the driver’s ability to drive safely.

The experts are trained in a systematic method using a 12-step protocol. Key among these tests are examinations and observations of the subject’s eyes. Also utilized are psychophysical tests, which are those walking, balance, and finger to nose tests we are all familiar with. Other examinations and observations include examining the subject’s muscle tone and the officer’s observations of the subject’s behavior.

Critics charge that the drug recognition protocol is not an exact science and the officers conducting these tests are not scientists or medical experts. However, in defense of the drug recognition expert certification, law enforcement agencies point to the many hours of training required to gain the certification. Indeed, the training is rather rigorous: the officer must attend 72 hours of class time that covers everything from the initial evaluation to testifying in court. After completion of the classes, the officer must perform a minimum of 12 drug evaluations under the supervision of a certified drug recognition expert instructor and of those 12 evaluations, the officer must be right at least 75 percent of the time as corroborated by a toxicological test.

Even with this nationally recognized drug recognition protocol, prosecuting persons for driving under the influence of marijuana is much more difficult than prosecuting those for driving under the influence of alcohol for a variety of reasons. At present, there is not even a standard threshold at which THC levels are considered, per se, to cause impaired driving. And there are no roadside breathalyzer-type devices (yet) that could give an accurate reading of the driver’s THC blood content.

Whether you are under the influence of marijuana or alcohol, it is always an excellent idea to leave the driving to someone else, even if you think you are fine to drive. But if you or someone you care about made the wrong choice and are now facing a DUI or a DUID, Orange County DUI defense attorney William Weinberg is available for a free consultation. Contact him at or by calling his Irvine office at (949) 474-8008.