California law prohibits driving under the influence of alcohol and drugs, including legal cannabis. The legal limit for blood alcohol concentration (BAC) is 0.08%. However, the state has not established a specific blood concentration limit for THC, the active compound in cannabis.
Instead, the focus is on impairment. Law enforcement can charge you with a DUI if they determine you have used cannabis and the drug has compromised your ability to drive safely.
To determine impairment, law enforcement officers may administer standard field sobriety tests, such as the walk-and-turn test, one-leg stand and horizontal gaze nystagmus test. These tests help assess a driver’s coordination, balance and cognitive abilities.
Drug Recognition Experts
In cases of suspected drug impairment, police officers trained as Drug Recognition Experts may evaluate a driver. DREs have experience in identifying drug-induced impairment, including the effects of cannabis.
Oral fluid testing
California has implemented oral fluid testing as a tool to detect recent cannabis use. However, this test is not yet widely used, and its reliability is a subject of ongoing research.
Medical cannabis users
While state residents have a legal right to use medical cannabis, they are still subject to DUI regulations. You can receive a DUI even with a prescription if the drug impairs your driving ability.
Statista says that 6.7 million California residents use cannabis, more than in any other state. If you receive a conviction for cannabis DUI, the severity of the penalties varies based on factors like prior convictions and the level of impairment. For drivers under 21, there is a zero-tolerance policy. Any detectable amount of cannabis in the system can result in penalties, including a one-year driver’s license suspension.