Despite the legalization of marijuana use in California, the law still prohibits driving while impaired by marijuana use. California's Vehicle Code includes marijuana among the substances that can cause impairment and make it illegal to drive.
Legalization may have the effect of putting law enforcement agencies on increased alert, as they expect a rise in stoned driving. There are some important differences in marijuana DUIs from alcohol or illegal drug DUIs.
Prosecutors must show use and impairment
Because marijuana use is now legal, just having evidence that you used it is not enough to sustain a DUI conviction. Prosecutors must also show actual impairment.
Typical ways to prove use include chemical testing, field sobriety tests, police officers' testimony about your demeanor and indicators of drug use, and assessments by Drug Recognition Experts (DREs).
Chemical testing and its limits
Chemical testing for marijuana tends to be unreliable. Although most types of chemical testing generally do a good job of detecting the presence of marijuana, by measuring the level of THC compounds, they do not show when you ingested the substance. Most people stop being affected by marijuana within a few hours, while chemical tests may detect compounds from marijuana consumed as much as several weeks ago. Some counties have recently introduced mouth swabs for saliva analysis, which may produce more accurate results.
Even an accurate chemical test will not mean a slam dunk for the prosecution. Unlike alcohol, there is no accepted level of marijuana compounds that automatically signifies impairment. This is because the effects of marijuana can vary greatly, and experts disagree about how much THC impairs. Thus, prosecutors will still need to prove that ingesting marijuana impaired your driving.
Officers at the scene of a stop often look for physical indications such as rapid breathing, red eyes, the smell of marijuana, the presence of paraphernalia and delayed reactions. They may also administer a field sobriety test, which assesses physical coordination and cognitive reactions.
While a marijuana DUI conviction can have serious consequences, it is not always easy for prosecutors to prove. An experienced defense attorney can identify weaknesses in the case against you and help you fight these charges.