Section 23152 of the California Vehicle Code says that driving under the influence of drugs and / or alcohol is a misdemeanor. Everyone knows that legal limit for alcohol is 0.08% -- if prosecutors can prove that your blood alcohol concentration was greater than 0.08% at the time of driving, you are guilty of DUI.
Marijuana is a lot more complicated than alcohol, though. Even though adults over 21 may now legally grow, use and possess marijuana in California, it is still illegal to operate any motor vehicle (a car, a boat, a golf cart, a jet ski, a moped...anything with a motor) while you are "impaired" by cannabis.
Unlike alcohol, there is no magic number to objectively determine whether or not someone is too stoned to legally drive. To convict you of driving under the influence of marijuana, the prosecutor must prove that you operated a vehicle while you were in such a condition that you could not exercise the skill and care of an ordinary, sober driver (whatever that means).
If you are stopped by police and an officer suspects that you've been smoking, he will begin the standard investigative procedures: he will ask you a series of questions about where you're coming from and where you're going. He'll ask if you're under the care of a doctor of if you've had any recent surgeries. He'll ask when you slept last and whether or not there is anything mechanically wrong with your car. The officer also will probably invite you to participate in a series of field sobriety tests (walk a line, touch your nose, stand on one foot, estimate 30 seconds, etc.). You are not legally required to take these tests. You'll be arrested either way, so I'd advise that you provide as little evidence as possible to be used against you later in court. If you are stopped on suspicion of DUI, you should POLITELY decline to play the roadside Olympics. You should also avoid talking yourself into trouble. Do not admit that you recently smoked, drank, or consumed any controlled substance.
After you are arrested, you must provide a blood sample. If you refuse to submit to a chemical test after you have been lawfully arrested on suspicion of DUI, the DMV will automatically suspend your driver's license for one year.
To make their case against you in court, the DA will introduce evidence that were driving poorly before you were pulled over. A police officer will testify that he stopped you because you were driving too slowly, you were drifting within your lane, you made an unsafe lane change, etc. The officer will testify that you "appeared disoriented" and "had difficulty following instructions". He will probably also testify about the smell of burnt cannabis emitted from your breath and from the interior of your vehicle. If you agreed to perform field sobriety tests, the officer will testify that you failed them all miserably, even if you feel like you nailed them. Based on the totality of his observations, the officer will testify, he formed the opinion that you were dangerously impaired by marijuana and that you could not safely operate a vehicle.
The DA will also use your blood test results to build their case against you. Your blood test will give two important numbers: your levels THC metabolites (also called "carboxy-THC", or "COOH-THC"), and your levels of active THC (also called "delta-9-THC"). THC metabolites remain in your blood system for weeks after your last usage. They are not psychoactive and are not indicative of current impairment. They only prove that you have consumed marijuana some time within the past several weeks. This number is not relevant to determining whether or not you were dangerously impaired at the time of driving, but it may be relevant to demonstrate that you have a high tolerance for the drug.
Your delta-9-THC numbers are slightly more valuable in determining your current level of impairment. Delta-9-THC is the chemical that is CURRENTLY active in your bloodstream. Your delta-9-THC concentration is still not a completely reliable way to determine a driver's degree of impairment, though. Since cannabis affects users so differently, there is not a strong correlation between a person's delta-9-THC levels and his or her actual impairment. A relatively inexperienced marijuana user might be very impaired at a low THC level, where a more experienced smoker might barely feel any effect at the high blood-THC concentration. Consider also that indica-dominant strains might affect a user differently than sativa-dominant strains, and that standard field sobriety tests are designed to detect alcohol impairment, not cannabis impairment. Most "experts" will testify that a driver is more likely to be involved in a collision when his or her active THC level is greater than 5 ng/ml, and that the risk is multiplied by the presence of alcohol, but this is controversial.
Police and prosecutors are aggressively working to crack down on "drugged driving", including driving under the influence of legal drugs (marijuana, prescription drugs, sleep aids, etc.). The Orange County District Attorney's Office has several deputy prosecutors who are specially trained and specifically assigned to process DUID cases full-time. They take these cases seriously, but that doesn't mean that they have the advantage. In my experience, their aggressive policy often means that they choose to pursue cases even when the evidence is weak.
If you or a loved one has questions about DUI or driving under the influence of drugs in Southern California, call us for a free attorney consultation. (714) 449-3335. Ask for John.
Thanks for reading.
