Section 23152 of the California Vehicle Code prohibits anybody from operating a vehicle while they are under the influence of drugs or alcohol. The DA doesn't need to prove that you were on a public road. They don't even need to prove that the vehicle was an automobile.
I've had clients accused of riding dirt bikes, jet skis and golf carts while drunk (not all at the same time). In California, all of those situations can be treated as "DUI". Hiring an experienced DUI defense attorney can be very helpful in these cases, though. Often, the kind of officers who arrest drunken dirt bikers, boaters or golfers are inexperienced in making those types of arrests. They don't have the training or resources to properly prosecute DUI cases. Park rangers and harbor patrol officers might mishandle evidence or fail to file documents in a timely manner.
You can even be cited for riding a bicycle while drunk in California ("Cycling Under the Influence, or "CUI"), but those cases are treated a little differently. CUI is an infraction only and not a misdemeanor, so the court cannot impose jail time or probation. Bicycles obviously aren't "motor vehicles", so the 0.08% BAC limit doesn't apply, and the DMV will not suspend your driver's license or impose mandatory classes. To be guilty of CUI, the officer must prove that you were so impaired by alcohol and /or drugs that you could not operate a bicycle with the skill and care of an ordinary cyclist (whatever that means). If you are cited for CUI, you may demand a breath or blood test, but you are not required to take one.
If you or a loved one has questions about DUI in California, call us for a free attorney consultation. (714) 449-3335. Ask for John.