DUI Related Terms And Definitions

To be convicted of a DUI, the prosecution must prove beyond a reasonable doubt that you drove a vehicle while under the influence of any alcoholic beverage or drug. VC23152(a).

In a typical alcohol related DUI, the prosecution will also charge subsection (b) of the same codesection. They will be required to prove that you drove a vehicle with a BAC of 0.08 or higher.

Below are some definitions that are used by the court in DUI cases. While some definitions are common sense, others may be surprising. Contact our office to speak with a DUI lawyer who can answer your questions about your case.


Driving is any voluntary movement of a vehicle and can be proven by circumstantial evidence. In other words, you can be convicted even if no one saw you driving but other evidence leads to a reasonable conclusion that you probably were driving. Also, you can be convicted of a DUI if you were simply steering a car that someone else was pushing.


Vehicle Code section 670 defines a vehicle as "a device by which any person or property may be propelled, moved, or drawn upon a highway, excepting a device moved exclusively by human power or used exclusively upon stationary rails or tracks."

What qualifies: Cars, trucks, motorcycles, scooters, snowmobiles, etc.

What does not qualify: handicap wheelchairs and motorized tricycles and quadricycles, operated by persons who, because of physical disability, are unable to move as pedestrians. California Vehicle Code sections 415 and 467.

Under the Influence

A person is under the influence of an alcoholic beverage or drug or the two combined when as a result of drinking the beverage, using the drug, or both, his or her physical or mental abilities are so impaired that he or she no longer has the ability to drive a vehicle with the caution characteristic of a sober person of ordinary prudence under the same or similar circumstances.

If it is proven beyond a reasonable doubt that the driver had a BAC of 0.08 percent or more, the jury may presume that the driver was under the influence of alcohol at the time of driving.

Alcoholic Beverage

An "alcoholic beverage" is a liquid or solid intended to be consumed that contains ethanol. Ethanol is commonly known as drinking alcohol. See Vehicle Code section 109 Alcoholic beverages include intoxicating liquor, malt beverage, beer, wine, spirits, liqueur, whiskey, rum, vodka, cordials, gin, and brandy, and any mixture containing one or more alcoholic beverages whether found or ingested separately or as a mixture. California Vehicle Code section 109. Business & Professions Code section 23004.

Yes, it is possible depending on your size and the type of beverage to have only one mixed alcoholic drink and be under the influence for the purposes of a DUI.


"Drug" means any substance or combination of substances, other than alcohol, that could so affect the nervous system, brain, or muscles of a person as to impair, to an appreciable degree, his or her ability to drive a vehicle in the manner that an ordinarily prudent and cautious person, in full possession of his or her faculties, using reasonable care, would drive a similar vehicle under like conditions. California Vehicle Code section 312.

Contrary to common belief, the drug need not necessarily be an illegal drug to qualify under the DUI laws. A person can be considered under the influence of a drug even if that drug was lawfully prescribed to the person. Strong sleep aids and pain medication are the main drugs encountered in prescription drug DUI cases.