Driving under the influence of drugs, or DUID, is essentially the same as a DUI with alcohol. The code section reads: “It is unlawful for a person who is under the influence of any drug to drive a vehicle. “
In essence, the prosecutor has to prove that the defendant drove a vehicle, and when s/he drove, s/he was under the influence of a drug. The drug can be an illegal substance, a prescribed medication or even an over-the-counter medicine that could affect the nervous system, brain, or muscles of a person.
“Under the influence” is the hardest element for the government to prove. According to the California Jury Instructions (2110), “A person is under the influence if, as a result of…taking a drug, his or her mental or physical abilities are so impaired that he or she is no longer able to drive a vehicle with the caution of a sober person, using ordinary care, under similar circumstances.”