Vehicle Code section 312

The term “drug” means any substance or combination of substances, other than alcohol, which could so affect the nervous system, brain, or muscles of a person as to impair, to an appreciable degree, his ability to drive a vehicle in the manner that an ordinarily prudent and cautious man, in full possession of his faculties, using reasonable care, would drive a similar vehicle under like conditions.

Source: Section 312, https://leginfo.­legislature.­ca.­gov/faces/codes_displaySection.­xhtml?lawCode=VEH§ionNum=312.­ (updated Jan. 1, 1971; accessed Jun. 25, 2025).

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Verified:
Jun. 25, 2025

§ 312's source at ca​.gov