In California, a first-time driving under the influence (DUI) is a misdemeanor offense. However, there are a few exceptions where even a first time DUI may be charged as a felony.
Under Vehicle Code section 23550.5, subdivision (b) a conviction for a first time DUI within a ten-year period can result in a felony conviction punishable by imprisonment in state prison if the defendant had been previously convicted of gross vehicular manslaughter while intoxicated (Penal Code section 191.5) or vehicular manslaughter (Penal Code section 192.5). While section 191.5 has the element of intoxication, section 192.5 does not. Furthermore, while the DUI statutes generally have a ten-year look back window in prosecuting multiple DUI offenses, section 23550.5(b) does not.
Example: In 2008, Henry, then 18 years old was racing his car in an unlawful exhibition of speed in violation of Vehicle Code section 23109. His vehicle went out of control and broadsided another vehicle killing both occupants in that vehicle. Henry was not intoxicated. He was convicted on two counts of vehicular manslaughter (Penal Code section 192.5). Twelve years later, Henry was arrested for driving under the influence pursuant to Vehicle Code section 23152, subdivisions (a) and (b). It was his first ever DUI arrest. Normally a first time DUI is a misdemeanor and very rarely, if ever, is punished by any jail time at all. But because Henry had a historical conviction of vehicular manslaughter, his DUI was charged as a felony and he faced a potential sentence of imprisonment.