It is only a felony DUI with an accident in Vista Courts and throughout California if the accident was caused by the DUI driver and another person is injured or killed. If it is an accident with no one else injured other than the DUI driver, then it is still a misdemeanor. An accident, however can cause increased penalties even as a misdemeanor that are greater than a DUI without an accident.
A DUI can be either a misdemeanor or a felony not only in Vista, but anywhere in California. A misdemeanor is any crime where the maximum available custody is 1 year or less in county jail. A felony is any crime where the maximum available sentence includes state prison or prison commit in excess of 1 year, regardless whether the defendant gets any custody. A felony "Drunk Driving" is any case which includes an injury to another person negligently caused by an impaired driver or driver with a blood alcohol level of .08 or more. Also any fourth DUI within 10 years is a felony as is any DUI within 10 years of a felony DUI.