A previous DUI/DWI conviction in another state may be included as a previous conviction and elevate or enhance the charge for a subsequent DUI/DWI in the driver’s current state of residence—just as if the driver had been convicted of the previous DUI/DWI offense in the driver’s current state of residence.

Whether a previous DUI/DWI conviction in another state is included or stacked on a DUI/DWI charge in the driver’s current state of residence will depend on whether the prosecutor on the current charge becomes aware of the previous conviction. The prosecutor will often become aware of a previous conviction by searching the National Driver Register database—which may include information regarding a driver’s license suspension or revocation provided by the other state in which the driver previously lived and was convicted of DUI/DWI. And if a driver receives a DUI/DWI while visiting another state, the police will notify the Department of Motor Vehicles (DMV) in both the state where the driver was charged with DUI/DWI and the state of the driver’s residence that issued the driver’s current license.

These laws vary from state to state and their application often includes some prosecutorial discretion on whether to include or stack a previous conviction for a DUI/DWI charge in another state on a current DUI/DWI charge in the driver’s state of residence. Some states include, calculate, or stack such a previous DUI/DWI conviction only when the law violated in the other state is sufficiently similar to the DUI/DWI law in the state where the current charge is pending.

In California, a previous DUI/DWI conviction from another state can be considered a prior offense and may enhance the penalties for a subsequent DUI/DWI charge in California. This is in accordance with California Vehicle Code Section 23626, which states that a conviction from another jurisdiction that prohibits the same or similar conduct as California's DUI laws is deemed a prior DUI conviction. When a person is charged with a DUI in California, the prosecutor may check the National Driver Register database to determine if there are any prior DUI/DWI convictions from other states. If a prior out-of-state DUI/DWI conviction is discovered and it is similar enough to California's DUI laws, it can be used to elevate the current DUI charge, leading to more severe consequences such as longer jail time, higher fines, and extended license suspension periods. The application of this law involves prosecutorial discretion and a legal analysis to ensure the out-of-state offense is comparable to California's DUI statutes.