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 Pennsylvania (PA), a previous DUI/DWI conviction from another state can be considered when determining the severity of charges and penalties for a subsequent DUI/DWI offense. This is in line with Pennsylvania's efforts to discourage drunk driving and penalize repeat offenders more harshly. If the out-of-state DUI/DWI conviction is substantially similar to what Pennsylvania law prohibits, it may be treated as a prior offense. This can elevate the current DUI/DWI charge, leading to increased penalties such as longer license suspensions, higher fines, and possibly more severe jail sentences. Prosecutors in Pennsylvania may become aware of prior out-of-state DUI/DWI convictions through the National Driver Register database, which tracks license suspensions and revocations across states. Additionally, if a Pennsylvania resident is convicted of a DUI/DWI in another state, both the state where the offense occurred and Pennsylvania's Department of Motor Vehicles will be notified, potentially affecting the driver's license status in their home state. The application of these laws involves prosecutorial discretion and a legal analysis to determine the similarity of the laws between the states involved.