A prior conviction from another state may be used here in California – in court, and at the DMV.
However, there are limitations. The prior conviction must be for an offense, which would be a DUI if committed here. That may sound obvious, but consider that most other states have significantly different laws. For example, some states used to make it illegal to drive with a BAC of .08%, while California still had the .10% limit. That meant, you could be convicted in your state with a BAC of .09%, but if you had committed the same offense here, you would not be guilty. There are significant differences from state to state, which may prevent California from using your prior conviction agaisnt you here.
In court, a challenge to the use of the prior is made by a motion. The motion is called a motion to strike. This is made under Vehicle Code section 41403. It is very important that this is done correctly, because the law only allows you to attempt this once! If it is granted, the prior may not be used against you in court or at the DMV. If the motion is not granted in court, then the criminal case against you in CA will include the prior from the other state – but there is another way to get it removed for DMV purposes only. To do this, you need to first request it be removed by filing a DL-207 form. It will be denied by the DMV. Then you are entitled to have that denial reviewed by a real judge in court under CCP section 1085.
You may also read the interstate compact yourself at: Interstate Compact
