After ______ DUI convictions within 10 years, the installation of an ignition interlock device becomes mandatory.

After two DUI convictions within 10 years, the installation of an ignition interlock device becomes mandatory. This device will prevent the vehicle from starting if the driver's blood alcohol concentration (BAC) is at or above a preset level. [8-7 Driving Under the Influence, Chapter 8 How to Protect Your Driving Privileges, Idaho Driver's Manual]