Whether you need to use an interlock after your first DUI conviction depends on the state where you live. In 30 states and the District of Columbia, first-time offenders must install an interlock. These states are Alabama, Alaska, Arizona, Arkansas, Colorado, Connecticut, Delaware, District of Columbia, Hawaii, Idaho, Illinois, Iowa, Kansas, Kentucky, Louisiana, Maryland, Mississippi, Nebraska, New Hampshire, New Jersey, New Mexico, New York, Oklahoma, Oregon, Tennessee, Texas, Utah, Vermont, Virginia, Washington, and West Virginia.
In Florida, Michigan, Minnesota, North Carolina, Pennsylvania, Rhode Island, South Carolina, and Wyoming, only high first-time offenders with a high BAC (between 0.1 and 0.17, depending on the state) need to install an interlock. Georgia, Maine, Massachusetts, Missouri, and Ohio require an interlock for repeat offenders only. California, Indiana, Montana, Nevada, North Dakota, South Dakota, and Wisconsin have no statewide requirements on interlocks, but judges can order their use at their discretion, including for first-time offenders.