With DUI fatalities soaring by 53% in the state between 2019 and 2025, the California State Assembly passed AB 366, which requires all DUI offenders to use an ignition interlock device (IID) on their vehicles.
This is an extension of the previous program, where the use of IIDs only applied to those convicted of two or more DUIs. The new bill took effect on January 1, 2026 and comes down hard by imposing a fine of up to $5,000, up to six months in county jail, or both if drivers fail to comply with the IID requirement.
California isn’t the first state to implement IID laws, as 33 others already have them on the books. Available data suggests that IIDs stopped over 30,000 drunk drivers from starting a vehicle in 2023.
