A new law in Alabama requires people convicted of drunk driving to install ignition locks on their vehicles.

The new law took effect Sept. 1. It requires convicted drunk drivers with a blood-alcohol level of .15 or higher to install an ignition lock in their vehicle.

Before starting a car, those drivers must exhale into a breathalyzer. If they have been drinking, the lock will prevent the engine from starting.

The Anniston Star reports that first- and second-time offenders must keep the locks on their cars for two years. A third conviction would force a motorist to use a lock for four years, while a fourth conviction would require that the system stay installed for five years.