Mothers Against Drunk Driving says car-locking systems have stopped more than 1.77 million drivers from getting on the roads since states first passed laws requiring some offenders to install them in 1999.
The report on ignition interlock systems was released Wednesday. It compiles the number of times the 11 major manufactures of the devices say they have stopped people from using their vehicles nationwide.
The device, the size of a cellphone, is wired into a vehicle. A convicted drunk driver must blow into it for a blood alcohol reading to start the car.
MADD national president Colleen Sheehey-Church says the devices could save more lives if every offender were required to use them after his or her first arrest.
Currently, 25 states require all offenders to install the devices. Other states require them only for certain levels of offenses or blood alcohol content, or give judges discretion.