Alcohol Interlock Devices

An ignition interlock is a device which prevents a vehicle from starting if the driver has been drinking. The device works like a breathalyzer, measuring the alcohol in a person’s system. If the amount of alcohol on the driver’s breath exceeds a pre-programmed level, then the interlock temporarily locks the vehicle’s ignition.

To take the test, the driver simply delivers a breath sample into the device. If the sample is good, then the vehicle will start as usual. If alcohol is detected, the driver must wait before testing again. The first time alcohol is detected, the wait time is a few minutes, but if subsequent tests are failed the driver is locked out for increasingly longer periods.


Costs associated with installing and servicing alcohol interlocks must be paid by the participant. It is estimated that the standard costs to participants will include interlock device installation, monthly device leasing, regular device servicing (monthly or bi monthly) and device removal at the end of the mandatory interlock period. These standard costs are estimated* to be about $2,200 a year.

The three accredited interlock service providers in NSW are:

Freedom to Drive

In NSW we can use ignition interlocks as an alternative or to revoking driving privileges. Interlock devices prevent drink driving while giving those with PCA / DUI or drug driving convictions the opportunity to work, attend school, and perform other essential tasks. The devices are widely seen as beneficial both to the offender and the public.

Request an Interlock Assessment