Bureau of Crime Statistics and Research

​Alcohol interlock devices reduce repeat drink driving

Release Date: Tuesday, 9 August 2022

Links to report summary:-

A new study by the Bureau of Crime Statistics and Research (BOCSAR) has found that breath test devices installed in the vehicles of high-range drink drivers significantly reduces repeat drink-driving.

Since 2015, the Mandatory Alcohol Interlock Program (MAIP) has allowed NSW courts to order high-range and repeat drink drivers to install an alcohol interlock breath test device in their cars, trucks or motorcycles (or face a 5-year disqualification period). The alcohol interlock device prevents the vehicle's ignition from starting if it detects alcohol in the driver's breath.

BOCSAR compared outcomes for 3,273 first-time high-range drink drivers who took up interlock devices with 5,367 first-time mid-range offenders who recorded a BAC just below the high-range threshold and were therefore ineligible for a device.

The study found that high-range drink drivers were:

  • 86% less likely to commit a new drink driving offence while the device was installed; and
  • Slightly less likely to commit a further drink driving offence in the 2 years after the interlock was removed.

There was no impact on driving while disqualified or road crashes, despite MAIP enabling offenders to return to driving sooner.

"Research suggests that high-risk drink drivers are less likely to comply with traditional court-imposed sanctions, leading to higher rates of driving whilst disqualified and alcohol-related crashes" said Jackie Fitzgerald, Executive Director of the Bureau of Crime Statistics and Research. "Given the accumulating evidence for their effectiveness, increasing the uptake of alcohol interlocks should be a priority for government".

Further enquiries: Jackie Fitzgerald, Executive Director, BOCSAR 0423139687

Email: bcsr@justice.nsw.gov.au

Copies of the report: www.bocsar.nsw.gov.au