Ignition interlock devices, intended to prevent cars from starting if alcohol is detected in a driver’s breath, can be an effective tool to curb drunk driving. Governor Andrew Cuomo’s DMV rule reforms include an interlock requirement for drivers who are issued restricted licenses after multiple DWI convictions. In 2009 the state legislature passed Leandra’s Law, which among other things mandates six months of interlock use for drivers convicted of DWI.

But an audit released Thursday by State Comptroller Tom DiNapoli found that the majority of people who are supposed to be using ignition interlocks aren’t installing them. DiNapoli says the compliance rate is 5 percent in New York City and just 26 percent statewide.

DiNapoli’s office says 2,166 drivers in NYC were ordered to use interlocks from 2010 to 2014, and of those, only 111 devices were installed. “[T]here was little evidence that NYC Probation routinely followed-up with offenders to determine if they owned vehicles in which devices should be installed, or did not drive motor vehicles during the periods of their restrictions,” according to DiNapoli’s press release.

City probation officers are supposed to check DMV records for license sanctions and vehicle ownership information, to determine which vehicles should have interlocks, according to DiNapoli’s office. Out of a sample of 100 offenders, including 60 repeat offenders, the audit found that in 70 cases no initial DMV check was performed, and 32 offenders were not checked for compliance throughout their entire probation term. Of 22 “high risk” offenders who should have been subject to monthly compliance checks, auditors found evidence of monthly checks in just one case.

The audit also found that NYC drivers circumvent the interlock restriction by driving vehicles owned by other people. “Auditors further found NYC Probation doesn’t always notify the courts or district attorneys when DWI offenders under its supervision are trying to drive while impaired or drunk,” DiNapoli’s office said.

The audit was focused on the NYC Department of Probation and did not examine compliance issues outside the city. DiNapoli’s office says there is an average of 25,000 annual drunk driving convictions statewide, including around 4,000 in NYC. Drunk driving crashes in NYC increased in 2012 and 2013, the audit says, after dipping in 2011.

In response to the audit, the probation department attributed the low interlock installation rate to the prevalence of transit options in NYC. But the only data in the agency’s response is a general accounting of NYC transit mode-share and car ownership rates. The department said it has no jurisdiction to prevent DWI offenders from driving vehicles owned by others, which DiNapoli’s office said points to the need for more stringent monitoring.

The audit recommends city probation officers develop and implement protocols to make sure offenders are using interlocks, and that courts and DAs are notified of violations. With such an abysmal statewide compliance rate, the DMV, Governor Cuomo, and the state legislature need to review penalties to keep drunk drivers off the roads.