Do Ignition Interlocks Have Lasting Effects on Sobriety?

Ignition interlock laws have been around for decades now. While the success of the laws is well known, one sometimes hears an objection to the benefits of installing an ignition interlock, a device which prevents a vehicle from starting if the driver has been drinking.

That objection is that the device has no effect on the driver’s behavior after it is removed — the offender goes back to drinking as before.

The long-term effects of ignition interlock use are still being studied, but there are indications that, in fact, they do play a part in bringing about lower risk drinking habits. Last year a study by researchers at the non-profit Pacific Institute for Research and Evaluation surveyed a group of DUI offenders who were participating in an ignition interlock program.

Before being arrested, all of the offenders drank at bars or restaurants. Afterwards, some continued to drink at commercial establishments, and others confined their drinking to the home.

As it turned out, the offenders who stopped drinking outside (where there was a temptation to drive) also reported that they drank less, drank alone less often, and were more likely to continue to drink less after the interlock was removed.

Another PIRE study found that how often a driver failed a breath test during the interlock program was a good predictor of whether or not the driver was re-arrested for another DUI offense.

While not conclusive proof, these studies do suggest two reasons why ignition interlock programs are useful beyond preventing a driver from operating a vehicle while impaired:

    • Ignition interlocks might well have a lasting effect on drinking behavior
    • Monitoring ignition interlock use might provide valuable predictors of future behavior and suggest helpful ways to intervene with those who struggle

Responsible drinking always involves making sure you find a sober ride home or have a plan to get safely home.