How Effective is the Ignition Interlock Device in Preventing Drunk Driving?

Over the past few decades there have been many preventive measures implemented to reduce the risks of drunk driving. The courts and motor vehicle departments have used traditional countermeasures such as fines, jail terms, and license suspensions to control drunk driving offenders. Now there are instruments like the ignition interlock device (IID) that are being used as punishment. However, the question that lawmakers have been asking is: How effective is the IID? Has it indeed lowered the reoccurrences of drunk driving in repeat offenders?

IIDs are instruments installed in automobiles that measure the alcohol on a driver’s breath. The driver provides a breath sample and if the IID detects alcohol, the car will not start. IIDs were developed and have been researched since the 1960s, however, it wasn’t until recently that these instruments have been used and accepted by the courts. California was the first state to enact legislation that authorized judges to order DUI offenders to install IIDs. California was also the first state in which the ignition interlock program was evaluated.

There have been a few studies in various states to determine whether or not IIDs are effective in reducing DUIs. The results of these studies have been mixed, although most of the results suggested that IIDs have reduced DUI reoccurrences in offenders. That’s only if the instrument remains in the car. However, once the IID is removed from the car, the chances of another DUI incident occurring goes back up. This suggests that IIDs are not going to actually change people’s behavior. It only prevents them from driving their own car when they’re drunk. They’re going to continue to drink whether or not the instrument is installed.

In September 2005 a study released by the Department of Motor Vehicles (DMV) in California concluded that IIDs can be effective at reducing the occurrence of subsequent DUIs. Unfortunately, judges have not always ordered DUI offenders to install an IID in their car. Technically, the IID is effective, but it’s the actual program that is not effective.

Based on the results of this September 2005 study, the researchers offered these recommendations to improve the program:

1. An improved monitoring system for DUI offenders ordered by judges to install an IID. It’s important for the courts to be consistent because installing the device does have a significant effect in reducing DUIs.

2. Allow second DUI offenders the chance to reinstate their driver’s license if they install the IID in their vehicle. This gives repeat offenders incentive to put in the device if the court does not mandate it. Another way to encourage offenders to install an IID is to reduce the period of license suspension.

3. Impound the vehicle of a person who is caught without an IID in their car. This applies to those people restricted to driving an IID-equipped vehicle.

4. Investigate the barriers to the use of the IID and find more effective programs to implement these devices. The DMV should have the responsibility of leading this task force and finding the resources to fund it.

5. Do not emphasize the use of the IID for first-time offenders. Currently there is no evidence that the device is effective at reducing the reoccurrence of a DUI in first-time offenders.

6. Continue to support the law that requires judges to order DUI offenders to install the IID in their vehicle.

The ignition interlock device is not going to be the key to completely wipe out drunk driving. However, preventative measures combined with consistent action is a step in the right direction.