U.S. Legislation and Studies

Ignition interlock devices are a relatively new form of technology that is designed to keep people who have been convicted of a DUI from driving after they have consumed alcohol.

Since ignition interlock devices have been in use, the Unites States has passed a law requiring those who have been found guilty of driving under the influence DUI to have the device installed as a requirement to have their license reinstated.

Since July of 2004, more than 75,000 ignition interlock devices have been installed in vehicles. These were installed as a result of the Transportation Restoration Act, passed in 1998.

At first, the laws made enforcing the interlock ignition devices ineffective. Drivers would have their license suspended for one year instead of having restricted driving privileges. The device would also have to be installed on all of the cars that they drive, even though they could just have their vehicle titles transferred. There was also no allowance for an employer-exempt vehicle.

Another problem is that although the courts were supposed to order the device’s installation, many judges opposed the installation. Administrative licensing authorities could not mandate that the offender have the device installed.

People could also wait out their suspended license, meaning that they never had to have the device installed.
By the time the law went through the House of Representatives, it was decided that there would be a 45-day hard suspension (meaning no driving at all). After this time, the offender could choose to have the device installed. The interlock restriction is now tied to the driver’s license, rather than to their vehicles.

Do ignition interlock devices keep people from having repeat DUI offenses?

According to a study done by the International Council on Alcohol, Drugs and Traffic Safety (ICADTS), ignition interlock devices, as well as monitoring, led to a 40-95% reduction in conviction rate of people who were previously arrested for DUI. This is important, because the rate of DUI convictions is a good predicator of crash risk involvement.

However, this is not a perfect solution. The device only works when it is on the vehicle. When it is taken off, people may revert back to their old habits. It is also only ordered if the person has had prior DUI convictions – first time offenders are normally not ordered to have the device installed.