For over four years now in California, ignition interlock installations are required after an arrest for driving under the influence of alcohol (even for first-time offenses) if the driver wants to avoid a temporary suspension of his or her license to drive and mandatory for almost all D.U.I. convictions. The ignition interlock law has been heralded as a “win-win.” The law allows a driver to avoid a suspension of driving privileges and makes it near impossible for that driver to drive under the influence of alcohol as long as the device is installed.
But, how effective has the mandatory ignition interlock device (IID) law been in decreasing drunk drivers and more importantly, decreasing the frequency and severity of DUI-related crashes, injuries, and fatalities?
IIDs have been ordered upon the discretion of the court for many years, and in recent years, these installations have become mandatory in many states, as in California. California actually lags in this respect; by 2013, eighteen states had already made IIDs mandatory for all drunk-driving convictions. According to the CDC, IIDs reduce repeat offense driving under the influence of alcohol by 70%….while they are installed. Data gathered from these eighteen states suggest approximately 15% fewer drunk-driving related traffic fatalities in a study published in the American Journal of Public Health. The CDC also cites more recent studies that indicate up to 26% reduction in alcohol-related fatal crashes in states requiring an IID upon conviction of driving under the influence of alcohol.