Virginia drivers who are convicted of driving under the influence of alcohol are required to place an ignition interlock device on their vehicles. However, this is not the case in every state. In some states, the device is only mandatory if a person's blood alcohol is above a certain level, if there is a second offense or at the judge's discretion. In the first study to look at all 50 states and the effect of ignition interlock devices on alcohol-related motor vehicle fatalities, researchers reported a 7 percent decrease in crashes and estimate around 1,250 lives have been saved since the first mandatory laws were passed in 1993.
The study used data from the National Highway Traffic Safety Administration and compared fatalities with state laws about ignition interlock devices. Researchers controlled for general crash trends and other safety laws. The period examined was from 1982 to 2013. With just over half of states requiring ignition interlock devices, researchers expressed hope that the data showing a connection between their mandatory installation and a drop in crashes might encourage more states to follow suit.
Ignition interlock devices work by measuring the breath of drivers before they can start the car. It will not start if they are above a preset limit.
There may be a number of other severe consequences for people convicted of drunk driving. For example, their license could be suspended or they might face jail time. However, it may be possible to get these penalties reduced or to get the case dismissed altogether. For example, a defendant's attorney could challenge the legitimacy of the traffic stop itself.