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Using DWI Ignition Interlock Systems

Technology can sometimes be both a curse and a blessing. One piece of technology that seems to be delivering good results is the ignition interlock.

The ignition interlock is a cell phone-sized device that connects to the ignition system of an automobile. Any vehicle with the device won’t start until someone blows into it and the captured breath contains no more than a trace amount of alcohol.

About half of the states, including Minnesota, have laws that require certain people to install the device in their cars. In Minnesota, certain repeat DWI offenders, and first-time DWI arrestees who refuse to take a blood, breath or urine test, or those who score .16 or more on a test, must have the device installed if they wish to keep on driving after their arrest.

Interlock devices can be installed at any authorized service center. Service centers exist within 50 miles of any location in the state. It costs $150 to $200 to install the device. There is an additional charge of $75 per month for its use. State law mandates that companies providing the devices must also have a system in place to make it affordable for indigent people.

Here’s how it works: Once installed, the device won’t let the vehicle start until someone first blows into it. The device then measures the breath sample. If the alcohol concentration is .02 or greater, the car will not start. The device will then force the person to wait five minutes before having another chance to blow into it. The device will not allow a car to start unless a test scores below .02.

Once the car starts, there is also a random rolling re-test. This happens between three and five minutes after the car starts. The driver must pull over and test again. If the person refuses to re-test, the car will keep running but the headlights will flash and the horn will repeatedly honk. Other random tests can occur as the vehicle continues to be operated.

The system also has features built into it to prevent misuse. For example, a camera is mounted inside the car to ensure that the right person is providing the breath sample. A linked computer also keeps a printout of every time a test is taken, every time the car is turned on, and for how long the car was operated.

Is the device necessary? That is a public policy decision. Policy makers are likely aware that in Minnesota approximately 25,000 people were arrested for DWI last year. Additionally, many people die each year in drunken driving crashes. Minnesota law attempts to strike a balance between the public’s need for safety and a family’s need to allow a person to work to support a family. The final decision on where the line should be and how stringent the requirements should be is one properly decided by the other branches of government.

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