Ignition Interlock Device

Drunk Driving & DWI conviction

Ignition Interlock Device: How They Work, Why They Are Used and When Are They Used

Ignition Interlock Device – This is an instrument that’s been designed to keep somebody who has been drinking from operating a vehicle if the device discovers there is alcohol on the operator’s breath. Most states have some DUI law that allows judges to place these devices in vehicles that DUI offenders drive.

Now, each state law on the ignition interlock device varies. So, you should review your state’s DUI laws concerning the ignition interlock device and if it’s a state mandate or up to the judge.

Ignition Interlock Device

How Does The Ignition Interlock Device Work

This device works to get a measurement of driver’s blood alcohol content (BAC). If the device determines that the driver has alcohol on his/her breath, it’ll deactivate the ignition, which will keep the vehicle from starting. It stays lock until the ignition interlock device finds little to no alcohol on the driver’s breath. The period of lockout will increase for each failed test.

When doing rolling retests, most devices need a brand new fresh breath test. If, in that time period the machine has not gotten that clean breath, an alarm will sound and the vehicle horn will begin honking. This tells the driver to turn off the vehicle.

The ignition interlock device will not shut off the vehicle if the driver doesn’t pass the test especially if it’s moving. And, some ignition interlock devices will record the information about the repeat failed test.

Optional Ignition Interlock Device Laws: What Judges May or May Not Do To DUI offenders

Several states permit judges to choose if a DUI offender’s vehicle should be equipped with an ignition interlock device after a DUI conviction, under the DUI criminal charge. Some laws state that the devices may be placed on vehicles where the person has a suspended driver’s license.  For these circumstances, the qualified offenders must meet several other sentencing requirements so they’ll be able to drive with it on the vehicle. These include:

- Alcohol treatment program
- Driver’s license suspension
- Fines
- Jail time
- Probation

State Ordered Ignition Interlock Devices

An increasing number of states are deciding on the issue of making ignition interlock devices mandatory rather than letting judges to decide whether or not offenders need them. The most common situations states demand the device be installed are:

- A child was in the vehicle at the time of the event
- Offenders are repeat DUI offenders
- The BAC level was extremely high

The Costs Associated With The Ignition Interlock Device

States have rules that lay out the terms of the device’s installation and inspection. State approved installers must place the device in the vehicle, which the offender must proof to the court was done. Inspections must be done every so often by a state-approved installer. This proof must also be sent to the court.

Yes, DUI offenders must pay fees that are associated with the ignition interlock device. These fees include:

- Installation
- Calibrating
- Security deposit/insurance
- Payment for device

Some states will reduce the DUI fines to assist those folks who are unable to purchase the unit.


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