How Do Ignition Interlock Devices Work?
Other People Are Reading
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Staring Your Car
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Ignition interlock devices work by measuring the alcohol content on a driver's breath before allowing the driver to start the car. To activate the device, you blow into a cell phone-sized hand-held sensor attached to the car's dashboard. If you blow above a preset limit, the car will not start. The limit is typically a breath alcohol content (BAC) level of .02 or .04.
Rolling Retests
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Ignition interlocks also require you to periodically blow into the machine as you are driving. This prevents a friend from starting the vehicle for you by blowing into the machine and then allowing you to drive off. If you blow above the preset limit, the device will start an alarm and flash your lights. It won't actually stop the vehicle, but it will make it very inconvenient to drive and will alert law enforcement.
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Measuring BAC
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Interlock devices typically use a similar technology to law enforcement breath testing devices. After breathing into the hand-held sensor, your breath passes over and electrical chip. If you have alcohol in your breath, a chemical reaction occurs on the chip, creating an electrical current which is interpreted by the device to determine the BAC of the driver. The higher the BAC, the stronger the current. To be accurate, the interlock must be periodically calibrated.
Cost
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Ignition interlock costs are paid by the offender. Prices vary throughout the nation, but a typical cost is around $75 a month. This covers the installation cost, the monthly maintenance cost and the periodic calibration costs.
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References
- Photo Credit Photo: MADD
