What is An IID
(Ignition Interlock Device)

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If you have ever read up on DUI/DWI information, then you have probably heard the term Ignition Interlock Device or Breath Alcohol Ignition Interlock Device. This article is here to help you better understand what these devices are and how they work.

What is An IID (Ignition Interlock Device)

This device, similar to a breathalyzer, checks your blood alcohol level before starting up your car. The IID ties into the car’s ignition system. Before the driver can even start the car, he/she must use the breathalyzer by exhaling into the device to check the alcohol level in his/her system. If the results return greater than the blood alcohol concentration programmed into the device, it prevents the engine from starting.

How Does An Ignition Interlock Device (IID) Work?

If the driver fails to pass the breathalyzer test, the device will interrupt the signal sent from the ignition to the starter. When the IID interrupts the signal, the vehicle will not start. However, if the alcohol level meets the minimal alcohol guidelines programmed into the device, the vehicle will proceed with the normal start-up process.

The IID will require random breathalyzer tests even after the driver passed the original test to ensure the safety of the driver and others. If the driver fails the random breathalyzer test given by the IID or refuses to take the test, the device will log the incident. Then the IID warns the driver and an alarm sounds until the driver turns the ignition off or provides a clean breath sample.

However, many people hold the misconception that the IID will turn the engine off if it detects alcohol. If this were true, manufacturers of the device would be at a high liability. Because turning the engine off could create a very unsafe situation for the driver and others on the road

Ignition Interlock Device Design

Modern IIDs look very similar to normal breathalyzers that police use to check the alcohol level of a driver. IIDs rely on an ethanol fuel cell sensor, which uses a chemical oxidation reaction (COR) to check alcohol levels.

Using COR is the most accurate way to check the alcohol level in the human body. Infrared technology provides a cheaper alternative but it does not give an accurate reading since it is not chemical-specific. The device has its own memory system to keep a log of the driver’s performance.

Authorities can download the log, usually in 30, 60, or 90-day intervals. Periodically, the device will need to be calibrated. The calibration process uses a pressurized alcohol-gas at a recorded alcohol concentration. However, the offender often must pay for the installation, calibration, and maintenance of the device.

IIDS In The Usa And Other Countries

 Many countries currently require the IID by law and more countries adopt this technology every year. In the US, most states now permit judges to order the installation of an IID. However, this is usually for repeat offenders as a condition of probation. In some states, the law requires first offenders to install the device in their vehicle. Politicians in Sweden, Japan, Canada, US, among others have suggested we equip all motor vehicles sold with these devices.

Looking To The Future

The IID technology has a bright future ahead of it. Every year, improvements are made on these devices to provide the best safety needed for the drivers and others. Many countries are considering making the IID standard equipment in all vehicles that are purchased in their country. If a device can be proven to significantly improve safety on the road then that device will be developed through a standard law. In some case, it may even be fully funded by the country that wishes to standardize the technology. 

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