How does my car breathalyzer detect alcohol?

People sometimes question the accuracy of a car breathalyzer system, also known as an ignition interlock device. They wonder how a breath sample can reveal the amount of alcohol in a person’s system. However, ignition interlocks provide accurate measurements that prevent drunk drivers from starting and driving their car when alcohol is present in the body.

How the Body Processes Alcohol

When you drink alcohol, it enters your stomach where it is absorbed throughout your body, including your blood stream. As the body processes the alcohol, it exits in one of three ways: through the kidneys during urination, through the liver as it breaks down alcohol, and through the lungs when exhaling. An ignition interlock device detects the amount of alcohol in your breath when you dispel air from your lungs. But how is the device able to measure the amount of alcohol in your breath?

Fuel Cell Technology

For more than 30 years, Intoxalock has been a leading provider of ignition interlock devices. In fact, our company was a pioneer in developing the technology used in most ignition interlocks. Using fuel cells, our device uses an electromechanical process which measures the presence of alcohol molecules in your breath sample.

As your breath passes through the fuel cell, platinum electrodes within the device oxidize any alcohol present, producing acetic acid, protons and electrons. The alcohol produced electrons will give off an electric current which stimulate the electrodes in the device. The strength of this current corresponds to the volume of alcohol present in your breath sample, indicating your BrAC level.  

Starting the Vehicle with an IID

If your BrAC is within legal limits, the device will “communicate” with your vehicle, allowing you to start the ignition. However, if your BrAC measures too high, the device will prevent your vehicle from starting.

Technology and Accuracy

Fuel cell technology has proven to be more accurate than other types of ignition interlock technology because it produces consistent, reliable results time after time. Fuel cell technology is able to accurately read Breath Alcohol Content (BrAC) and requires fewer calibrations than devices that use other technology, such as semiconductor models.

We Can Help

Intoxalock offers three ignition interlock models that are easy to use and feature fuel cell technology, single-button activation, LED screen and guaranteed accuracy. We also provide models that offer real-time reporting, camera photo verification and more to meet ignition interlock requirements for your specific state. For questions about devices, how to get started or where to install a device, call a 24/7 customer service representative at 833-623-0200.