The Breathalyzer

If a driver has been arrested for driving while intoxicated (DWI) in New York and taken to the police station for booking, the driver will be asked to submit to a breath test by blowing into a device commonly known as the breathalyzer. If the driver is unwilling to take the breathalyzer, the driver will be deemed to have "refused" the test. If there is a refusal, the driver will be noticed by the Department of Motor Vehicles (DMV) to appear for a Refusal Hearing before an Administrative Law Judge (ALJ). If the ALJ finds that the driver refused to take the breathalyzer, the driver will encounter additional penalties from the DMV other than the potential penalties stemming from the arrest. DMV penalties include revocation of the driver's license, civil penalties, and other administrative fees. Although, the term breathalyzer is commonly used to describe all breath testing machines, today, police agencies generally no longer use the the actual chemical testing device called the Breathalyzer, they use devices that employ infrared spectroscopy. Commonly used devices include the Alcotest, BAC Datamaster, and the Intoxilyzer.

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The Alcotest is used to measure a drunk driving suspect’s blood alcohol content. The Alcotest 7110 MKIII-C does this by actually taking two separate breath samples and sends those samples one at a time through the machine’s two testing chambers. The first chamber analyzes alcohol contained in the breath sample by using a chemical reaction from an electrochemical cell (referred to as the EC result). Next the machine sends the same breath sample into a second chamber where it is tested using infrared lights called infrared spectroscopy (referred to as the IR result). Once the IR result is completed the machine purges itself of the air sample and gets ready for the second breath sample from the suspect. This will ultimately result in 4 BAC readings – 2 EC results and 2 IR results. This system which uses two separate and accurate technologies to test the same breath sample is intended to provide the highest level of accuracy and legal integrity. In order for the machine to give a successful final BAC, all 4 readings must be within a certain tolerance of one another to be considered a “true” reading. This is done by plugging the numbers into an algorithm and producing a single result.

The Datamaster is used to measure a drunk driver's BAC. The BAC DataMaster is a breath testing machine which uses only infrared spectrophotometry. Many vapors, including ethanol in the breath, absorb infrared energy. The machine captures a breath sample in its testing chamber and sends a beam of infrared energy through the sample. When infrared energy passes through the ethanol molecule, the molecule begins to vibrate. The machine employs a detector to detect vibrations in the known ethanol micron ranges. The machine works to filter out frequencies that are not

The Intoxilyzer is used to measure a drunk driver's BAC. The Intoxilyzer, like the datamaster, uses only infrared spectrophotometry by exposing air in a sample chamber to infrared light. An emitter produces a known amount of infrared light which passes through the sample chamber to reach a sensor at the opposite end. Alcohol molecules are known to absorb a certain amount of infrared radiation and so, if alcohol is in the sample chamber, a predictable proportion of the light will not reach the sensor. The machine compares the light sent with the light received in order to calculate an alcohol concentration. The more infrared radiation is absorbed, the more alcohol is in the breath sample.

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Alcotest 7110 MKIII

BAC DataMaster

The Intoxilyzer

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