San Luis Obispo DUI Attorney Drunk Driving DMV Hearing Lawyer

Breathalyzers

A breathalyzer is a machine used by law enforcement to determine the blood alcohol concentration (BAC) of a driver suspected of driving under the influence. They measure the amount of alcohol in a person’s breath.

The word breathalyzer is the brand name of a group of machines made by a specific manufacture, but it has come to be the generic term used for all breath analyzer devices. The National Highway Traffic Safety Administration (NHTSA) maintains a list of approved devices.

There are desktop breathalyzers and there are portable hand-held devices. You would most likely find a desktop breathalyzer in a police station and find portable hand-held devices with officers in the field. The basic principle of why a breathalyzer works is alcohol is detectable in the breath since it gets absorbed into the bloodstream from the mouth, throat, stomach, and intestines. Once inside the bloodstream alcohol travels throughout the body, including the lungs. Inside the lungs, the alcohol mixes with the air an individual is exhaling. As the person exhales, the breathalyzer can measure the alcohol. Alcohol is identifiable in the breath is because it is not digested upon absorption and it does not change chemically in the bloodstream. Therefore, it is believed an individual’s breath alcohol concentration relates to their blood alcohol concentration.

The suspected driver exhales a measured amount of breath into a breathalyzer to have their BAC measured. The machine calculates the BAC based on the ratio of alcohol in the blood to the breath. The ratio of breath alcohol to blood alcohol is 2,100:1 – meaning that 2,1000 milliliters of air exhaled from the lungs will contain the same amount of alcohol as 1 milliliter of blood. If a breathalyzer registers a driver’s BAC at 0.08% it means there is 0.08 grams of alcohol present per 100 milliliters of blood. The law states it is illegal to operate a motor vehicle with a BAC of 0.08% or higher.

There are many problems with using a breathalyzer as a test for arresting a suspected drunk driver. One problem is the sample tested to determine a driver’s BAC is there is no way to verify the results. There is no way to save the breath used for the test and confirm the results the officer got at the time of the arrest.

Another issue is the breathalyzer does not actually test blood alcohol, it estimates it. The larger desktop devices tend to have better results than the hand-held devices law enforcement often carries.

The calibration of the device is critical for accurate results. Improper calibration can give inaccurate readings.

An experienced DUI lawyer will have the strategies to challenge the results from a breathalyzer.

Home » Police Evidence » Breathalyzers