In Georgia, and in most states, the “legal limit” for a driver’s blood or breath alcohol concentration (over the age of 21) is 0.08. Blood/Breath Alcohol Concentration (BAC) is the amount of alcohol in an individual’s bloodstream or breath. BAC is expressed as the amount of ethanol, measured in grams, in 100 milliliters of blood or 210 liters of breath. In order to get a BAC from an individual’s breath, law enforcement agencies throughout Georgia use a machine called the Intoxilyzer 9000 which is manufactured by a company named CMI, Inc. www.alcoholtest.com. This machine is designed to detect the amount of alcohol present in a person’s breath and convert this reading into a numerical alcohol concentration. The machine operator is required to obtain two separate breath samples from the individual. According to Georgia law, “…the readings shall not differ from each other by an alcohol concentration of greater than 0.020 grams and the lower of the two results shall be determinative…” (O.C.G.A. §40-6-392). Therefore, the police officer is only allowed to use the lower of the two readings.
The Intoxilyzer 9000 works by measuring a sample of breath that is passed through a chamber. A beam of infrared light is projected from one end of the chamber to the other. The breath chamber has a filter wheel that spins and is designed to filter out potential contaminants or molecules that can give false readings. If there is any alcohol present in the “deep lung” sample of breath, some of the light energy will be absorbed by the alcohol molecules. The Intoxilyzer 9000 is designed to measure the amount of light energy absorbed by the alcohol molecules and convert this into a numerical BAC reading.
The Georgia Bureau of Investigations (GBI) Division of Forensic Sciences (www.gbi.georgia.gov) is the agency in charge of selecting and supervising the breath testing procedures throughout the state. Even though more sophisticated and accurate breath testing machines are available, the GBI has chosen to continue to use the Intoxilyzer 9000. Unfortunately for Georgia drivers suspected of DUI, the GBI only calibrates these machines once a quarter instead of calibrating the machine before each test as many states require. Additionally, the GBI has decided to use an Intoxilyzer 9000 model that does not have all of the safeguards that are available for the machine. For example, the Georgia version of the Intoxilyzer 9000 does not have the optional equipment that allows a breath sample to be preserved for independent testing. Also, the GBI does not maintain thorough and accurate records of the data the machine generates which greatly diminishes the ability to challenge the accuracy of the machine.