The Roadside Breathalyzer - An Inaccurate Test

A person suspected of driving under the influence (DUI) in Georgia is very often given two breathalyzer tests by police officers. The first test is given on the side of the road after you have been pulled over and may be done in conjunction with other field sobriety tests. The second test is performed back at the police station.

Roadside breathalyzer tests are notoriously inaccurate, and in some cases, the results from them can be challenged to lessen your charges or even have them dismissed. An experienced Cobb County DUI attorney can guide you through the DUI process and fight your charges.

The Preliminary Breath Test

First, it is important to understand the legal difference between the Preliminary Breath Test and the official chemical test which are part of Georgia's implied consent laws. The preliminary breath test is conducted during the traffic stop by way of a handheld device. This device is commonly called an Alco-Sensor.

The chemical test is given at the police station and is done with the Intoxilyzer 9000. If you refuse to take the chemical test at the police station, you can face automatic suspension of your driver's license along with other penalties.

However, you are NOT obligated to take the preliminary breath test. You may refuse the roadside breath test without facing legal penalties. (TIP: Refuse politely.)

Inaccuracy of Preliminary Breath Test

Breathalyzers can be inaccurate for a number of reasons, and this is especially true of handheld devices. Below are some of the most common reasons for breathalyzer test inaccuracy.

Improper Calibration

Handheld breath tests must be calibrated on a regular basis. This requires a trained technician to check the accuracy of the device by running a solution with a known alcohol concentration through it. Georgia has specific laws which state how often devices must be calibrated, and which models of handheld devices are permissible.

Partition Ratios

Handheld devices measure blood alcohol concentration (BAC) by estimating breath alcohol. They do this by multiplying the breath alcohol measurement by a "partition ratio." The issue with this system is that different people have different partition ratios, which can be affected by a driver's gender, weight, body temperature, and more.

Radio Frequency Interference

Radio waves from police radios and other sources can disrupt the test and cause inaccuracies

Other Sources of Mouth Alcohol

Handheld devices often cannot tell the difference between alcohol found in beer or liquor from other non-intoxicating sources such as mouthwash, certain mints, or breath sprays. The test may also display an inaccurately high number if you have recently burped or vomited immediately preceding the test. Officers are supposed to employ a "deprivation period" in which they wait at least fifteen minutes before administering the test.

Margin of Error

Every breathalyzer has a margin of error. This means that the results of the test are expected to be inaccurate to a certain point. For example, a handheld breathalyzer may have a margin of error of 0.02%. If a breathalyzer measures your BAC at 0.09% (above the legal limit) it could actually be as low as 0.07% (below the legal limit).

Challenging Your Results

Remember that you are NOT required to consent to the roadside breathalyzer test. If you did consent to the roadside test, a highly experienced Cobb County DUI attorney can challenge the results of your test. Contact us today for your free consultation.