A breathalyzer is a device that attempts to measure a person's blood alcohol content (BAC) via a sample from the breath.
Law enforcement officials most commonly administer breathalyzer tests with portable roadside units that are now considered to be reliable enough to be admitted as evidence in DUI cases. Breathalyzer test results have evolved into the most common and powerful evidence in drunk driving cases.
It is currently a crime in every state to operate a vehicle with a blood alcohol level of 0.08 percent or greater.
If the breathalyzer test is considered reliable and admissible, a reading of 0.08 or higher is considered presumptive evidence of DUI. In other words, the burden of proof shifts to the defendant as he/she must disprove the accuracy of the breathalyzer test.
Challenging breathalyzer results is possible, as these tests are often based on assumptions that do not apply to everyone. To begin with, many breathalyzers assume that the tested individual is an "average" person and do not take into account sex, height, weight, metabolism and whether that person has just eaten.
Many breathalyzer tests assume a specific ratio (2100:1) between BAC and breath alcohol content in order to make its conversions.
As this actual ratio for a particular individual may vary between 1700:1 and 2400:1, a reading of 0.08 could actually mean a blood alcohol content of between 0.065 and .09. This significant gap could be all the difference in a DUI case since a reading of 0.065 would also require evidence of impairment, often in the form of field sobriety tests.
The bottom line is that breathalyzer tests are not always accurate. Thus, if you've been charged with a DUI and submitted to a breath test, you may still be able to challenge your result.
You may be able to refute a breathalyzer test by showing that you're not the "average" person and that the standard formulas of conversion do not apply. You may also submit new evidence that you've been recently exposed to chemical compounds containing alcohol that adversely affected your BAC level, or even contest that your breath sample was handled improperly or the breathalyzer was not working correctly.
In some states, you may demand an independent test of your breath sample, which may counter the presumption of DUI if it delivers results that are greatly different from the original breathalyzer test.
If you've been charged with DUI and failed a breathalyzer test , talk to a DUI attorney. Speaking with a qualified DUI lawyer is a great way to assess your situation and determine if any breathalyzer challenges may be applicable in your case. The DUI attorneys in the Total Lawyers network are available to assist you. To speak with a DUI lawyer in your area, complete our online DUI case evaluation form or call us at 877-421-3761.