Breathalyzer Tests
A breathalyzer is a device that attempts to measure a person's BAC (blood alcohol content) 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, while other agencies have shifted to larger and somewhat more accurate breathalyzer machines. With these improvements in technology, breathalyzer test results have become 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 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. Furthermore, 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 0.65 and .09. This significant gap could be all the difference in a DUI case since a reading of 0.65 would also require evidence of impairment, often in the form of field sobriety tests.
Breathalyzer testing machines may also run into other problems when they identify not only ethyl alcohol, but also any other methyl group compound. In other words, a breathalyzer machine may misinterpret other substances in human breath as alcohol content. Some machines have been confused in the past by the presence of acetone, which may be present in unusually high amounts in diabetics and other people with special dietary needs. Fumes from certain paints, adhesives and plastic have also been known to produce false positive breathalyzer tests, while physical activity before a breath test may decrease BAC readings by as much as 25%.
The bottom line is that breathalyzer tests are not always accurate. Thus, if you've been charged with DUI and submitted a breath test, you may still be able to challenge your result. So how you can fight a DUI charge that is presumptive on a breathalyzer test 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 been 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 rebuke 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 but do not believe in the validity of the result, talk to an experienced DUI attorney. Speaking with a qualified DUI lawyer is a great way to assess your situation and determine if any breathalyzer challenges may apply in your case.