Although anyone accused of a crime should receive the presumption of innocence, it is unfortunately common for people to make assumptions about someone’s guilt with certain kinds of criminal charges. Driving while intoxicated (DWI) is one such offense. 

Most people understand that police will have performed roadside chemical tests prior to an arrest, which might lead them to assume that those who wind up facing charges are clearly guilty. However, such tests are not always clear-cut evidence of impairments. 

Issues with the testing unit or the individual performing that the test could result in a false positive, as could certain medical conditions in the person facing charges.

Breath test units are not infallible

Chemical breath tests look for a specific kind of molecule in a subject’s breath to determine the likely presence of alcohol in their body. Depending on the number of molecules and the volume of the exhaled air tested, the testing unit can estimate the likely blood alcohol concentration of the person undergoing the test. 

Still, these tests are not infallible. All kinds of issues could compromise the validity of the test results. An officer who administers the test improperly due to outdated information or methods is one such issue. It could also be possible for issues with calibration or outdated software to impact the performance of the unit. 

Reviewing the certification records for the officer performing the test and the calibration and software records for the testing unit can be a first step toward challenging the results of the breath test in your drunk driving case. Find out more about your legal options today.