When a police officer suspects that you have had too much to drink, they will likely ask you to step out of your vehicle for additional screening. In scenarios where a collision has already occurred, they can theoretically demand a chemical test right away.
Otherwise, they may need to engage in preliminary screening to establish probable cause for testing, such as administering field sobriety tests before they ask for a chemical breath test. Even those who believe they did not have too much to drink may feel like they have no choice but to plead guilty if they fail a chemical breath test during a traffic stop.
However, there are numerous situations that could result in inaccurate breath test readings. Reviewing your situation to see if one of these explanations applies could help you prepare a defense strategy.
The device could require maintenance
Analyzing a sample of exhaled air for the presence of certain molecules requires a carefully calibrated device. If the breath test unit used by a police officer has outdated software or has gone months between calibrations, the test results may not be accurate and may therefore not hold up under scrutiny in criminal court.
There could be chemical contamination
Did you just use mouthwash before stepping out your front door on your way to work? Have you recently used an asthma inhaler because you were having trouble breathing due to seasonal allergies? Certain chemicals that you intake before driving or while at the wheel could affect the accuracy of a breath test and lead to a false positive result.
There could be a medical explanation
There are two forms of diabetes. One is genetic and typically starts presenting symptoms in childhood. The other is acquired and often requires diagnosis in adulthood.
Those with type 2 diabetes may not know of their condition and could be in a state of ketoacidosis when an officer pulls them over. Their physical state at the time of the test will result in the exhalation of acetone, which could trigger a false positive. Anyone following a keto-inspired diet could have similar issues. There are other, rarer conditions, that could also cause someone to fail a breath test.
Identifying reasons why you may be able to challenge a chemical breath test could play a role in your defense strategy when facing drunk driving charges.