When a police officer pulls you over because they suspect you are driving while drunk, they will test your blood alcohol concentration (BAC) using a chemical breath test. Many people think of such tests as the highest possible standard for evidence. People even think they can’t defend themselves against impaired driving charges if there is breath test evidence.
In reality, chemical breath tests are often inaccurate and can lead to innocent people facing serious criminal charges with sometimes lifelong insurance and employment consequences. When might a chemical breath test return inaccurate results?
When the police officer has not maintained or calibrated the device
To return accurate results, a chemical testing unit needs to have updated software. It should undergo regular calibration so that the department can verify the accuracy of test results. If the police department records show that the officer has not calibrated the testing unit, not submitted it for maintenance or not installed software updates, that might make the test results questionable.
When the person taking the test has medical issues
Some common conditions, like diabetes, can affect the accuracy of chemical breath tests. Certain medications, including specific asthma inhalers, can also cause false positives when someone does a breath test. Even your daily diet could impact the accuracy of breath testing.
It’s important that you do not allow the test results to overshadow your own knowledge about what happened before the traffic stop. If you know you only had one drink, insisting on your innocence and questioning the chemical test results makes more sense than questioning your own recollection of the evening. Learning about how chemical breath testing fails can help you find a way to defend yourself against drunk driving charges.