When you are pulled over and the police officer thinks you are intoxicated, you might be asked to take a breath test. This might be the case if the officer saw you drive in a manner that makes him or her think that you were impaired or if you reek of alcohol when you are pulled over.
If you are asked to take a breath test and know you will pass, you might be in for a surprise. You might still face criminal charges if you pass the breath test. Conversely, even if you fail the breath test, there isn't a guarantee that you will face criminal charges.