Calling the evidence into question could be a sound strategy. A law enforcement officer is not allowed to make a traffic stop on a whim. There must be a reasonable justification for doing so. For DUI cases, the officer might suggest that the driver was unable to maintain a lane, drove over the speed limit or was operating the vehicle erratically. Still, if there was no legal reason to make the stop, this could nullify any evidence like a breath test and other procedures to gauge a driver’s blood-alcohol content (BAC).
After a traffic stop, the officer may ask the driver to take part in field sobriety tests. These include the one-leg stand test, the walk-and-turn test and checking the driver’s eyes in a horizontal gaze nystagmus test. There could be underlying factors rendering them inaccurate. The HGN test could be problematic due to a health issue; the ground might have been uneven rendering the other tests unfair; or the officer could have been unclear with instructions.
A breathalyzer machine must be properly calibrated and have regular maintenance. Failure to do so could inhibit its accuracy. Storing blood in an improper way could result in inaccuracies. The person arrested might not even have been driving. Having legal advice from the beginning is a fundamental aspect of a defense. Contacting a law firm that understands criminal defense and how to call charges into question may help with achieving a positive outcome.