Courts don’t accept every breath test result. In a DUI case, the law sets clear rules for how officers must handle and present those results. When they break those rules, the court can strike the evidence. Here are three reasons that can happen.
The officer didn’t follow the required observation period
If the officer didn’t watch you for the full 15 minutes before giving the test, that’s a problem. The law requires them to observe you continuously during that window to make sure you didn’t burp, vomit or leave anything behind in your mouth that could throw the reading off.
If they’re distracted, checking their phone or walking away during that time, the defense can argue that the result doesn’t hold up. Most people have no idea this rule even exists until it’s too late, but in court, it can be a make-or-break detail.
The machine wasn’t properly calibrated or maintained
Breathalyzer results only matter if the machine was working like it’s supposed to, and that means regular, documented maintenance. If the police can’t show calibration records for the device used or if the records reveal missed service dates, bad test results or inconsistent readings from other cases, your attorney can move to suppress the entire test. These devices are sensitive and highly regulated, so even small gaps in maintenance or verification can become grounds to challenge their accuracy.
The person doing the test lacked proper training or certification
Most states require that officers keep their certification current and complete training specific to the equipment in use. If the paperwork is missing or expired, the breath result may be excluded entirely. This isn’t a technicality; it’s a legal safeguard meant to ensure only trained personnel handle forensic evidence that can put someone’s license, job or freedom on the line.
Fight for your freedom
Breath results aren’t immune to scrutiny, and courts do throw them out when protocol gets skipped or evidence doesn’t add up. If you’re facing DUI charges and the breath test feels like a done deal, it’s worth slowing down and asking whether the evidence actually meets legal standards. When it doesn’t, that opens the door to a very different outcome.