For most drivers, the legal limit for blood alcohol concentration (BAC) is 0.08%. It is possible for someone who has a lower BAC to be cited for impaired driving if they exhibit signs of being under the influence of alcohol or other substances. But the legal limit is still important because the court can presume that someone was impaired if they have broken that limit.
As such, breath tests are often used as evidence in court. An officer may see a driver make a mistake that gives them reasonable cause for a traffic stop. That officer may then ask the driver to go through field sobriety tests, which they may fail. The next step may be giving them a breathalyzer to check their BAC. But for as often as these tests are used as evidence, there are a few key reasons why their results could be wrong.
First and foremost, police officers can make mistakes when administering a test. Perhaps a officer lacked training or was never trained at all. Maybe it was their first time ever using a breath test device on their own. If they made a critical mistake, the results could be wrong.
Maintenance and calibration issues
On top of that, breath tests require regular maintenance and calibration. If there are no records that this actually happened, a breath test may not be functioning properly, but no one would know. A neglected breath test could also provide inaccurate results.
Not an approved device
Furthermore, it’s very important that police officers only use officially recognized devices that are on a specifical approval list. Aftermarket devices or consumer model devices are not allowed.
In some cases, a person may have alcohol in their mouth that makes a breath test give a drastically higher reading than is accurate. This could happen if someone had just use mouthwash, for example, or if they burp while taking their breath test.
These are just a few examples of how a test could be wrong, though every case is unique. It doesn’t take much inaccuracy to move someone up over the legal limit. As such, anyone facing drunk driving charges need to know exactly what legal options they have available by seeking legal guidance promptly.