There are two main ways that police officers can determine if a driver is impaired. First off, the officer can look for evidence such as the smell of alcohol on the person’s breath, bloodshot eyes, clear evidence of avoidable driving errors and things of this nature. The officer may not know how much the person had to drink, but they can tell that they’re too impaired to drive safely.
However, this is something of a judgment call, so it can be problematic. To get around this, police officers will often use breath tests. If a person is over 0.08%, then the officers are allowed to assume that they are impaired. That is the legal limit that has been established.
But even these breath tests can technically be wrong, meaning that there is no guaranteed way for the police to get a conviction. Why would a breath test be inaccurate?
Department errors
First of all, the police department needs to calibrate the test. If they have not kept proper records or not carried out the calibration at all, the test could be wrong.
Officer errors
Additionally, the officer needs to have the proper training to administer the breath test correctly. He or she also needs to avoid mistakes while giving out that test.
Outside influences
Finally, there are some outside factors that can influence the results of the test. One common example is if a person uses mouthwash that contains alcohol, which could make their results higher than they would be otherwise.
As you can see, drunk driving arrests are not always as straightforward as you may assume. If you are facing charges, you need to know about all of your legal defense options.