It is commonly understood that a person is innocent until proven guilty when he or she is accused of a crime. This may not seem to be the case, though, when it comes to a DUI arrest. People and courts might assume that an arrest and a breath test are evidence enough of guilt without considering potential innocence. However, according to the United States Department of Transportation, arrest numbers surpass 1.4 million in a single year, so it is worth wondering what fraction of these arrests are falsely made. These are a few reasons this may occur.