There are two things wrong here. The first is that no one is presumed guilty until proven innocent — it is the other way around. And the other thing is that there are actually many ways that someone can be cleared of wrongdoing in a DUI case. So if you have been hurt in a drunk driving accident, this information is important to realize. Your case may not be a slam dunk.
For example, some people may be wrongfully accused of a DUI depending upon the circumstances. Maybe they were forced to drive drunk under the threat of injury or force; or maybe there was a medical emergency that involved themselves or a friend, requiring them to drive under the influence in order to save a life; or maybe the person was entrapped by a police officer or became intoxicated in an involuntary fashion (someone spikes a person’s drink without their knowledge).
There are also procedural reasons why a DUI charge may be thrown out. What if the initial stop was improper? What if the police officer botched a breath test or handled the evidence improperly? What if the chain of custody for urine or blood, which could establish a person’s BAC, was improper? What if the evidence itself was tainted during testing or at some point during the transfer of custody of the evidence?
Source: FindLaw, “Defenses to Drunk Driving,” Accessed June 23, 2016