Most DUI cases might seem like open and shut cases. When a police officer makes a traffic stop and the failed field sobriety test is caught on tape, the evidence appears overwhelming. However, no matter how much evidence there is, there is often at least one viable defense to a DUI charge. Below are some of the most common.
Bad Traffic Stop
The constitutional right to be free from unreasonable searches and seizures means that evidence can only be used if it is obtained legally. If the police didn’t have a valid reason for stopping an alleged DUI driver, it doesn’t matter how drunk the driver was. Any evidence of DUI discovered during that traffic stop can’t be used in court.
For a traffic stop to be valid, police need to be able to articulate reasonable suspicion that the driver was under the influence such as they observed the driver swerving multiple times. Or, they can show probable cause that some traffic violation, such as failing to signal a turn, was committed and that gave them a reason to stop the driver. If they can’t do that, the case will probably be dismissed.
Medical Conditions
Medical conditions come in two categories. Physical injuries, such as sprained ankles, or long-term physical disability may affect a person’s ability to successfully complete a field sobriety test. Hopefully, an officer would recognize this and allow the person to complete other tests, but officers sometimes forget common sense or they may not believe that the injury is what’s causing the person to fail the test because they are just below the legal limit and appear to be intoxicated.
Certain illnesses and conditions may also affect a breath test. Breathalyzers estimate how much alcohol is in someone’s blood by measuring how much alcohol is in their breath. Heartburn, acid reflux, and Gastroesophageal Reflux disease are a few examples of conditions that can increase the amount of alcohol in a person’s breath. When that happens, the Breathalyzer may provide a reading that is higher than the person’s actual blood alcohol content.
Miranda Violations
The famous Miranda warnings starting with, “You have the right to remain silent,” must be given before police can ask incriminating questions to someone who is being detained or in custody. If they don’t give the warnings, any statements made in response to those questions can’t be used in court. This means if they ask someone what they’ve had to drink without giving the Miranda warnings, the person’s response that they had eight beers will never be heard by a jury.
Unfortunately, most DUI cases will still give the prosecutor enough evidence to proceed even if a person’s statements are excluded, but each small victory increases the chances of a favorable outcome.
No Probable Cause to Arrest
Police don’t just need a lawful reason to stop a person in the first place. They also must have a lawful reason to keep them in custody. If a person passes a field sobriety test and a breathalyzer test, police can’t arrest them and take them to the station to run a blood test just because the police still think they’re drunk. If they do this, the blood test won’t be admissible no matter what the results are because it was taken in violation of the person’s constitutional rights.
Changing BAC
Blood alcohol levels continuously change as alcohol is absorbed into the body. Prosecutors often use this fact to argue that a person’s BAC was higher when it was finally tested than it was when they were driving.
There’s two sides to this, though. There is also a period of time when BAC is increasing before it reaches its peak. The legal standard for DUI is at the time the person was driving, not at the time the test was administered. If their BAC was below the legal limit when they were driving and then increased to above the legal limit between the time they were stopped and the time police administered the test, no DUI.
Tests Not Administered Properly
Blood and breath tests are complex, and there’s a lot that can go wrong. The machines used need to be regularly calibrated and cleaned. Breath tests must be administered so that a person doesn’t blow for too short or too long a time. Even one deviation from standard procedures could bring the entire test into question.
Mistake of Identity
Identity is rarely a question in DUI cases because most arise out of a traffic stop. DUI charges following an accident are a different story. If police didn’t observe the accident, other evidence, such as eyewitness testimony, will need to establish who was driving. If witnesses have doubts or the evidence placing the driver behind the wheel is highly circumstantial, there might be enough for reasonable doubt.
Falsified Police Reports
Police misconduct is rare, and allegations of police misconduct need to be backed by solid evidence to avoid drawing the ire of the prosecutor and judge. However, it does happen, especially when officers are under high pressure to make a certain number of arrests in a given time period. A person who truly believes they are innocent should at least explore with their attorney whether they can show that police falsified their arrest.