Four DUI Defenses that May Apply to Your Case

If you’ve had the unpleasant experience of being stopped on suspicion of DUI, you were probably treated like a criminal. Law enforcement officers have a tendency to treat suspects as if they were guilty. But the fact is that there are many legal defenses to DUI charges. Every defendant has the right to present his or her case to the court. Don’t let an officer make you believe you are guilty just because they say you are. At Barnes Law, our experienced Knoxville DUI attorneys know how to defend against DUI charges effectively. Call 865-805-5703 today to schedule your free consultation.

Here are some of the most commonly used legal defenses to impaired driving charges:

Unlawful Traffic Stop

A law enforcement officer must have a valid reason for pulling you over. If not, the stop is not valid, and evidence obtained at that stop is not admissible against you. A simple traffic infraction (such as failing to use a turn signal) can be a valid reason for a stop. An officer can also stop you if he or she has reason to believe you are impaired (such as swerving, driving without headlights at night, or other suspicious driving behavior). But if the officer does not have reasonable suspicion that an offense has occurred, a stop is illegal.

The most important consequence of an illegal stop is that evidence obtained at that stop cannot be used to prosecute you. This is important because almost all evidence of drunk driving will be obtained at a traffic stop. An officer might make observations of slurred speech, bloodshot eyes, the smell of alcohol, or other signs of intoxication. There might be open alcohol containers in the vehicle. Without a valid stop, none of this evidence can be admitted in court. More importantly: if this evidence is used to obtain a search warrant to get a breath or blood sample, that too can become inadmissible. All evidence admitted against you in a criminal prosecution must come from a valid source. If your vehicle is stopped without any legal cause, the evidence obtained at that stop (and any search evidence obtained from that evidence) is not admissible.

Breathalyzer Calibration Errors

A breathalyzer is one of the most common sources of drunk driving evidence. DUI laws across the country have been written in accordance with scientific research, which has found impaired driving to occur when blood alcohol levels reach .08 percent. Juries understand this number. They trust breathalyzers and often assume that the machines are infallible – which is not the case. Like any machine, breathalyzers require maintenance. Manufacturers and law enforcement agencies have maintenance schedules that require officers to check breathalyzers at frequent intervals. The machine must be frequently calibrated against a sample of .08 percent alcohol so that it can accurately determine whether a person is over the legal limit.

Thanks to procedural crime dramas, many people assume that breathalyzers are entirely accurate. Many jurors assume that the machine could not possibly be wrong. This is not the case. The National Motorists Association reports variances of up to fifty percent when comparing breathalyzer tests to blood test results (which are generally acknowledged to be more accurate than breath test results). As a DUI defendant, you have the constitutional right to confront the evidence against you and attack any flaws in the prosecutor’s arguments. An experienced DUI trial attorney can help jurors understand that neither officers nor their equipment work perfectly one hundred percent of the time.

Alternative explanations for signs of intoxication

Many DUI charges are initiated by an officer’s on-scene observations of the defendant. Signs such as bloodshot or watery eyes, slurred speech, unfocused vision, or stumbling are considered to be probable cause to secure a search warrant for the suspect’s blood. But these signs do not necessarily mean that a person is intoxicated. Allergies can also produce bloodshot, watery eyes. A driver’s speech might be slurred because he or she is returning from a dentist appointment. Injuries might prevent the suspect from standing or walking without stumbling. (Certain injuries are, in fact, a reason for officers not to perform field sobriety tests, as the injury can produce inaccurate results.) All of these are explanations for the signs of intoxication that have nothing to do with being drunk. As part of your Sixth Amendment right to confront the evidence against you, you have the right to let an experienced DUI trial attorney present these alternative explanations to a jury.

Forensic lab errors

Like a breathalyzer, a forensic laboratory is not immune from human error. Samples can be mixed up or contaminated. A control sample might not be properly calibrated. Blood might be tested from the first “waste tube” (which contains clotting factors that respond to the initial blood draw and is therefore not used for testing) instead of a later sample that would provide an accurate analysis. These are simple human errors that occur in any laboratory. The public sometimes has the mistaken view that police laboratories cannot make mistakes. The reality is that a lab – whether in a hospital, outpatient clinic, or law enforcement agency – can cause sample errors that lead to inaccurate results. Again, you have the legal right to present this evidence to a jury in order to confront lab results that are being used against you. A jury does not have to accept lab results as accurate just because a prosecutor or police officer says they are.

Call Us Today to Schedule a Free Case Evaluation with a Knoxville DUI Defense Lawyer

As you can see, there are many legal defenses to impaired driving. With the help of an experienced lawyer, you can move to dismiss the charges against you, or effectively persuade a jury of your innocence in order to get an acquittal at trial. You can even challenge a conviction on appeal. There are many legal options, so it is important not to lose hope just because charges have been filed against you. Contact Barnes Law at 865-805-5703 or contact us online today. Our experienced, aggressive DUI attorneys know what it takes to win. They will protect your constitutional rights at every step of the criminal case process.