Legal Professional?
Build Your Business

DUI DWI Defenses



If you have been arrested for drunk driving-commonly referred to as DUI and DWI-and plead not guilty, your case will advance to trial. During this trial stage, you and your DUI attorney will have the opportunity to establish a DUI defense.

A DUI defense is the argument you make to try to convince the jury you are not guilty of drinking and driving or that there is not enough evidence to establish beyond a reasonable doubt that you were drinking and driving. There are a number of DUI defenses you can choose from. Which one you and your attorney decide to use will depend on a number of factors including the laws of your state, the circumstances of your arrest, and your DUI record.

Driving Observation DUI Defense

A police officer has the right to pull you over for a number of reasons. The officer can pull you over for a traffic violation, such as crashing a red light, he or she can pull you over at a sobriety checkpoint, or you can be pulled over on suspicion of drunk driving.

To pull someone over on suspicion of drunk driving, the driver must exhibit some type of abnormal behavior. For example:

  • Weaving
  • Taking up multiple lanes
  • Driving too slowly
  • Hesitating before going through a green light

At trial, the prosecution will rely on the police officer's testimony about your behavior. Your attorney may argue the DUI defense that there are other reasons beside intoxication that could lead to this type of behavior.

For example, you may have been tired or on medication. Although your erratic driving may have constituted a traffic violation, that does not automatically mean you are guilty of committing DUI.

Behavior Observation DUI Defense

The prosecution will also usually ask the arresting officer to testify about your behavior at the time of your arrest. The office may say you exhibited one of the following signs:

  • Bloodshot eyes
  • Slurred speech
  • Pupil enlargement
  • A lack of balance
  • Unintelligible speech

Once again, however, this kind of behavior could be caused by a number of factors. Your DUI attorney could assert the DUI defense that something else contributed to your actions, such as:

  • Fatigue
  • Contact lenses
  • Illness
  • Stress
  • A disability

These same defenses can be used if you fail a field sobriety test. Field sobriety tests include standing on one leg, walking a straight line, and following an object with your eyes without moving your head. If you fail a field sobriety test, the officer has established probable cause and can arrest you. Probable cause means the officer has a good reason to believe you have committed DUI.

Blood-Alcohol Level DUI Defense

Besides submitting to field sobriety tests, a police officer may also have you take a breathalyzer test. A breathalyzer test provides an estimate of your blood-alcohol level based on the amount of alcohol in your breath. If your blood-alcohol level is at .08 or above, then you will be arrested for DUI.

However, breathalyzer devices are not perfect. This means your attorney may have the opportunity to assert a blood-alcohol level DUI defense.

Some breathalyzers require periodic calibration. If the device was not calibrated for some time, your reading may have been incorrect. Your attorney can subpoena records on how the breathalyzer device operates and how the police maintain it. Your DUI lawyer may also bring in an expert to testify about the unreliability of the device.

In addition, a number of other factors can result in false breathalyzer readings. Some medical conditions, such as diabetes, can cause certain breathalyzer devices to show an inflated blood-alcohol level. If you had just been drinking shortly before being pulled over, the alcohol content in your mouth can provide a much higher reading than your actual blood-alcohol level.

The most important thing you can do to help your case if you are charged with a DUI is to exercise your constitutional right to hire a DWI attorney as soon as possible. The sooner you can contact an attorney, the sooner the two of you can develop a DUI defense strategy.