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Types of Evidence in a DUI Case

Elements of a DUI Charge

To be convicted of drunk driving, it must be proven that you were impaired by alcohol or that your blood alcohol concentration was greater than .08 as measured by a chemical test at the time that you were driving. Actual driving is an element of this offense and must be proven. It may be that the police have approached you when you are leaving your car, that you were never seen driving, or that someone else was driving. If the police are investigating an accident, it is their responsibility to show that you were operating the motor vehicle in question.

Officers must try to make and record observations that indicate drunk driving. They may miscalculate, manipulate, or exaggerate patterns in your driving. It may be that the behavior you exhibited should not have caused the officer to stop you in the first place, or it may be that your behavior was not as the officer describes, or didn’t indicate that you were drunk.

Charged with drunk driving? You only have 10 days to save your license! Call (650) 419-2940 or contact us for your free initial consultation with a Bay Area DUI attorney.

About Sobriety Tests

After you have been stopped, an officer who believes you have been driving drunk will try to gather as much evidence against you as possible. There are a number of field sobriety tests that will, if anything, bolster their case against you should you fail a breath or blood test at a later time. People often say that they were persuaded to “walk the line” so as to appease an officer. The reality is that even though police are asking you to perform these tests voluntarily, they know that they can be difficult to perform in any condition, even more so on the side of a busy road while under the stress of an arrest situation.

An officer is likely to attempt other observations of your person and vehicle such as an odor of alcohol, general behavior and appearance, or speech patterns, all of which can be used against you. The officer’s level of experience and attention to procedure can greatly affect the weight of this evidence.

Calculating Your BAC

A device called an intoxilyzer, typically found at a police station, can calculate your blood alcohol content based on a test of your exhaled breath. A chromatograph or blood test can also be used to yield the blood alcohol percentages (.08) that most people are familiar with. Field breath tests are gaining in popularity but perhaps not in reliability and may be refused without penalty.

Blood alcohol concentration is not as easy to measure as police and prosecutors would often suggest. There may be errors in the administration or subsequent handling of these tests that can have an enormous effect on the outcome of a case. A review of the breath test maintenance and calibration records are essential to any defense.

In addition, a retesting of the blood test is imperative to your defense. Usually, these blood tests are very accurate as opposed to breath tests; however, if the blood sample taken by the phlebotomist is improperly preserved and is kept in an improper location, the blood alcohol result can be hugely compromised. A proper defense would check these potential issues and analyze them to your benefit in court or before a jury. Also, if you have any individual or unique medical conditions that would compromise the accuracy of either of these chemical tests, it is imperative that your attorney discover these and use them to your advantage in court with the judge and the district attorney or before a jury.

With an Experienced DUI Lawyer in the Bay Area

Shelley D. Dwyer provides skilled and experienced representation to persons charged with drunk driving. You should act quickly to prevent added expenses and the loss of your driving privileges.

If you are charged with drunk driving or another traffic citation, you will be defending yourself against the police and local authorities who will prosecute you. We believe that, on the whole, these are good people, but when you have already been charged, they are not your friends. It is their duty to mount a case against you and prove beyond a reasonable doubt that the following evidence is in their favor.

If you would like more information about criminal law, please contact the Law Offices of Shelley D. Dwyer by calling (650) 419-2940 and schedule a free initial consultation (usually available the same day), or contact us online. For further general information visit the DUI Information Center.

When Your Freedom Is On the Line,

Contact the Law Offices of Shelley D. Dwyer.
  1. Attorney Dwyer has over 28 years of experience in criminal defense.
  2. We provide vigorous and aggressive defense.
  3. We have handled more than 150 jury trials.
  4. We offer initial consultations free of charge.
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