DUI Evidence

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What types of Evidence are considered in a DUI Case?

Drunk driving, or driving under the influence (DUI), is a criminal offense according to various federal and state laws.  DUI is usually defined as operating a motor vehicle while having a blood alcohol concentration of 0.08 or above.  DUI laws may also prescribe penalties for persons who drive while impaired by any drug or alcohol, even prescription medicines. 

When a DUI case is heard in court, the judge or jury may consider various types of evidence that are related to the defendant’s level of intoxication while driving.  Most evidence in a DUI case is gathered at the point of arrest and is called “field evidence”.  In general, field evidence in a DUI case falls into five basic categories:

Thus, prosecutors often analyze a variety of factors when determining guilt in DUI case.  Of course, one of the main items of evidence is the result of breathalyzer tests, or blood or urine samples from a field sobriety test. 

A person’s blood alcohol level at the time of arrest can sometimes lead to charges of “per se intoxication”.  Per se intoxication means that the person is automatically deemed to be drunk driving if their blood alcohol content is above the state limit (0.08 in most states).  They may be prosecuted regardless of how little their driving may be affected.   

How do Police Officers determine whether a person is Intoxicated?

In order to arrest a suspect for DUI, a police officer must first have reasonable suspicion to pull the car over and begin questioning the driver.  If they suspect that the driver is drunk, they may conduct a field sobriety test which tests the driver’s motor skills.  For example, the police may require the driver to recite a portion of the alphabet backwards.   

Intoxication is usually confirmed through the use of a breathalyzer device.  However, some states allow a police officer to conclude that a person is intoxicated based on their conduct or appearance.  Some common symptoms of alcohol intoxication that police look for are:

If a police officer notes any of these symptoms, they will usually make a written report that describes the conduct and appearance of the defendant.  The report may then be used as evidence at a later time in court. 

At times these symptoms can be even more incriminating than blood alcohol level readings.  Alcohol affects every person differently- a person who has had only a small amount to drink already be physically impaired even if they are within the state limit for blood alcohol concentration.   

Do I need a Lawyer if I have issues with Evidence in a DUI Case?

DUI laws are an important part of maintaining highway safety.  If you have concerns regarding the evidence used in your DUI case, you may wish to consult with a lawyer for advice.  Some areas of evidence law can be very technical and nature, and are best addressed through the expertise of an attorney.  It is especially important to consult with a lawyer if the DUI charges involve serious injury or bodily harm to another person.  

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Last Modified: 03-31-2011 04:17 PM PDT

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