When you are tried for a crime, the only way that you can be convicted is if the prosecutor proves beyond a reasonable doubt that you are guilty. This means if you are in a Nevada court for DUI, you cannot be convicted unless the prosecution builds a strong case against you with solid proof that you are guilty.

In the case of a DUI that proof often hinges on the DUI test that was administered.

These tests are not always reliable though. They are administered by humans so human error can be a factor. The equipment or the test itself can be faulty and mistakes can provide a false reading. When it comes to DUI tests, here’s what you need to know.


Field Sobriety Test

The field sobriety test is the least reliable test that is administered to determine if a person is driving under the influence. It is comprised of several tasks that a police officer has them perform:

  • One-legged stand – Standing with one foot raised
  • Walk and turn – Walking a straight line then turning and walking back in a straight line
  • Horizontal gaze nystagmus – The officer uses their penlight in front of the person’s eyes and moves it back and forth, asking the person to visually track it

There are several factors that can be used as a defense. The first is that the officer approached the test with bias. In other words, he or she administered the test but was already convinced that the person was drunk. They could have also administered it incorrectly. The stress of being stopped and having to perform the test on the side of the road, especially if it is a busy street, can also result in a false positive. Additionally, several medical conditions, medications, and injuries can also cause a false positive.

In Nevada, a person has no legal obligation to take the field sobriety test and due to the high probability of a false positive and the unreliability of the test, it is probably in the best interest of the person to politely decline. However, declining to take the test may result in an arrest.


Blood Test

Nevada DUI cases often use a blood test to measure a person’s blood alcohol concentration (BAC) which must be under 0.08%. Often when a person is arrested for drunk driving, they can choose either a blood test or a breathalyzer test. This is not the case though if the person is suspected of being under the influence of drugs while driving. In that case, a blood test is the only option.

Refusing to submit to a blood test does have consequences. The police can exert physical force to make the person comply with the blood draw. Under Nevada law, police can legally order as many as three blood draws within five hours of the arrest for DUI. If the person refuses to take the blood test, they can lose their driver’s license for one year or even longer – even if the DUI charges are dropped.

A defense for blood draw DUI typically shows that the tests were inaccurate, mishandled, were not given in a timely manner, or were unreliable. There may be others that the defense attorney could introduce.


Breathalyzer Test

The breathalyzer test, or breath test, in Nevada is administered by law enforcement. The person who is accused of the DUI blows into a machine which records their BAC. The test administered at the scene of the stop for the alleged DUI is called a preliminary breath test and that is not admissible in court. Only an evidentiary test is admissible in court and is administered if the person fails the preliminary breath test.

There are several defenses that may be used against the breathalyzer. A defect in the machine is a common defense. The Intoxilyzer 8000 breath testing machine is known to be defective. Medical conditions and even some medications can give a false positive. The defense attorney may also assert that there was a procedural error committed by the police in use of the machine or administration of the test.

Refusal to take the breathalyzer test can result in a one year driver’s license suspension.

Understanding these tests can help you better understand your attorney’s angle in establishing your defense.



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