Breathalyzer, and Field Sobriety Tests

When a police officer stops a vehicle and suspects the driver of driving under the influence of alcohol or drugs, they may ask the driver to exit out of their car and perform a number of tests to determine the driver’s level of impairment.attorney-handshake

The Breath Test (Breathalyzer Test)

There are two types of breath tests that may be performed. The first is a PBT (preliminary breath test). This test detects the presence of alcohol, but does not measure the amount of alcohol. The results of these tests are generally not admissible in court.

Once the officer determines that probable cause exists for a DUI arrest, the officer will arrest the driver and perform a breathalyzer test. The breathalyzer test will detect the driver’s blood alcohol content (BAC). The legal limit in Utah is .08.

Since the breathalyzer machine is used after an arrest, the key question for a defense attorney is whether or not the police officer had probable cause to make the arrest. If the arrest was not supported by probable cause, the evidence from the breathalyzer test could be suppressed.

Field Sobriety Tests

In the state of Utah, a person is guilty of driving under the influence (DUI) if they have a BAC of .08 or higher, or if they are incapable of safely operating a vehicle. The field sobriety tests serve two purposes for the police. First, they can be used to establish probable cause for an arrest. Second, they can be used to prove driver impairment.

Examples of field sobriety tests (sometimes called roadside tests) include:

  • Eye gaze test (the officer shines a light in your eyes and watches their movement)
  • Walk the line test (walk a straight line, turn, and walk back)
  • Touch finger to nose (to demonstrate balance and coordination)
  • Stand on one foot (to test balance)
  • Alphabet test (to test for slurred speech)

Field sobriety tests are very unreliable. Anyone with a physical impairment or poor coordination could fail these tests even when entirely sober. In addition to challenging the veracity of these tests, I examine the evidence to see if the tests were administered improperly by the investigating officer.

In some cases, police squad cars have dash cameras that may videotape field sobriety tests. Through the process of discovery, I can demand a copy of any dash camera tape if it exists. If a tape is obtained that shows that you performed well on the field sobriety tests, I can use this evidence to strengthen your case.

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