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Seattle DUI Sobriety Testing

When a person is stopped by law enforcement in Washington and they suspect the driver is under the influence, officers have ways of evaluating whether or not this is true. These are called sobriety tests and there are 2 kinds: chemical and physical. Sobriety testing is used to both determine whether or not a DUI arrest should be made and to collect evidence to use against the suspect in court. All drivers should understand what sobriety tests are and whether or not they should consent to taking them.

DUI Field Sobriety Tests In Seattle

A physical test that measures a suspect's impairment is known as a field sobriety test. These tests require a suspect to perform a physical task so that officers can evaluate their movement and their ability to follow instructions. When a driver is impaired by drugs or alcohol, it will often be evident in their motor functions. In 1971, the National Highway Traffic and Safety Administration (NHTSA) did a study to determine what the most accurate field sobriety tests were. They found that 3 tests were best at predicting whether or not a driver was under the influence. These became known as Standardized Field Sobriety Tests (SFSTs) and include the following:

  • The Horizontal Gaze Nystagmus Test: This test is the most scientific of the 3 and requires an officer to wave an object, such as a pen, in front of the suspect's field of vision. The suspect is instructed to follow the object with their eyes only so that the officer can look for signs of nystagmus (involuntary twitching or jerking that occurs in the eyes when alcohol and certain drugs have been consumed).

  • The One Leg Stand Test: This requires the suspect to stand on one foot without using their arms to steady themselves and hold it for 30 seconds while counting out load. The problem with taking this test is that it can be difficult for even a sober person to perform, especially under stress and at the side of the road.

  • The Walk and Turn Test: For this test, the suspect must walk in a straight line touching heel to toe without using their arms to balance themselves and then turn around and walk back. Again, this can be hard for anyone to perform.

While these tests are being performed, police will often be able to record them on video with the dashboard camera installed in many police vehicles. This video can be used as evidence in a DUI case. Suspects do you have the right to refuse taking a field sobriety test with no legal penalty. However, some feel that refusing a test may appear to the police that they have something to hide. This is purely opinion and it is ultimately up to the individual to decide whether or not they would like to take a field sobriety test.

Seattle DUI Chemical Sobriety Testing

The second type of sobriety test is a chemical test. This is a blood, breath or urine test that measures a sample from the suspect to determine whether or not they have alcohol or drugs in the system. Some law enforcement carry a portable breathalyzer device with them so that they can measure DUI suspects' breath, but often a suspect will be arrested and taken to the police station before this test is administered.

Breath tests are the most common type of sobriety test but only measure the suspect for alcohol impairment. In Washington, a driver with a blood alcohol concentration of 0.08 or more is automatically considered to be impaired and can be charged with per se DUI. If a breath test finds that a driver has not consumed alcohol or police believe that they have been taking drugs, a blood or urine test will be performed to determine whether or not the suspect was driving under the influence of drugs. In Washington, a driver has a THC limit of 0.05. Unlike breath tests, which provide results instantly, blood and urine results take several days or weeks to return results.

Under Washington law RCW 46.61.506, drivers have an obligation under implied consent to submit to a chemical test when an officer requests it after being given reasonable suspicion of their impairment. If a suspect refuses to take a blood, breath or urine test, they will be subject to a minimum of 1 year of license suspension.

Seattle DUI Sobriety Testing Information

In DUI cases, often the strongest evidence against the defendant is the results of their sobriety tests. By refusing to take these tests, you are not giving the State any evidence to prove you were impaired while driving. However, you will be charged with violation of implied consent and likely still charged with DUI.

A Seattle DUI attorney can help you fight your charges and understand your rights. Whether you refused a sobriety test or submitted to both field and chemical testing, you still have defense options. Attorney Karimi will work to help you keep your license and get the best results possible. Call our office now for a free consultation.


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If you have been charged with DUI in Seattle or the surrounding area, call The Law Offices of Steve Karimi. He has the skills and the experience to get you the best possible results. Do not trust your future to just anyone, get an experienced professional to defend you.