Challenging Field Sobriety Tests and DUIs in Tacoma WA

By James J. White 4/3/23

A Tacoma DUI Police Officer’s decision to arrest for DUI is often based on how a suspect performs on Field Sobriety Tests (FSTs). FSTs are a series of physical and cognitive tests that law enforcement officers use to determine if a driver is under the influence of alcohol or drugs. These tests are typically administered during a traffic stop and include tasks such as standing on one leg, walking a straight line, and following a stimulus, like a pen or finger, with your eyes. While FSTs are commonly used to determine if someone is driving under the influence, they are not always accurate and can produce false positives. Despite their prolific use, no statutes or administrative codes regulate the administration of field sobriety tests.

One reason why FSTs may not be accurate is that they are subjective. The results of FSTs are often based on the observations and opinions of the law enforcement officer administering the tests. This means that the accuracy of the results can be influenced by the officer's personal biases, level of training, and experience. Additionally, the FSTs themselves are not standardized, meaning that there is no universal set of criteria for administering or interpreting the tests. As a result, the accuracy and reliability of FSTs can vary widely from case to case.

Another factor that can impact the accuracy of FSTs is the physical and mental condition of the person being tested. FSTs require a significant amount of physical coordination, balance, and cognitive function, which can be impaired by a variety of factors. For example, someone who has a medical condition that affects their balance or cognitive abilities may perform poorly on FSTs even if they are not under the influence of alcohol or drugs. Similarly, someone who is nervous or anxious during a traffic stop may also perform poorly on FSTs, even if they are not impaired.

Furthermore, FSTs can produce false positives in cases where a driver is not under the influence of alcohol or drugs. For example, the "horizontal gaze nystagmus" test, which involves following a stimulus, like a pen or finger, with your eyes, is often used as an indicator of alcohol or drug impairment. However, nystagmus can also be caused by other factors, such as fatigue or certain medical conditions. As a result, a driver who performs poorly on the nystagmus test may be falsely accused of driving under the influence.

Another problem with FSTs is that they are often administered under stressful and distracting conditions. During a traffic stop, the driver may be nervous, frightened, or distracted by the presence of law enforcement officers, traffic, or other factors. These distractions and stressors can make it difficult for a driver to perform well on FSTs, even if they are not under the influence of alcohol or drugs.

Finally, FSTs are often used in combination with other forms of evidence, such as Breathalyzer tests or blood tests. However, these tests are not always accurate either. Breathalyzer tests, for example, can produce false positives due to a variety of factors, such as mouth alcohol or the presence of interfering substances. Blood tests, while considered to be the most accurate way to determine blood alcohol concentration (BAC), can also produce inaccurate results due to mishandling, contamination, or improper analysis.

In conclusion, FSTs are not always accurate and can produce false positives in cases where a driver is not under the influence of alcohol or drugs. The subjective nature of FSTs, combined with the physical and mental condition of the driver, the distracting and stressful conditions of a traffic stop, and the potential for false positives in other forms of evidence, can all impact the accuracy and reliability of FSTs. As a result, it is important for anyone facing DUI charges to work with an experienced Tacoma DUI defense attorney who can challenge the validity of FSTs and other forms of evidence in court.