If you’re ever pulled over for suspicion of impaired driving, the police officer may ask you to take a series of field sobriety tests. Your first instinct may be to comply with their request, especially if you’re sober.
However, doing so may have unintended consequences. Let’s look at a few.
Subject to interpretation
Missouri has implied consent laws, meaning that by operating a vehicle, you automatically agree to submit to a chemical test to determine your blood alcohol concentration (BAC) if the officer has a reasonable belief that you were driving impaired. This implied consent doesn’t extend to field sobriety tests.
These tests were developed by the National Highway Traffic Safety Administration (NHTSA) to assess a driver’s level of impairment. The three standardized tests include:
- Horizontal gaze nystagmus test (HGN): The officers observe your eye movements while you follow a moving object.
- Walk-and-turn test: This requires you to walk heel-to-toe in a straight line before turning around to assess your balance and coordination.
- One-leg stand test: This also tests your balance and coordination
These tests may appear simple, but there are many factors that can affect their outcome, such as:
- The officer’s interpretation of the results, which could be affected by bias, fatigue or lack of experience
- Physical or medical conditions of the individual, including inner ear problems, injuries or neurological disorders
- Language barriers experienced by non-native English speakers or people who are neurodivergent
- The environment, such as uneven pavement, poor lighting or bad weather
- Officers are allowed to use the results of field sobriety tests in court, and if you don’t test well, it could strengthen their case.
Even though you are within your rights to refuse a field sobriety test, the officer may still arrest you based on other observations. If that occurs, you will want legal guidance in understanding your rights and building a strong defense.