Are Field Sobriety Tests Proof That You Are Driving Impaired?

When police pull you over, whether because they suspect you have been drinking or for an unrelated reason, they are constantly using their powers of observation to detect if you are impaired behind the wheel. The friendly banter in which they engage you as you roll down your window is really a method of observing your speech patterns, your demeanor, and any tell-tale odors on your breath.

If they ask you to step outside your vehicle to perform field sobriety tests, you should know that the law does not compel you to submit to these tests as it does with chemical blood alcohol tests. Nevertheless, the following is an explanation of what to expect if you comply with an officer’s request to take roadside sobriety tests.

Three approved tests

The standard tests police in Florida and across the country use to determine if there is enough evidence to arrest you for DUI include these three:

  • The horizontal gaze nystagmus
  • The walk-and-turn
  • The one-leg stand

Each of these relies on the observation and judgment of the arresting officer. Although the National Highway Traffic Safety Administration has approved these tests as scientifically valid for demonstrating the intoxication of a driver, there are numerous factors that may render the results of these tests invalid. If you failed the FSTs and police subsequently arrested you, you have every right to challenge the results in court.

The basics of FSTs

The horizontal gaze nystagmus refers to the way your eyeball jerks involuntarily when you look to the side. The consumption of alcohol causes an exaggeration of the jerking. If you cannot follow the officer’s finger smoothly or if your eye begins to jerk before reaching a 45-degree angle, the officer may determine that you are likely intoxicated. However, over 20 percent of the time, the arresting officer is mistaken.

An officer may ask you to walk forward for nine steps with your heel touching your toes before turning and walking back. During this walk-and-turn test, the officer will be observing numerous factors, including how well you can keep your balance and follow the instructions. Because many medical conditions can make this exercise challenging, about half of those who fail this FST have a BAC below the legal limit.

The one-leg stand, as its name implies, requires you to stand for 30 seconds with one foot off the ground. You may not use your arms to balance or put your foot down without failing the test. As you can imagine, this is difficult for many people to pass who have had no alcohol to drink.

Other tests

If you have a medical condition that would prevent you from successfully performing any of these three tests, you may tell the officer, who will likely substitute it for an alternative FST. If roadside sobriety tests result in your arrest, you would do well to seek legal assistance as early as possible.

If you are facing DUI charges, contact our defense attorneys in St. Augustine today.


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