Call us 24/7 (727) 388-4736

DUI Field Sobriety Tests (FSTs)

If you have been arrested for DUI, and took DUI Field Sobriety Tests, in the Tampa Bay Area including St. Petersburg, Clearwater, Pinellas County, Tampa, Hillsborough County, or surrounding counties, contact the Morris Law Firm, P.A. for specific information and experience on DUI Field Sobriety Tests cases in Pinellas and Hillsborough Counties.

What are DUI Field Sobriety Tests (FSTs)?

Field Sobriety Tests (FSTs) are a series of standardized physical and/or cognitive performance tests given to a driver under reasonable suspicion of Driving Under the Influence (DUI) to provide law enforcement with probable cause to arrest the driver for DUI. The results of the FSTs (including the video recording of the tests) may be used as evidence in court.

The standard Field Sobriety Tests (FSTs) include:

  • Horizontal Gaze Nystagmus (HGN)
  • Walk-and-Turn (WAT)
  • One-Leg Stand (OLS)

The National Highway Traffic Safety Administration (NHTSA) developed a standardized system for law enforcement to administer the Field Sobriety Tests. Law enforcement agencies in the Tampa Bay area use the NHTSA recommended Field Sobriety Tests.

While the three standard tests above are most commonly used, local law enforcement agencies have the latitude to introduce other tests as they see fit. In Tampa Bay Florida these may include:

  • Finger-to-Nose Test
  • Romberg Alphabet Test
  • Counting Test


The tests above are typically used when a driver discloses during the course of a DUI investigation that they have physical ailments or limitations that prohibit them from successfully completing the standardized Field Sobriety Tests.


How Are Field Sobriety Tests Invoked:

When driving, there are several ways to come into contact with a law enforcement officer who may then have reasonable suspicion to conduct Field Sobriety Tests to determine if you are Driving Under the Influence. These include:

  • Automobile accidents
  • DUI Roadblocks / Sobriety Checkpoints
  • Law enforcement officer observations (erratic driving, swerving, weaving, drifting, etc.)
  • Reports of erratic driving
  • Another traffic offense


When a driver is contacted by law enforcement, the officer is looking for signs of impairment that will provide reasonable suspicion to conduct an investigation for Driving Under the Influence (DUI). During the initial interaction with the driver the officer looks for bloodshot or glassy appearance of the eyes, any odor of alcohol on the breath, or slurred or slow speech. If the officer observes any of these signs of impairment (or if they have already established reasonable suspicion from one of the events listed above) they can claim reasonable suspicion to conduct Field Sobriety Tests (FSTs) to attempt to prove impairment.


What to Expect During DUI Field Sobriety Tests (FSTs):

The law enforcement officer will typically ask the driver to step out of the vehicle and indicate that they are conducting a DUI investigation. At this time, the law enforcement officer will begin a battery of Field Sobriety Tests.

You have no legal obligation to perform Field Sobriety Tests. However, if you refuse to take Field Sobriety Tests, it is likely you will still be arrested for DUI. Ultimately though, your case will be more difficult for the State Attorney’s Office to prosecute given the lack of Field Sobriety Test evidence.

If the driver submits to the battery of Field Sobriety Tests, they can expect the following:

Horizontal Gaze Nystagmus Test:
The officer will first conduct a Horizontal Gaze Nystagmus (HGN) Test by stating, “I am now going to check your eyes.” In fact, the officer is not checking the subject’s eyes as in an eye exam, but looking for a sign of impairment – specifically nystagmus. Nystagmus is an involuntary jerking or bouncing of the eyeball over which an individual has absolutely no control. Consumption of alcohol or other depressants limits the ability of the brain to correctly control eye muscles, therefore causing the nystagmus. Officers are trained to administer a HGN Test by having the subject follow an object horizontally across their gaze.

The officer is looking for the subject’s eyeball to jerk or bounce as they track the object. The officer is looking for any indicators of impairment:

  • Any lack of smooth pursuit while tracking the object
  • Any distinct nystagmus at maximum deviation
  • Any onset of nystagmus prior to 45 degrees

The officer may also have the subject complete a vertical nystagmus test to check for the influence of high doses of alcohol, depressants or inhalants, and the consumption of the drug phencyclidine (PCP).

Research indicates that a majority of individuals who exhibit signs of nystagmus in the test will have a BAC of 0.10 or greater.

Walk-and-Turn (WAT) Test:
The Walk-and-Turn Test is a divided attention test – the subject must follow verbal instructions while also performing physical movements. Impaired drivers may have difficulty with tests requiring their attention to be divided between simple mental and physical exercises. In the Walk-and-Turn Test, the subject is instructed to take nine steps, heel-to-toe, along a straight line. After taking the steps, the subject must turn on one foot and return in the same manner in the opposite direction. In many cases they may also be asked to count out the steps in the exercise as the complete it.

The officer is looking for eight indicators of impairment:

  • Inability to keep balance while listening to the instructions
  • Beginning before the instructions are finished
  • Stopping while walking to regain balance
  • Not touching heel-to-toe
  • Stepping off the line
  • Using arms to balance
  • Making an improper turn
  • Taking an incorrect number of steps

The officer will note when the subject exhibits two or more indicators of impairment as research indicates that a majority of individuals who exhibit two or more indicators will have a BAC of 0.08 or greater.

One-Leg Stand (OLS) Test:
The One-Leg Stand Test is also a divided attention test. The officer will instruct the subject to stand with one foot approximately six inches off the ground and count aloud by thousands (One thousand-one, one thousand-two, etc.) until told to put the foot down. The officer times the subject for 30 seconds.

The officer is looking for eight indicators of impairment:

  • Swaying while balancing
  • Using arms to balance
  • Hopping to maintain balance
  • Putting the foot down

The officer will note when the subject exhibits two or more indicators of impairment as research indicates that a majority of individuals who exhibit two or more indicators will have a BAC of 0.08 or greater.

Based on the results of the Field Sobriety Tests the officer may have probable cause to arrest the subject. In this case the driver is placed under arrest for DUI and per Florida Statute316.1932 (1)(a)1.a. requested to submit to, “an approved chemical test or physical test,” which is usually a breath test to determine the alcoholic content of his or her blood or breath. The breath test may be conducted by the officer if a mobile breath test device is available to them (portable or preliminary breath tester or PBT), or in a mobile breath alcohol testing vehicle (“BAT Mobile”), or at the police station (conducted using the Intoxilyzer 8000), typically after a 20 minute observation period. Any result of .08 or above is considered to be legally impaired under Florida law.


Back to top

Florida Law and DUI Field Sobriety Tests (FSTs):

Florida law allows a law enforcement officer to request that a driver take Field Sobriety Tests when the officer has reasonable suspicion that the driver is under the influence. There is no law or Florida State Statute that requires a Florida driver to submit to Field Sobriety Tests.


Back to top

Issues / Potential Defenses:

There are many ways to contest the results of Field Sobriety Tests. As noted above, one way to make it more difficult for the State Attorney’s Office to prosecute your case is to refuse the Field Sobriety Tests altogether. This way, the State will have less evidence to prove that the driver was in fact under the influence.

Field Sobriety Tests are heavily subjective, and rely on the observations, opinions, prejudices, and training of the arresting officer. Results of a Field Sobriety Test may be challenged in this regard based on:

  • Inadequate officer training
  • Failure to properly administer the tests
  • Inappropriate grading of the tests
  • False positive results


Additionally, drivers have a host of physical, mental and environmental factors that may influence the results of a Field Sobriety Test. Results of a Field Sobriety Test may be challenged in this regard based on:

  • Medical condition or injury affecting the ability to successfully complete the tests
  • Age – those 65 or older may have issues successfully completing the tests
  • Gender – women may have special issues successfully completing the tests
  • Weight – those over 50 pounds overweight may have issues successfully completing the tests
  • Hearing – those with hearing conditions may not be able to clearly hear the instructions
  • Environment – lighting, noise, ground conditions and weather may all factor into the results of the tests


It should be noted that many sober people are unable to perform the Field Sobriety Tests successfully with reported false positive rates of 23%. It has also been reported that the Walk-and-Turn (WAT) Test is only 68% accurate, while the One-Leg Stand (OLS) Test is only 65% accurate in healthy subjects.


We will strive to file any necessary motions to dismiss or motions to attempt to exclude evidence in an effort to maximize your opportunity for a positive outcome. As your criminal defense lawyer, we will represent you at any necessary pre?trial hearings, pre?trial motions, and at trial.


Back to top

What To Do Next:

If you have been arrested for DUI:

1. Don’t speak to the police – ask to have an attorney present.
2. Don’t give a written statement – again, ask to have an attorney present.
3. Contact an attorney immediately.
4. Collect and document your own evidence.


Time is of the essence.
Time is of the essence.

You have a very narrow window of time between when you are arrested and when the State Attorney’s office makes a decision to file a criminal charge against you. Hiring an attorney immediately to negotiate on your behalf gives you the best chance of avoiding criminal charges.

Hire the Morris Law Firm and let us fight for you


Morris Law Firm, P.A. | St. Petersburg DUI Field Sobriety Tests Attorney

If you have been arrested for DUI and took DUI Field Sobriety Tests, contact a DUI defense lawyer in St. Pete to discuss possible defenses and specific strategies that may exist in your case. Call the Morris Law Firm, P.A. at (727) 388-4736 to discuss your case directly with an attorney, or fill out our online form to be contacted for a Free Initial Consultation. The Morris Law Firm, P.A. can help and has specific knowledge and experience in defending DUI offenders throughout St. Petersburg, Clearwater, Largo, and nearby areas.