Field Sobriety Tests
Unlike blood alcohol content or breath tests, field sobriety tests are voluntary in most states, meaning that in most states, you can decline to take one. For most people, the concern about field sobriety tests happens later, when you've been charged with a DUI.
After a DUI charge, the key is to determine whether or not the field sobriety tests as administered are valid evidence. These tests are usually used when a person is stopped on the suspicion of drinking and driving or at DUI checkpoints.
If you were pulled over and administered a field sobriety test and want more information on your rights and how you may fight these charges, speak with a local DUI lawyer. For a free case evaluation with a local attorney, complete the free form on this page.
The National Highway Transportation Safety Administration created a standardized model for field sobriety testing in 1981. The Standardized Field Sobriety Test (SFST) uses three tests in combination, and the NHTSA recommends that all law enforcement agencies use this standardized program and the associated training.
This standardized testing system - a system that NHTSA has deemed the most reliable of the available field tests - can be a DUI defense in an area where the standardized tests aren't used.
Even where the standardized test is used, there may be some errors in the test. The SFST was designed to help officers measure the appropriateness of making a DUI arrest, not as evidence to prove that a driver was intoxicated.
According to 1998 data from the NHTSA, the combination of three tests used together was only accurate in 91% of DUI cases. The arresting officer is wrong in 9 out of every 100 field sobriety tests - and those were the rates for the officers who volunteered DUI arrest records.
Not all officers who use the SFST as a preliminary DUI assessment have been properly trained to administer and interpret the test. Accurate administration of the three tests according to NHTSA procedures requires that an officer follow strict guidelines. All three tests must be administered under certain conditions.
If you are facing DUI charges, speak with a local DUI attorney to see if the field sobriety tests you took can be challenged. Get advice from a DUI attorney about how to handle the DUI charges you may be facing by calling 877-349-1311 or filling out a free DUI case evaluation form.
Learn more about field sobriety tests:
The One-Leg-Stand Test
The NHTSA procedures for administering the One-Leg-Stand Test require that the officer:
- Instruct the suspect to stand with feet together and arms at the sides, and demonstrate
- Ask the suspect whether he or she understands the instructions
- Explain and demonstrate the test -
- Raise one leg approximately six inches off the ground with the toe pointed out
- Hold the position while counting out loud for 30 seconds saying, "One thousand and one, one thousand and two..."
- Remind suspect to keep arms down and keep watching the raised foot
- Ask the suspect if he or she understands and wait for a response
- Tell suspect to begin the test
- Observe the test from three feet away, while not moving
If the suspect puts a foot down, the police officer will tell him or her to pick it up again and count from where he or she left off. The police officer will end the test after 30 seconds if the suspect counts too slowly, and if the suspect counts very quickly, the police officer will ask him or her to continue until to hold to stop.
» Back to Top
The Horizontal Gaze Nystagmus (HGN) Test
The Horizontal Gaze Nystagmus test provides the most possible ground for challenge among the field sobriety tests. That's because some DUI courts have ruled that it's a scientific test, which requires the state to show that the officer is qualified to interpret the test and testify to the results. While the police officer is performing the field sobriety test, the suspect must keep his or her head still and follow the object with only his or her eyes, focusing on the object until told to stop. Testing procedures require that the officer:
- Hold the stimulus 12-15 inches from the suspect's nose and slightly above eye level
- Move the stimulus smoothly across the suspect's entire field of vision
- Check to see if the eyes are tracking together and if both pupils are the same size
- Start with the left eye, moving the stimulus to the right so it takes 2 seconds to bring the suspect's eye as far to the side as it can and repeat from right to left
- Check at least twice for each of the three clues in each eye:
- Lack of smooth pursuit
- Distinct nystagmus (no white is showing on the side) when the eye is to the outside of field of vision for 4 seconds
- Onset of nystagmus before the eye has moved 45 degrees
» Back to Top
The Walk and Turn (WAT) Test
In addition to the requirements for officer administration, the Walk and Turn Test requires certain conditions to be administered properly. Level ground is required, along with a hard, dry, nonslippery surface. Even with optimal conditions, NHTSA indicates that the test may not be valid for the elderly, people with leg injuries or people with inner ear problems. Officers may still administer the test, but it can provide a DUI defense against the results of the test.
The officer administering the test must:
- Instruct and demonstrate to the suspect to place his or her left foot on the line and right foot heel-to-toe in front of it
- Make sure the suspect understands this position must be held while the instructions are relayed
- Stop the instructions until the suspect is back in position if he or she breaks from the pose
- Tell the suspect not to begin until instructed
- Demonstrate two or three heel-to-toe steps
- Ask the suspect to take nine heel-to-toe
steps down the line, turn around and take nine steps back
- Have the suspect count his or her first step from the heel-to-toe position as the first step
- If the suspect staggers, steps off the line, stops or stumbles, have him or her continue from the point of interruption
While performing the Walk and Turn Test, the suspect must keep both arms down, watch his or her feet, count the steps out loud and not to stop walking until the test is complete. If the suspect indicates that he or she doesn't understand the instructions, the officer can repeat misunderstood parts but not the entire instructions.
When field sobriety tests may not have significant impact on a DUI case if the tests are used only as a tool to help an officer decide whether further action is required. Field sobriety tests can become a critical piece of evidence in a DUI case when a BAC or breath test was refused or the test has been found to be unreliable and suppressed. In those cases, the guidelines set for test administration may provide the support your DUI attorney needs to weaken or even exclude the field sobriety test results.
Some DUI courts may admit field sobriety tests that were administered imperfectly and let the DUI attorney argue the inaccuracy. Other DUI courts have ruled tests not administered according to the NHTSA training are inherently unreliable and excluded as evidence.
» Back to Top
The above summary of field sobriety tests is by no means all-inclusive and is not legal advice. Laws may have changed since our last update. For the latest information on DUI laws, speak to a local DUI lawyer in your state.
