Field Sobriety Test: One-Legged Stand and PBT


Lansing Michigan OWI Attorney

FST– One-legged Stand (OLS) and the Preliminary Breath Test (PBT)

This is the third and final standardized field sobriety test we will be discussing. It is known as the one-legged stand and the driver will be doing just that– standing on one leg for a period of time while maintaining balance. Many people would not be able to successfully perform this test stone sober.


The driver is told to hold one leg six inches off the ground while keeping both legs straight and arms at the sides. Then, they are told to hold the leg off the ground until told to stop. This should terminate after 30 seconds. Sometimes the officer counts silently or tells the driver to count out loud to 30.

There are four clues to judge how well the driver did:

  1. Swaying while balancing
  2. Using arms while balancing
  3. Hopping
  4. Putting the foot down

Any one of these will result in the driver failing this test. Just like with the walk-and-turn, there needs to be a reasonably dry, hard, and non-slippery surface. If the driver is wearing two-inch heels, has back, leg, or middle ear problems, or is 50 pounds overweight, the officer needs to take that into consideration when evaluating or possibly foregoing this particular test all together.

The officer is required to take detailed notes in standard note-taking guides as the descriptions in detail are important in establishing probable cause for the arrest. Unfortunately, they rarely do.


Preliminary Breath Test (PBT)

This is given or offered at the roadside where the officer is conducting the field sobriety tests. It is a portable device that uses an infrared beam that measures the change in energy created by the beam as it passes through the compound that is blown into the chamber. It gives a preliminary reading as to the driver’s blood alcohol content. In order to give an accurate reading, it must be regularly calibrated and have routine maintenance performed and used by someone who is properly trained to use it. Prior to the PBT being administered, the officer administering it must observe the subject for at least 15 minutes to make sure that nothing was placed into the mouth and that there was no regurgitation, belching, or vomiting. Any of these can throw off the reading of the machine. While the results can be used as probable cause for an arrest, it is rarely allowed at trial as evidence. Make sure you have the maintenance records, calibration logs, and certification of the administer to check for any problems. These can obtained through FOIA requests from the police department or sometime through discovery.


If you have been charged with OWI, contact Austin Legal Services, PLC today at (517) 614-1983 to speak to our Michigan OWI attorney to review your case, especially the administering of the field sobriety test.


Representing DUI clients on drunk driving charges throughout Michigan in the counties of Ingham, Eaton, Barry, Clinton, Jackson, Shiawassee, Gratiot, Livingston, Washtenaw, Kent, Calhoun in the cities of Lansing, East Lansing, Mason, Haslett, Okemos, Eaton Rapids, Hastings, St. Johns, Bath, Ithaca, Alma, Jackson, Corunna, Durand, Brighton, Howell, Ann Arbor, Grand Rapids, Kalamazoo, Battle Creek.