Sarah Toney has published a chapter on Field Sobriety Testing for a Defending DUI book. The book is published by the Illinois Institute of Continuing Legal Education (IICLE), a highly regarded provider for legal education.
The chapter on Field Sobriety Testing covers the 3 standardized tests which officers should administer to people suspected of being under the influence of alcohol. These tests are:
- the Horizontal Gaze Nystagmus Test ("HGN") which is commonly referred to as the "eye test". Here the officers look for the involuntary jerking of the eyes. While there are more than 25 different causes of nystagmus, one cause is the consumption of alcohol. Some people naturally have nystagmus in their eyes.
- the Walk and Turn test. This is a test where the officer has the person walk 9 heel-to-toe steps in a straight line with their hands at their side, counting out loud. After the 9th step the person is to turn around in a series of small steps, and take 9 heel-to-toe steps back to where they started.
- the One Legged Stand test. This is a test where the officer instructs the person to chose one foot to lift off the ground. Keeping their hands at their sides, the person is to count in this manner: 1-1000-1, 1-1000-2, 1-1000-3, until told to stop. This test should go on for 30 seconds with no hopping or swaying.
The chapter also discusses the training manuals used to train police officers. These manuals include studies that have been done on the 3 SFSTs (standardized field sobriety tests). It is interesting to note that there have been no studies so far that have tested these field sobriety tests with the consumption of drugs, only alcohol. Over the years, the manuals have changed and the chapter discusses in length the changes that have occurred over the years.