Field Sobriety Tests
The Standardized Field Sobriety Tests (SFSTs) are a battery of three tests:
The validity of SFST results is dependant upon officers following the established, standardized procedures for test administration and scoring. However, even if the SFSTs are administered according to protocol they are still very inaccurate. According to the government, the accuracy of the SFSTs, in a laboratory setting, are only reliable as follows:
I may be able to suppress the results of an improperly administered test.
- Horizontal Gaze Nystagmus (HGN);
- Walk-and-Turn (WAT); and
- One-Leg Stand (OLS).
The validity of SFST results is dependant upon officers following the established, standardized procedures for test administration and scoring. However, even if the SFSTs are administered according to protocol they are still very inaccurate. According to the government, the accuracy of the SFSTs, in a laboratory setting, are only reliable as follows:
- HGN - 77%
- WAT - 68%
- OLS - 65%
I may be able to suppress the results of an improperly administered test.
HGN - Horizontal Gaze Nystagmus
Commonly called the "eye test." This is usually the first test the cop will ask you to do after ordering out of your car. When a cop asks "can I take a look at your eyes to make sure you are okay to drive?," many people mistakenly think that they are not yet under investigation for DWI. If a cop asks to look at your eyes, then he already suspects you are driving while intoxicated.
Nystagmus means the involuntary jerking of the eyes. HGN refers to an involuntary jerking occurring as the eyes gaze toward the side. In addition to being involuntary, the person experiencing the nystagmus is unaware that the jerking is happening. The theory behind the test is that nystagmus becomes readily noticeable when a person has introduced a central nervous system (CNS) depressant, such as alcohol, into their body.
When administering the test, the officer has the suspect follow the motion of a stimulus, such as a pen or finger, with the eyes only. As the eyes move from side to side each eye is examined for three specific clues:
Nystagmus means the involuntary jerking of the eyes. HGN refers to an involuntary jerking occurring as the eyes gaze toward the side. In addition to being involuntary, the person experiencing the nystagmus is unaware that the jerking is happening. The theory behind the test is that nystagmus becomes readily noticeable when a person has introduced a central nervous system (CNS) depressant, such as alcohol, into their body.
When administering the test, the officer has the suspect follow the motion of a stimulus, such as a pen or finger, with the eyes only. As the eyes move from side to side each eye is examined for three specific clues:
- Lack of Smooth Pursuit - does the eyeball move smoothly or does it noticeably jerk?
- Distinct and Sustained Nystagmus at Maximum Deviation - when the eye is moved as far to the side as possible and stays in that position for several seconds, does it jerk distinctly?
- Onset of Nystagmus prior to 45 degrees - as the eye moves to the side, does it begin jerking prior to going out to a 45 degree angle?
WAT - Walk and Turn Test
The WAT is a divided attention test consisting of two stages: Instruction Stage; and Walking Stage. In the instruction stage, the suspect must stand with their feet in heel-to-toe position, keep their arms at their sides, and listen to instructions. The suspect must maintain the heel-to-toe position and may not begin walking until all instructions are given. In the Walking Stage the suspect takes nine heel-to-toe steps, turns in a prescribed manner, and takes nine heel-to-toe steps back, while counting out loud and watching their feet. Officers observe the suspect's performance for eight clues:
- Can't balance during instructions
- Starts too soon
- Stops while walking
- Doesn't touch heel to toe
- Steps off-line
- Uses arms for balance
- Loses balance on turn, or turns incorrectly; and
- Takes the wrong number of steps.
OLS - One Leg Stand Test
The OLS is also divided into two stages. In the Instruction Stage, the suspect must stand with their feet together, keeping their arms to the side and listen to instructions. In the Balance and Counting Stage, the suspect must raise the leg of his choice approximately 6 inches off the ground, toes pointed out, keeping their legs straight. While looking at the elevated foot, they are instructed to count out load in the following manner: "one thousand and one", "one thousand and two", etc, until told to stop. The officer will instruct the suspect to stop after 30 seconds. The suspect is observed for the following clues:
- Sways while balancing
- Uses the arms for balance
- Hops
- Puts foot down