Standardized Field Sobriety Tests

There are three major studies that have evaluated the DUI field sobriety tests. The Colorado Validation Study was conducted in 1995. The Florida Validation Study in 1997, and the San Diego Validation Study in 1998. The validation studies were conducted in conjunction with or sponsored by NHTSA. There are only three tests that became standardized field sobriety tests. They must be conducted in a standardized manner. In fact the manual itself states:

IT IS NECESSARY TO EMPHASIZE THIS VALIDATION APPLIES ONLY WHEN:

* THE TESTS ARE ADMINISTERED IN THE PRESCRIBED, STANDARDIZED MANNER
* THE STANDARDIZED CLUES ARE USED TO ASSESS THE SUSPECT'S PERFORMANCE
* THE STANDARDIZED CRITERIA ARE EMPLOYED TO INTERPRET THAT PERFORMANCE.

IF ANY ONE OF THE STANDARDIZED FIELD SOBRIETY TEST ELEMENTS IS CHANGED, THE VALIDITY IS COMPROMISED.

DWI Detection and Standardized Field Sobriety Testing Section VIII-3. 2000.

The standardized field sobriety tests are the Horizontal Gaze Nystagmus, One Leg Stand and the Walk and Turn. The Colorado Validation Study and the Florida Validation Study were conducted when the DUI legal limit was 0.10. The Colorado Validation Study found police officers made the correct arrest decision 93% of the time when they used the three standardized field sobriety tests. The Florida Validation Study found police officers made the correct arrest decision 95% of the time when they used those field sobriety tests.

The San Diego Validation Study was conducted because in 1998 many of the states were lowering the DUI legal limit from 0.10 to 0.08. This experiment answered the question, "Do the standardized field sobriety tests discriminate at breath alcohol content levels below a 0.10 level?" The San Diego Validation Study discovered police officers made correct arrest decisions 91% of the time when using the three standardized field sobriety tests for a DUI legal limit of 0.08.

Horizontal Gaze Nystagmus (HGN)

The suspect is instructed to stand with their feet together and their arms at their sides. The DUI suspect must follow a stimulus with their eyes only, and they are not to move their head when tracking the stimulus. The stimulus is usually a pen or light held 12 to 15 inches in front of the DUI suspect slightly above their eyes. The police officer must first determine if the DUI suspect is a proper candidate for the test. The police officer will check for equal pupil size and will check for equal tracking of the stimulus with a series of passes from the suspect's left to right. If the DUI suspect cannot track the stimulus it may be an indication of a medical disorder or blindness. If the pupils are not of equal size this may indicate a head injury or that the suspect has ingested a heavy narcotic. An experienced police officer will request backup at this point. If either event is present the test should not be conducted.

Lack of Smooth Pursuit

The test begins with the police officer checking for Lack of Smooth pursuit. The stimulus will be moved in a quick steady pace from the suspect's left to right. This action occurs twice. The police officer is looking for the eye to make "jerking" movements as they follow the stimulus. The DUI suspect will not be able to see this, but the individual conducting the test can see this phenomena. If nystagmus is found it is recorded with a checkmark in the police report for whichever eye it was present.

Distinct Nystagmus at Maximum Deviation

During this portion of the test the officer will move the stimulus to a point where the DUI suspect's eye cannot move in that direction any further. The white of the eye will not be showing. The stimulus is held at this position for four seconds. The officer will look for "jerking." This is done twice for each the left and right eye.

Onset of Nystagmus Prior to 45 Degrees

During this segment of the test the officer will move the stimulus in the same manner it is moved during Lack of Smooth Pursuit. However, the speed of the moving stimulus is significantly reduced. It should take four seconds to move the stimulus from the nose to the left shoulder or right shoulder depending upon which eye the officer is evaluating. If the police officer detects nystagmus while moving the stimulus out to the shoulder, the officer must stop and see if the nystagmus persists. If the nystagmus persists the findings are recorded in the police report. If the nystagmus stops the officer must continue to move the stimulus toward the shoulder.

There are a total of six clues. Each eye is evaluated with the three tests. If the DUI suspect triggers four clues the police officer interprets this as a "failed" test. Most Washington State Courts only allow the HGN evidence to establish consumption of alocol.

Walk and Turn

The next standardized field sobriety test is the Walk and Turn. The DUI suspect is told to place their left foot on a line (real or imaginary) and to place their right foot in front of their left foot touching heel to toe. The DUI suspect must place the arms at their sides. The DUI suspect remains in this "Instructional Position" while the police officer explains the test instructions. The DUI suspect cannot start the test until the police officer states, "Begin."

The instructions are:

* When told to begin you will walk nine heel to toe steps, turn, and take nine heel to toe steps back;
* During the turn keep your front foot on the line, and execute the turn by taking a series of small steps with your other foot;
* While walking, keep your arms at your sides, watch your feet at all times and count out loud each step;
* Do not stop until you have finished the test;

The suspect is asked if they have any questions. If there are none the police officer will tell the suspect to begin the test. The police officer is looking for the inability to remain in the "Instruction Position," starting the test too soon, stopping during the test, failing to touch heel to toe, stepping off the line, using the arms for balance, executing an improper turn and finally taking an incorrect number of steps.

If the DUI suspect misses heel to toe once with a gap of 1.5 inches or greater, the suspect will have failed the heel to toe requirement. The police officer looks for other clues as well.

One Leg Stand

The One Leg Stand is the final standardized field sobriety test which requires the DUI suspect to raise either foot of the ground six inches. The suspect's arms must be at the sides during the test. They must look at their raised foot and point their toe forward. The DUI suspect must count one thousand and one, one thousand and two, one thousand and three, and so forth until the police officer tells the suspect to stop. The police officer will require you perform this test for 30 seconds.

The police officer looks for the DUI suspect to sway during the test, raise their arms six inches away from their body, drop their foot and if the suspect hops during the test.

Totality of the Circumstances

All of these tests assist a police officer in establishing probable cause to make an arrest for the crime of Driving Under the Influence. Police officers are not expected to prove beyond a reasonable doubt guilt of a crime before making an arrest. This would be unreasonable. However, these tests are quite subjective. The author of Washington State DUI is certified to administer the standardized field sobriety tests. Many people fail these tests even when they have not consumed one drop of intoxicants. Anyone can establish a suspicion someone is under the influence by merely looking at them, but courts and juries require "scientific" evidence in this day of forensics shows like CSI and Forensic Files.