Welcome back to the fourth installment of my 10-part series on Standard Field Sobriety Tests. I am defense attorney, Leon Matchin, and I want to share some factual information with you about what SFST’s are. If you missed the previous blogs in the series, you can find the last installment on Part III: Optical Intoxication Signs here. This time we’ll take a look at the proper administration of the eye exam.
To briefly recap, last time we talked about how police use certain eye clues for signs of intoxication. The first is what’s known as “smooth pursuit” where the officer looks at how well a suspect is able to follow a moving stimulus. People with a nystagmus will display certain indications, like jerky eye movements while being subjected to this testing. To take that further, if the first shows indication of the condition, a “sustained nystagmus” is checked for—meaning that the movement must be observed continuously for at least four seconds.
If a suspect has any of the first two clues, it is no guarantee that the third clue will be there. Because the 45-degree angle is a key factor in assessing a suspect’s degree of alcohol influence, it is important to know how to estimate that angle. In the manual and demonstration of this by the State Police instructor, an eight inch square template is shown to the students to assist them in estimating this angle, but is rarely—if at all, used by the student or the instructor other than merely pointing out its existence.
Even though this is the case, if used, this devise must be held up so that the suspect’s nose is above the diagonal line. One edge of the template is centered on the nose and perpendicular to or at right angles to the face. The person is told to follow the stimulus until they are looking down the 45-degree diagonal. This obviously is used as practice to recognize the angle.
A rule of thumb that is being taught in order to estimate the 45-degree angle; the stimulus must be halfway between the suspect’s ear and nose on the side being tested or just outside the shoulder area. The estimation of this angle is critical, since studies have shown that as the alcohol increases the angle will decrease. Although this may be the case, this angle should not be used to estimate a specific amount of alcohol in the bloodstream.
In order to properly score this part of the test, the officer must move the object to the 45-degree angle of gaze, taking about four seconds. As the eye follows the object, the jerking is looked for. If nystagmus is observed, the stimulus is stopped and the officer must make an observation that it is continuing at this point. If it continues, then the officer must make sure that there is still white showing in the corner of the eye and the angle must be estimated to be prior than 45-degrees. If it does not, the object must continue to be moved until the jerking does occur and continues or until the 45-degree angle is reached.
If no white of the eye is showing, the eye has either been taken too far to the right, which would be maximum deviation that is being evaluated or the person has unusual eyes that will not deviate very far to the side. The criterion of onset before 45-degrees only can be used if some white can be seen at the outside of the eye. Too often, the officer incorrectly estimates the angle or scores this with no white showing in the corner of the eye or both.
It is important to note that the officer must move the stimulus slowly when performing this part of the HGN test so that it moves from the center to the point just before 45 degrees in no less than four seconds. This test is deemed the most reliable in determining probable cause to believe someone is under the influence of an alcoholic beverage.
This depends on the proper administration, proper scoring, and proper training being adhered to. Even if that is the case, it is still only 77% reliable. A score of four points out of possible six, after both scores of each eye are totaled, the officer is instructed to arrest the suspect for a violation of the New Jersey drunk driving law. This test is not 100% accurate, as three or four subjects during the State Police controlled drinking exercises have scored zero points on this test, yet had a BAC above a .10 and showed little or no other signs of intoxication.
This test should not be administered if the suspect is in a supine position (lying down with face up). It can be administered to them if they are sitting or standing, as long as they are erect. At an accident scene, if a suspect is lying down and this test is performed, it would be invalid due to positional alcohol nystagmus being the cause of the nystagmus encountered. This is called a vestibule type of nystagmus that is evident when the amount of alcohol in the vestibule system is in unequal proportions to the amount of alcohol in the bloodstream and reacts to gravity such as the changing position of the head.
Finally, while officers and troopers may use the HGN to determine probable cause to arrest a defendant, case law in New Jersey prevents this test from being used in actually proving that a driver is intoxicated. In closing, if you have been charged with a DWI based on optical signs of intoxication and the above proper procedure wasn’t followed, give me, attorney Leon Matchin, a call at (732) 662-7658.
Check back soon for Part V on the Walk and Turn test of our Standard Field Sobriety Tests series.