Understanding the Standardized Field Sobriety Tests in Drunk Driving Cases
All too often in the world of criminal defense drunk driver representation, attorneys who do not concentrate in drunk driving defense will take on winnable drinking and driving cases and advise their clients to plead guilty. In many cases, the reason for this bad advice is based on an erroneous interpretation of the police report generated by the arresting officer. Contained within the report will undoubtedly be the officer’s rendition of the client’s performance of the officer’s field sobriety tests. Knowing and understanding the science behind the standardized tests, as well as the validity of the tests is vital to a successful defense for your client accused of drinking and driving.
WHAT IS STANDARDIZED FIELD SOBRIETY TEST?
The United States Government, through the National Highway Traffic Safety Administration (NHTSA) has sponsored various studies and academic research to develop a uniform and relatively simple means to determine intoxication through a performance of tests. The purpose of this sponsorship was to provide police officers investigating drunk driving cases the ability to determine, as well as evidence, whether or not a drinking and driving suspect was under the influence of alcohol. The results of these efforts are the “Standardized Field Sobriety Tests,” commonly known as SFST’s.
The SFTS’s consist of three specific physical tests, which taken together are alleged to show a high likelihood that an individual’s blood alcohol content is over the legal limit. Specifically, these tests include the Walk and Turn, One-Leg Stand, and Horizontal Gaze Nystagmus Test.
THE HORIZONTAL GAZE NYSTAGMUS TEST
The Horizontal Gaze Nystagmus (HGN) Test is the test which the officer puts his or her finger in front of the suspect’s eyes and waives them around. Unfortunately for many drunk driving defendants, their lawyers do not understand how the officer is supposed to properly perform the test, nor do they realize what the officer is looking for. Nystagmus is an abnormal jerky movement of the eye. There is some questionable academic literature which finds that people with blood alcohol levels over the legal limit will have the presence of nystagmus in their eyes.
Prior to the performance of the test, the officer is required to check for “equal tracking” of the eyes by moving their finger or another object quickly across the face of the drunk driving suspect. Equal tracking means that the eyes have to move in uniform and at the same speed. Next, the officer is required to check to make sure the drinking and driving suspect’s pupils are of equal size. Finally, the officer is required to ask questions to the suspect regarding having any ailments which may result in a false positive on the HGN test.
The actual HGN test is then performed. The test itself consists of a six point system in which three different tests are performed on each eye, and if the sum of failed tests equals four or more points, the suspect is considered to have failed the test. Here are the tests as follows:
LACK OF SMOOTH PURSUIT – The officer moves the object slowly but steadily from the center of the subject’s face towards the left ear. The left eye should smoothly follow the object, but if the eye exhibits nystagmus, the officer notes the clue. The officer then checks the right eye.
DISTINCT NYSTAGMUS AT MAXIMUM DEVIATION – Starting again from the center of the suspect’s face, the officer moves the object toward the left ear, bringing the eye as far over as possible, and holds the object there for four seconds. The officer notes the clue if there is a distinct and sustained nystagmus at this point. The officer holds the object at maximum deviation for at least four seconds to ensure that quick movement of the object did not possibly cause the nystagmus. The officer then checks the right eye. This is also referred to as “end-point” nystagmus.
ANGLE OF ONSET OF NYSTAGMUS PRIOR TO FORTY-FIVE DEGREES – The officer moves the object at a speed that would take about four seconds for the object to reach the edge of the suspect’s left shoulder. The officer notes this clue if the point or angle at which the eye begins to display nystagmus is before the object reaches forty-five degrees from the center of the suspect’s face. The officer then moves the object towards the suspect’s right shoulder. For safety reasons, law enforcement officers usually use no apparatus to estimate the forty-five degree angle. Generally, forty-five degrees from center is at the point where the object is in front of the tip of the subject’s shoulder.
THE ONE-LEG STAND
In the One-Leg Stand test, the impaired driving suspect is instructed to stand with one foot approximately six inches off the ground and count aloud by …