If you happen to find yourself being subjected to a roadside field sobriety test based on suspicion of being under the influence of alcohol or drugs, there are some things about these tests you need to understand. First, the tests generally fall into two categories. There are:
Standard field sobriety tests (SFST): These tests have actually been subjected to some degree of scientific testing and have been found to be somewhat valid.
Non-standard field sobriety tests (NSFST): These are usually referred to as Field Sobriety Techniques as most have not been subjected to any scientific testing. Nonetheless, their results are generally admissible in Georgia Courts. As such, you should know of/about them FutureOn.
Standard field sobriety tests
SFSTs consist of three evaluations developed by the National Highway Traffic Safety Administration (NHTSA). The three tests are:
Horizontal gaze nystagmus (HGN)
Walk and turn
Horizontal gaze nystagmus is an involuntary jerking of the eyes. This involuntary jerking occurs naturally as the eyes move to the side. This test is usually conducted by moving an object (pen or finger) side to side in front of a person’s face, and asking them to follow it with their eyes. The head must remain stationary. The officer looks for three indicators during the evaluation:
Lack of smooth pursuit (jerking of the eye while following the object)
Distinct and sustained nystagmus at maximum deviation (when the object is way out to the sides of the person’s face, the eyes continue “bouncing” from the corner of the eye opening)
The angle at which jerking starts is within 45-degrees of center
The officer will score the suspect on a 0-6 scale for the number of clues he/she observes. The officer should always observe an even number of clues. In other words, nystagmus is symmetrical. Should 1 eye show a “clue’ on lack of smooth pursuit, the other eye should as well.
The officer is trained to believe that observing 4 or more clues is an indication that the suspect’s blood alcohol level is .10 or higher.
Walk and turn
The walk-and-turn test is conducted by having a person take nine heel-to-toe steps, along a straight line, followed by a turn on one foot and nine steps back in the same direction toward the suspect’s original starting point. The examiner looks for eight “clues” of impairment. The officer will make note of whether or not the suspect:
Cannot keep balance while listening to instructions
Begins before instructions are finished
Stops while walking to regain balance
Does not touch heel-to-toe
Steps off the line
Uses arms to keep balance (raised more than 6″ from the sides)
Makes an improper turn
Takes an incorrect number of steps
The officer will score a suspect on a 0-8 scale based on the number of clues he/she observes. The officer is trained to believe that 2 or more clues suggests that the suspect’s blood alcohol is .10 or higher.
The biggest problem most suspects face, with this test, is that the test involves lengthy instructions. Even a stone sober suspect SHOULD request that the officer repeat, both, the instructions and his/her demonstration of the exam. Most suspects are too nervous to make such a request.
The One-leg stand
The one-leg stand test is conducted by having the suspect stand with one foot approximately six inches off the ground and count aloud to a specific number, or until told to stop. The examiner looks for four indicators of impairment:
Swaying while balancing
Using arms to balance (raised more than 6″ from the sides)
Hopping to maintain balance
Putting the foot down.
The officer should allow the suspect to hold the foot off the ground for 30 seconds.
The officer will score a suspect on a 0-4 scale based on the number of clues he/she observes. The officer is trained to believe that 2 or more clues suggests that a suspect’s blood alcohol is.10 or higher. They are told this is true 65% of the time.