The subjective nature of field sobriety tests

The subjective nature of field sobriety tests

If police arrest you for drunk driving, they may have made up their minds that you were intoxicated long before they approached your vehicle. Perhaps your car swerved over the yellow line, or you were driving too slowly, as people tend to do when police are following them.

A New Jersey officer who already suspects you of driving under the influence will use every moment of his or her encounter with you to collect evidence to support that suspicion. Once the officer has enough probable cause, he or she can place you under arrest. One common tool law enforcement uses to gain probable cause is the standard field sobriety test. Understanding the implications and weaknesses of these tests may help you make important decisions if you face a DUI arrest.

A judgement call

The National Highway Traffic Safety Administration has officially approved three SFSTs based on scientific evidence that the combination of these three challenges confirms that a driver is legally intoxicated 90 percent of the time when a trained police officer properly administers them. The three tests are these:

  • Horizontal gaze nystagmus: An officer holds an object in front of you and asks you to follow it with your eyes so he or she can measure the involuntary jerking of your eyeball when you look side to side, which drinking alcohol tends to exaggerate. However, an officer who is poorly trained may not be able to recognize your normal nystagmus. Additionally, the officer may not know of any medical conditions you may have that exaggerate your eye jerking.
  • Heel-to-toe walk: Police will instruct you to walk forward with the heel of one foot touching the toes of the other. You will turn and walk back to the starting point. Officers will judge whether you follow the directions exactly, lose your balance or sway, or are unable to touch your heel to your toes. They may not take into consideration the unevenness of the terrain, the noise from traffic or even the shoes you are wearing as factors that may hinder you from passing the test.
  • Standing on one leg: With one foot six inches off the ground, you will stand for about 30 seconds while counting from 1,001. You may not sway, balance yourself with your arms, hop or drop your foot. Of course, if you have an illness or other factor that affects your balance, such as allergies, an ear infection, arthritis or certain medications, police may not distinguish between those issues and the chance that you are intoxicated.

While studies show that field sobriety tests are reliable indicators of a driver’s level of impairment, they may not be so reliable if a poorly trained, inexperienced officer administers them. This is why you would do well to contact an attorney at the earliest moment following a DUI arrest.