Types of Field Sobriety Tests


Types of Field Sobriety Tests

Here are all of the commonly administered field sobriety tests in detail.

  • The Horizontal Gaze Nystagmus {HGN) Test: This is one of the most widely used tests and you must have seen it being practiced in movies and dramas. This is the one where you are asked to follow a moving flashlight or pen by the

Nystagmus refers to the spontaneous movement of your eyes that normally takes place at the farthest points of your eyes' periphery. However, when a person is high, this movement occurs at less sharp angles.

To find out whether or not you are drunk, the officer dealing with you will move an object in front of your eyes and will ask you to follow it as it is moved back and forth. The officer will look for any twitching in your eyes and the manner in which your eyes chase the moving object. If Nystagmus takes place within 40-45 degrees of your eyes' center, the officer could charge you with DUI violation. If you aren't intoxicated, you won't have any Nystagmus and will be able to easily track the pen or any other object. Moreover, you will be able to observe a motionless object steadily when it is placed at an angle of 45 degrees from your eyes.

In case you fail the horizontal gaze Nystagmus test, it means there is around 0.08 or a higher quantity of alcohol in your system. According to the NHTSA, this test has an accuracy rate of eighty eight percent. However, there are numerous other reasons of Nystagmus that are completely unrelated to intoxication, so this test isn't hundred percent reliable.

  • The Walk and Turn {WAT) Test: This is another test you must have seen in real life, or in movies. You are told to walk straight in a line and take nine steps while keeping your gaze down and have to count out loud. When you take all the 9 heel-to-toe steps, you are asked to turn around. You then have to take another 9 heel-to-toe steps to reach your starting While taking the steps, you must keep both your arms at the sides of your body and you must look down. Moreover, you must not stop unless you are told to.

This test is also referred to as the ‘divided attention' test. Striatum is an important part of your brain and is associated with multitasking. This part and its functions become affected when you drink too much. As a result, you aren't able to multitask and cannot perform physical and mental tests simultaneously. According to the NHTSA, an officer administering this test is in search for eight important indications of intoxication. You will be charged with a DUI offense if you show any of the following signs:

  • If you are unable to maintain your balance while you listen to the officer's instructions
  • If you stop during your walk to recover your balance
  • If you start walking before the officer finishes instructing you
  • If you are unable to touch your heel to the point of your toes
  • If you waver off the straight line
  • If you try to balance by extending your arms
  • If you take a wrong turn
  • If you walk for more or less number of steps than asked by the office.

Besides examining your balance, the officer will also test you on your concentration. Alcohol can impair your hippocampus, which is a part in the brain that forms new memories. If you are heavily intoxicated, then you will not be able to remember a word spoken by the officer, and will be unable to follow numerous instructions at the same time. This test has an accuracy rate of seventy nine percent according to the NHTSA.

  • The One Leg Stand (OLS) Test: This test is a ‘divided attention' test similar to the walk and turn test. It also evaluates your balances. You are asked to stand on one foot by raising it to approximately six inches from the ground. While standing on one foot, you need to count out aloud until the officer asks you to lower down your foot. You are timed for about thirty seconds by the He mainly observes you for four signs:
  • Whether or not you use your arms for balancing yourself
  • Whether not you sway while maintaining your balance
  • Whether or not you hop to regain balance
  • Whether or not you place your foot down

If you do any of these things, the officer's suspicion regarding your intoxication will be confirmed. This test is eighty three per cent accurate. According to the NHTSA, all these three standardized field sobriety tests have an accuracy rate of ninety one percent.

The following tests are labeled as unstandardized field sobriety tests as they aren't accepted by

the NHTSA because of their unreliability. However, they are often practiced in different states.

  • The Romberg Balance Test: If the officer asks you to take this test, you are required to stand erect, shut your eyes and tip your head The officer will inspect you for thirty seconds and till that time, you need to stand straight. The officer will watch you for any vibrations on your eyelids, tension in your muscles, problem while standing steadily and whether or not you need some support for regaining your balance. You need to open your eyes when thirty seconds are over. If you are unable to open your eyes after thirty seconds, or show any of these signs, then you will be most likely charged with DWI violation.
  • Finger to Nose Test: In this test, you are required to stand straight and bring your feet close together. While closing your eyes, you are asked to touch your nose with your index finger. This test is done to examine your balance. As alcohol is best known for affecting your equilibrium, it is likely that you will start shaking, swaying or will have tremors in the eyelids during this test. Moreover, you could even miss your  nose and have tension in the muscles as well. If the officer spots any of these signs, he will arrest you and charge you with DUI crime.
  • Finger Tap Test: This test is also referred to as ‘Finger Counting Test'. In this test, you are asked to extend your hand with your palm facing upward. Now, you need to touch the tips of your finger with your thumb's tip. You also have to count loudly after every tap. Make sure to count both backwards and forwards in three sets. You are charged with DUI violation if you begin the test quickly; are unable to count properly; are unable to touch your fingers' tips to that of your thumb's; stop the exam before you are directed; carry out the incorrect number of counting sets or if you are face difficulty in following  the



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