Legal Definitions - sobriety test

A sobriety test is a procedure or method used to determine if an individual is under the influence of alcohol or drugs to an impairing degree. These tests can involve assessing physical coordination, mental faculties, or using specialized equipment to measure the presence of intoxicating substances in the body.

• Example 1: After a minor car accident, a police officer asks one of the drivers to blow into a handheld device that measures their blood alcohol content (BAC). This device provides an immediate reading of the alcohol level in their breath.

  Explanation: This illustrates a sobriety test using a mechanical device to objectively measure the presence and concentration of alcohol, helping to determine if the driver is intoxicated.

• Example 2: A construction company has a policy requiring employees to undergo drug testing if they are involved in an on-site incident. Following a minor equipment malfunction, an employee is asked to provide a urine sample for analysis.

  Explanation: This demonstrates a sobriety test in a workplace context, where a biological sample is analyzed to detect the presence of drugs, indicating potential impairment.

• Example 3: In an emergency room, a doctor suspects a patient exhibiting slurred speech and disorientation might be intoxicated. The doctor asks the patient to walk a straight line heel-to-toe across the room, observing their balance and coordination.

  Explanation: This shows a sobriety test used in a medical setting, where a coordination exercise helps a healthcare professional assess a patient's level of impairment.

A Field Sobriety Test (FST) is a specific set of physical and mental exercises administered by a law enforcement officer at the scene of a traffic stop. The purpose of an FST is to evaluate a driver's impairment due to alcohol or drugs and to help the officer determine if there is sufficient probable cause to make an arrest for driving under the influence (DUI).

• Example 1: During a late-night traffic stop, an officer asks a driver to stand with their feet together, arms at their sides, and then raise one leg approximately six inches off the ground, holding it for 30 seconds while counting aloud. The officer observes if the driver sways, uses their arms for balance, or puts their foot down.

  Explanation: This is a common FST designed to assess a driver's balance, coordination, and ability to follow instructions and divide their attention, all of which can be impaired by alcohol or drugs.

• Example 2: An officer instructs a driver to follow the tip of a pen with their eyes, moving only their eyes and not their head, as the pen is moved horizontally from side to side. The officer is looking for involuntary jerking of the eyes, known as nystagmus.

  Explanation: This FST, known as the Horizontal Gaze Nystagmus test, is used to detect specific eye movements that are often indicative of central nervous system depressant impairment, such as from alcohol.

• Example 3: After pulling over a driver for erratic lane changes, an officer asks them to recite a specific sequence of numbers backward, such as from 75 down to 60. The officer notes any hesitation, mistakes, or difficulty in completing the task.

  Explanation: This FST assesses a driver's mental processing, memory, and ability to concentrate on a task, which can be significantly affected by intoxication.