What Tests Are Part of the Broader Standardized Field Sobriety Test?

Standardized Field Sobriety Tests (SFSTs) are a series of physical and cognitive assessments used by law enforcement officers to determine if a driver is impaired by alcohol or drugs. These tests were developed and validated by the National Highway Traffic Safety Administration (NHTSA) in the 1970s and have since become a crucial tool in identifying and prosecuting impaired drivers across the United States.

The Three Primary Standardized Field Sobriety Tests

The broader SFST consists of three primary tests, each designed to evaluate different aspects of a person’s physical and mental coordination:

1. Horizontal Gaze Nystagmus (HGN) Test

The HGN test is based on the observation that alcohol and certain drugs can cause involuntary jerking of the eyes, known as nystagmus. During this test:

• The officer holds a small object (often a pen or flashlight) about 12-15 inches from the subject’s face.
• The subject is instructed to follow the object with their eyes without moving their head.
• The officer moves the object smoothly from side to side, looking for three indicators of impairment: a) Lack of smooth pursuit b) Distinct nystagmus at maximum deviation c) Onset of nystagmus prior to 45 degrees

2. Walk-and-Turn (WAT) Test

This test assesses a person’s ability to follow instructions and perform physical movements. The subject is required to:

• Take nine heel-to-toe steps along a straight line
• Turn on one foot
• Return in the same manner in the opposite direction

The officer looks for eight potential indicators of impairment, including:

• Inability to maintain balance while listening to instructions
• Beginning before instructions are finished
• Stopping while walking
• Failure to touch heel-to-toe
• Stepping off the line
• Using arms for balance
• Improper turn
• Incorrect number of steps

3. One-Leg Stand (OLS) Test

This test evaluates a person’s balance and coordination. The subject is instructed to:

• Stand with one foot approximately six inches off the ground
• Count aloud by thousands (One thousand-one, one thousand-two, etc.) until told to put the foot down

The officer looks for four main indicators of impairment:

• Swaying while balancing
• Using arms to balance
• Hopping
• Putting the foot down

Additional Tests and Observations

While the HGN, WAT, and OLS tests form the core of the Standardized Field Sobriety Test battery, officers may employ additional tests or make further observations to assess impairment:

4. Preliminary Breath Test (PBT)

Although not part of the standardized tests, many jurisdictions allow officers to use portable breath testing devices to estimate a person’s blood alcohol concentration (BAC) in the field.

5. Romberg Balance Test

This test requires the subject to stand with their feet together, head tilted back, eyes closed, and estimate the passage of 30 seconds.

6. Finger-to-Nose Test

The subject is asked to touch the tip of their nose with the tip of their index finger while their eyes are closed.

7. Alphabet Test

The subject may be asked to recite a portion of the alphabet or count backwards from a specific number.

8. General Observations

Throughout the interaction, officers observe and document the subject’s overall appearance, behavior, and other signs of potential impairment, such as:

• Slurred speech
• Bloodshot or watery eyes
• Odor of alcohol
• Fumbling with license and registration
• Difficulty exiting the vehicle

Significance and Limitations of SFSTs

The Standardized Field Sobriety Tests have been scientifically validated and are widely accepted in courts as evidence of impairment. However, it’s important to note their limitations:

• False Positives: Certain medical conditions, injuries, or environmental factors can cause a person to perform poorly on these tests even when sober.
• Subjectivity: While standardized, there is still an element of subjective interpretation by the officer administering the tests.
• Limited Scope: SFSTs were primarily developed to detect alcohol impairment and may be less effective in identifying impairment from other substances.

Despite these limitations, SFSTs remain a valuable tool for law enforcement in combating impaired driving. They provide officers with a standardized method to establish probable cause for arrest and further chemical testing.

Conclusion

The Standardized Field Sobriety Tests consist primarily of the Horizontal Gaze Nystagmus, Walk-and-Turn, and One-Leg Stand tests. These assessments, along with additional observations and sometimes supplementary tests, form a comprehensive approach to evaluating driver impairment in the field. While not perfect, these tests play a crucial role in identifying and removing impaired drivers from the roads, contributing to public safety efforts nationwide.

FAQ: Standardized Field Sobriety Tests

Q1: Are field sobriety tests mandatory?

A1: In most jurisdictions, field sobriety tests are voluntary. However, refusing to take them may still result in arrest if the officer has other reasons to suspect impairment.

Q2: Can medical conditions affect performance on field sobriety tests?

A2: Yes, various medical conditions, such as inner ear problems, leg or back injuries, and neurological disorders, can affect performance on these tests.

Q3: Do I have the right to consult an attorney before taking field sobriety tests?

A3: Generally, you do not have the right to consult an attorney before deciding whether to take field sobriety tests during a traffic stop.

Q4: Can field sobriety test results be challenged in court?

A4: Yes, the results can be challenged. Factors such as improper administration of the tests, environmental conditions, or the subject’s physical limitations can be used to contest the results.

Q5: Are field sobriety tests accurate for detecting drug impairment?

A5: While designed primarily for alcohol impairment, some aspects of SFSTs can indicate drug impairment. However, their accuracy may vary depending on the substance involved.

Q6: Can I pass a field sobriety test if I’m over the legal BAC limit?

A6: It’s possible to perform well on field sobriety tests even while over the legal limit, especially for individuals with high alcohol tolerance. Conversely, some people may perform poorly even when below the limit.

Q7: Are there alternatives to standardized field sobriety tests?

A7: Some jurisdictions use other tests or devices, such as portable breath tests or oral fluid tests. However, the three standardized tests remain the most widely accepted and validated methods.