Field Sobriety Tests in Michigan: A Detailed Guide for Drunk Driving Cases

In Michigan, Field Sobriety Tests (FSTs) are frequently used by law enforcement officers during traffic stops to assess whether a driver is impaired by alcohol or drugs. These tests, developed and standardized by the National Highway Traffic Safety Administration (NHTSA), are intended to provide officers with probable cause to make a DUI arrest. However, they are not infallible and are subject to strict guidelines that must be followed for the results to hold weight in court.

This guide will explore the three standardized field sobriety tests, their administration, how they are scored, and how their performance applies to drunk driving cases in Michigan.

The Purpose of Field Sobriety Tests in Michigan

Field sobriety tests aim to evaluate a driver’s:

1. Balance and Coordination: Alcohol and drugs often impair motor skills, which these tests are designed to detect.
2. Cognitive Functioning: The ability to follow instructions and maintain focus is crucial during these tests.
3. Physical Indicators of Impairment: Officers observe physical behaviors like swaying, using arms for balance, or failing to follow specific instructions.

In Michigan, these tests play a critical role in DUI investigations. However, they must be administered correctly to be considered reliable evidence.

The Three Standardized Field Sobriety Tests

The NHTSA has approved three standardized FSTs. Each has specific instructions that officers must follow and observable clues they must document. If these protocols are not followed, the results can be challenged in court.

1. Horizontal Gaze Nystagmus (HGN) Test Overview:

The HGN test evaluates involuntary jerking of the eye, which becomes more pronounced when someone is impaired by alcohol.

How It’s Administered:

• The officer holds a stimulus (such as a pen or flashlight) about 12-15 inches from the driver’s face.
• The driver is instructed to follow the stimulus with their eyes only, without moving their head.
• The officer moves the stimulus smoothly from side to side, observing each eye for signs of nystagmus.

Clues of Impairment:

• Lack of Smooth Pursuit: The eyes cannot follow the stimulus smoothly.
• Distinct Nystagmus at Maximum Deviation: Jerking occurs when the eye is at its farthest point to the side.
• Onset of Nystagmus Before 45 Degrees: Jerking begins before the eye reaches a 45-degree angle.

Scoring:

Each eye is evaluated separately, and each clue counts as one point, for a total of six possible clues. If four or more clues are present, the driver is likely impaired according to NHTSA standards.

Challenges to This Test:

• Improper lighting or distractions can affect results.
• Certain medical conditions, such as inner ear disorders, can cause nystagmus unrelated to alcohol.

2. Walk-and-Turn (WAT) Test Overview:

This test evaluates a driver’s ability to follow instructions and maintain balance while walking in a straight line.

How It’s Administered:

• The officer provides specific instructions and demonstrates the test.
• The driver is instructed to:
  1. Take nine heel-to-toe steps along a straight line.
  2. Turn using a series of small steps as demonstrated by the officer.
  3. Return with nine heel-to-toe steps along the same line.
• The driver must keep their arms at their sides and count each step out loud.

Clues of Impairment:

• Cannot keep balance during instructions.
• Starts walking before being told to do so.
• Misses heel-to-toe on any step.
• Uses arms for balance.
• Steps off the line.
• Takes the wrong number of steps.
• Turns incorrectly or loses balance during the turn.
• Stops walking to regain balance.

Scoring:

Two or more clues indicate impairment according to NHTSA standards.

Challenges to This Test:

• Uneven or slippery surfaces can make it difficult to perform.
• Physical conditions, such as injuries or obesity, can affect performance.
• Nervousness or anxiety may cause errors unrelated to impairment.

3. One-Leg Stand (OLS) Test Overview:

This test assesses balance, coordination, and concentration by requiring the driver to stand on one leg while performing a task.

How It’s Administered:

• The officer demonstrates the test and provides instructions.
• The driver is instructed to:
  1. Stand with one foot approximately six inches off the ground.
  2. Keep both arms at their sides.
  3. Count out loud (e.g., "one thousand one, one thousand two") until told to stop.
• The test lasts approximately 30 seconds.

Clues of Impairment:

• Swaying while balancing.
• Using arms for balance.
• Hopping to maintain balance.
• Putting the raised foot down.

Scoring:

Two or more clues indicate impairment.

Challenges to This Test:

• Age or medical conditions, such as back or leg injuries, can affect performance.
• Environmental factors like wind, uneven ground, or poor footwear can influence results.

How Field Sobriety Tests Must Be Performed in Michigan

In Michigan, officers must adhere to strict guidelines when administering FSTs:

• Proper Instructions: Officers must provide clear and specific instructions for each test.
• Demonstration: Officers must demonstrate each test before the driver performs it.
• Documentation: Observations must be meticulously documented, including any clues of impairment and the driver’s behavior during the test.
• Conditions: Tests should be conducted in a well-lit area, on a flat surface, and away from distractions whenever possible.

Failure to follow these protocols can weaken the reliability of the test results and provide grounds for legal challenges.

How to Interpret Field Sobriety Test Results

While these tests are designed to detect impairment, they are not definitive evidence of drunk driving. Performance on these tests can be influenced by:

• Medical Conditions: Inner ear problems, neurological disorders, or injuries can mimic signs of impairment.
• Environmental Factors: Poor lighting, uneven surfaces, and bad weather can lead to errors.
• Emotional State: Nervousness, anxiety, or fatigue can affect coordination and focus.

In Michigan drunk driving cases, an experienced attorney can scrutinize how these tests were conducted and challenge their validity if proper procedures were not followed.

Defending Against Field Sobriety Test Results in Michigan DUI Cases

An attorney experienced in Michigan DUI law can:

• Question whether the officer followed NHTSA guidelines.
• Highlight medical or environmental factors that could explain poor performance.
• Argue that the tests are inherently subjective and prone to error.

Conclusion

Field sobriety tests are a critical tool in Michigan drunk driving cases, but they are far from perfect. Understanding how these tests work, how they should be performed, and their potential shortcomings can be vital for anyone facing DUI charges.
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If you’ve been charged with a DUI in Michigan, it’s crucial to work with an experienced attorney who can evaluate the validity of the field sobriety tests in your case and build a strong defense. For comprehensive guidance, visit www.michiganduiplaybook.com.