What is Field Sobriety Tests?

Field Sobriety Tests (FSTs) are a series of physical and cognitive exercises that law enforcement officers use to assess a person’s level of impairment due to alcohol or drugs during a traffic stop. These tests are conducted at the scene, typically on the roadside, to help officers determine whether there is probable cause to believe a driver is driving under the influence (DUI) or driving while intoxicated (DWI).

The three Standardized Field Sobriety Tests (SFSTs) established by the National Highway Traffic Safety Administration (NHTSA) are widely used by law enforcement across the United States. These tests include:

✅ Horizontal Gaze Nystagmus (HGN) Test
✅ Walk and Turn Test
✅ One-Leg Stand Test
✅ Other Tests

What is Horizontal Gaze Nystagmus (HGN)?

Horizontal Gaze Nystagmus (HGN) refers to an involuntary, rapid, and jerking movement of the eyes as they move horizontally. This phenomenon is often used as one of the three components in Standardized Field Sobriety Tests (SFSTs) administered by law enforcement officers to assess a person’s level of impairment due to alcohol or drugs during a traffic stop.

During the Horizontal Gaze Nystagmus test, an officer typically uses a stimulus, such as a pen or flashlight, and moves it horizontally in front of the person’s face. The individual is instructed to follow the stimulus with their eyes, while the officer observes for any distinct jerking movement of the eyes.

The presence of nystagmus is considered a potential indicator of impairment, especially when the eyes start jerking before reaching a 45-degree angle from the center. Nystagmus can be more pronounced when a person is under the influence of alcohol or certain drugs, affecting the normal functioning of the eye muscles.

While HGN is a widely used indicator in field sobriety testing, it is not conclusive evidence of intoxication on its own. Various factors, such as medical conditions, can also cause nystagmus. Therefore, HGN is typically just one piece of information that law enforcement considers when determining whether there is probable cause to believe a driver is under the influence.

Drivers have the right to refuse the Horizontal Gaze Nystagmus test, but refusal may have legal consequences, such as license suspension.

Here are the key points regarding Horizontal Gaze Nystagmus (HGN):

1. Involuntary Eye Movement:
   • HGN is characterized by involuntary, rapid, and jerking eye movements as they follow a moving object horizontally.
2. Standardized Testing:
   • HGN is one of the three standardized components of the Standardized Field Sobriety Tests (SFSTs) established by the National Highway Traffic Safety Administration (NHTSA).
3. Alcohol and Drug Impairment:
   • The presence of nystagmus can indicate impairment due to alcohol or certain drugs, affecting the normal functioning of the eye muscles.
4. 45-Degree Angle Indicator:
   • The test involves observing for nystagmus before the eyes reach a 45-degree angle from the center, which is considered a significant indicator of impairment.
5. Use of Stimulus:
   • During the test, a law enforcement officer typically uses a stimulus, such as a pen or flashlight, moving it horizontally in front of the person’s face.
6. Follow the Stimulus:
   • The individual is instructed to follow the stimulus with their eyes while the officer looks for signs of nystagmus.
7. Not Conclusive Evidence:
   • HGN is not a conclusive indicator of intoxication on its own, and its interpretation may be influenced by various factors, including medical conditions.
8. Part of Overall Assessment:
   • HGN is just one element of the overall assessment conducted by law enforcement during a traffic stop to determine whether there is probable cause for further testing or arrest.
9. Right to Refuse:
   • Individuals have the right to refuse the Horizontal Gaze Nystagmus test, but refusal may have legal consequences, such as license suspension.
10. Consideration of Factors:
    • Officers consider various factors, and the results of HGN are evaluated in conjunction with other field sobriety tests and observations before reaching a conclusion about impairment.

What is Walk and Turn Test?

The Walk and Turn Test is a standardized field sobriety test used by law enforcement officers to assess a person’s level of impairment due to alcohol or drugs during a traffic stop. It is one of the three components of the Standardized Field Sobriety Tests (SFSTs) established by the National Highway Traffic Safety Administration (NHTSA).

Here are the key points about the Walk and Turn Test:

1. Divided Attention Test:
   • The Walk and Turn Test is designed to evaluate a person’s ability to divide attention between physical and cognitive tasks, as impaired individuals may struggle with multitasking.
2. Two-Part Procedure:
   • The test consists of two parts – an instructional phase and a walking phase.
3. Instructional Phase:
   • During the instructional phase, the individual is asked to stand with one foot in front of the other, heel to toe, and listen to the officer’s instructions.
4. Demonstration by the Officer:
   • The officer demonstrates the walking part by taking a few steps in a heel-to-toe manner, and the individual is required to watch and remember the instructions.
5. Walking Phase:
   • In the walking phase, the person is instructed to take nine heel-to-toe steps along a straight line, turn in a specific manner, and take nine heel-to-toe steps back.
6. Specific Instructions:
   • The individual must maintain heel-to-toe contact, keep their arms at their sides, and count each step out loud.
7. Observation for Indicators of Impairment:
   • Law enforcement officers observe for specific indicators, including the inability to maintain balance, stepping off the line, using arms for balance, starting before instructed, or making an incorrect turn.
8. Potential Sign of Impairment:
   • Difficulty following instructions, maintaining balance, or completing the test successfully may be considered potential signs of impairment.
9. Not Conclusive Evidence:
   • Like other field sobriety tests, the Walk and Turn Test is not conclusive evidence of intoxication on its own and is part of a broader assessment.
10. Refusal and Legal Consequences:
    • While individuals have the right to refuse the Walk and Turn Test, refusal may lead to legal consequences, such as license suspension.

What is One-Leg Stand Test?

The One-Leg Stand Test is a standardized field sobriety test used by law enforcement officers to assess a person’s level of impairment due to alcohol or drugs during a traffic stop. It is one of the three components of the Standardized Field Sobriety Tests (SFSTs) established by the National Highway Traffic Safety Administration (NHTSA).

Here are the key points about the One-Leg Stand Test:

1. Balance and Coordination Assessment:
   • The One-Leg Stand Test is designed to evaluate an individual’s balance, coordination, and ability to follow instructions, as these can be affected by impairment.
2. Simple Two-Part Procedure:
   • The test consists of a simple two-part procedure: an instructional phase and a balance-maintenance phase.
3. Instructional Phase:
   • During the instructional phase, the person is instructed to stand with one foot approximately six inches off the ground while keeping the raised foot parallel to the ground.
4. Arms at the Sides:
   • The individual is required to keep their arms at their sides and count out loud by thousands (e.g., one thousand-one, one thousand-two) until instructed to stop.
5. Observation for Indicators of Impairment:
   • Law enforcement officers observe for specific indicators, including swaying, hopping to maintain balance, putting the foot down, using arms for balance, or failing to follow instructions.
6. Time Duration:
   • The person is typically asked to maintain this one-legged stance for around 30 seconds.
7. Potential Sign of Impairment:
   • Difficulty maintaining balance, swaying, or other signs of instability may be considered potential indicators of impairment.
8. Not Conclusive Evidence:
   • Similar to other field sobriety tests, the One-Leg Stand Test is not considered conclusive evidence of intoxication on its own and is part of a broader assessment.
9. Refusal and Legal Consequences:
   • While individuals have the right to refuse the One-Leg Stand Test, refusal may have legal consequences, such as license suspension.

What is the Purpose of Field Sobriety Tests?

The primary purpose of Field Sobriety Tests (FSTs) is for law enforcement officers to assess whether a driver is under the influence of alcohol or drugs during a traffic stop. These tests are conducted on the roadside and serve as a tool for officers to gauge a driver’s level of impairment and determine if there is probable cause to believe they are driving under the influence (DUI) or driving while intoxicated (DWI).

The three Standardized Field Sobriety Tests (SFSTs) established by the National Highway Traffic Safety Administration (NHTSA) are designed to be standardized, meaning they have specific procedures and scoring criteria that officers follow. These tests aim to provide a consistent and systematic way for law enforcement to evaluate a driver’s physical and cognitive abilities, helping them make more informed decisions about whether to proceed with further testing or make an arrest.

The specific purposes of each test are as follows:

1. Horizontal Gaze Nystagmus (HGN): To detect the involuntary jerking of the eyes, which may be more pronounced in individuals under the influence of alcohol or certain drugs.
2. Walk and Turn: To assess a person’s ability to follow instructions, maintain balance, and perform a divided attention task, as impairment may affect these skills.
3. One-Leg Stand: To evaluate balance, coordination, and the ability to follow instructions, as impaired individuals may struggle with these tasks.

While the ultimate goal is to enhance road safety by identifying and deterring impaired driving, it’s essential to note that FSTs are not foolproof indicators of intoxication. They are just one part of the overall assessment conducted by law enforcement during a traffic stop. Drivers have the right to refuse FSTs, but refusal may lead to legal consequences, such as license suspension. Understanding the purpose of these tests can help drivers make informed decisions during a traffic stop.

Field Sobriety Tests vs. Roadside Exercises

Field Sobriety Tests (FSTs):

1. Definition:
   • Field Sobriety Tests are a battery of standardized exercises used by law enforcement to assess a person’s level of impairment due to alcohol or drugs during a traffic stop.
2. Purpose:
   • The primary purpose of FSTs is to provide officers with a systematic way to evaluate a driver’s physical and cognitive abilities, helping them determine whether there is probable cause to believe the driver is under the influence and whether further testing or arrest is warranted.
3. Standardization:
   • The National Highway Traffic Safety Administration (NHTSA) has established standardized FSTs, including the Horizontal Gaze Nystagmus (HGN), Walk and Turn, and One-Leg Stand tests.
4. Legal Consequences:
   • Failing FSTs may lead to arrest and can be used as evidence in legal proceedings. Refusal to take FSTs may also have legal consequences, such as license suspension.

Roadside Exercises:

1. Definition:
   • Roadside Exercises, on the other hand, can refer to a broader category of activities or tasks that law enforcement may ask a driver to perform during a traffic stop, not necessarily limited to standardized FSTs.
2. Variability:
   • Roadside exercises may include a range of activities, such as reciting the alphabet, counting, or performing non-standardized physical tasks like touching your nose with your finger.
3. Informal Nature:
   • Unlike FSTs, roadside exercises may not follow a strict set of standardized procedures, and they may vary based on the discretion of the law enforcement officer.
4. Subjectivity:
   • Roadside exercises that are not standardized may be more subjective and open to interpretation, potentially leading to variations in how different officers assess a driver’s performance.

While Field Sobriety Tests are a specific set of standardized exercises, roadside exercises can encompass a broader range of activities that an officer might request during a traffic stop. It’s essential for drivers to be aware of their rights and understand the nature of any tests or exercises requested by law enforcement.

Other Tests

In addition to the well-known standardized Field Sobriety Tests (SFSTs) like the Walk and Turn Test, One-Leg Stand Test, and Horizontal Gaze Nystagmus (HGN), there are various other tests or exercises that law enforcement officers may use during a traffic stop to assess impairment. Some of these additional tests include:

1. Recitation Tests:
   • Reciting the alphabet backward or forward, counting backward, or reciting a series of numbers may be used to assess cognitive function and attention.
2. Finger-to-Nose Test:
   • This test involves closing the eyes and touching the nose with the index finger. It assesses coordination and proprioception.
3. Rhomberg Balance Test:
   • Standing with feet together, head tilted back, and eyes closed, individuals are asked to estimate 30 seconds. Officers observe for swaying or imbalance.
4. Finger Count Test:
   • Counting fingers quickly and accurately when they are shown by the officer tests cognitive function and responsiveness.
5. Hand Pat Test:
   • Patting the hands together in an alternating fashion evaluates coordination and the ability to follow instructions.
6. Preliminary Breath Test (PBT):
   • While not a traditional “field sobriety test,” a PBT is a handheld breathalyzer used to measure blood alcohol content (BAC) at the scene.
7. Romberg Alphabet Test:
   • Reciting the alphabet while standing with feet together, head tilted back, and eyes closed assesses cognitive function and balance.
8. Standing on One Leg with Head Tilt:
   • Similar to the One-Leg Stand Test but with the addition of tilting the head back, challenging balance and coordination.
9. Modified Position of Attention (MPA) Test:
   • Standing with heels together, arms at the sides, and eyes closed, individuals are observed for swaying or loss of balance.
10. Handwriting Test:
    • Writing a simple sentence or the alphabet can be used to evaluate fine motor skills, coordination, and cognitive function.

Factors that Can Affect Field Sobriety Test Performance

Several factors can influence an individual’s performance on Field Sobriety Tests (FSTs), and it’s important to recognize these variables when evaluating test results. Here are key factors that can affect FST performance:

1. Age:
   • Older individuals may naturally have reduced balance and coordination, affecting their ability to perform certain physical tasks.
2. Physical Fitness:
   • General physical health and fitness levels can impact a person’s agility and balance during FSTs.
3. Medical Conditions:
   • Certain medical conditions, such as neurological disorders or injuries, can affect motor skills and coordination.
4. Footwear:
   • Wearing uncomfortable or inappropriate footwear may hinder a person’s ability to perform tasks like walking heel-to-toe or standing on one leg.
5. Surface Conditions:
   • Uneven or slippery surfaces, common during roadside stops, can challenge anyone’s balance and impact test results.
6. Mental Health:
   • Anxiety, stress, or mental health conditions can affect cognitive function, potentially impacting the ability to follow instructions during FSTs.
7. Prescription Medications:
   • Some prescription medications may cause drowsiness, dizziness, or impair cognitive and motor functions, influencing FST performance.
8. Weather Conditions:
   • Harsh weather conditions, such as strong winds or heavy rain, can create challenging environments for FSTs.
9. Nervousness:
   • The stress and nervousness associated with a traffic stop can affect a person’s performance, even if they are not under the influence.
10. Individual Differences:
    • People naturally have varying levels of coordination and balance, and what might be challenging for one person may not be for another.
11. Inadequate Instructions:
    • Unclear or confusing instructions from law enforcement officers can contribute to difficulties in performing FSTs correctly.
12. Improper Administration:
    • Law enforcement officers must administer FSTs according to standardized procedures. Deviations from these procedures can impact the accuracy of the tests.
13. Language Barriers:
    • Language differences may lead to misunderstandings, affecting the individual’s ability to follow instructions during FSTs.
14. Fatigue:
    • Tiredness or fatigue can mimic the effects of impairment and impact a person’s ability to perform well on FSTs.

Your Rights During Field Sobriety Tests

1. Right to Refuse:
   • You have the right to refuse to take Field Sobriety Tests without facing immediate legal consequences. However, refusal may result in other implications, such as license suspension.
2. Voluntary Nature:
   • FSTs are generally voluntary, and law enforcement should inform you that participation is not mandatory. You can choose whether or not to comply.
3. Non-Obligation:
   • Participation in FSTs is not a legal requirement, and you can exercise your right to decline without admitting guilt or facing automatic penalties.
4. Legal Consequences of Refusal:
   • While you have the right to refuse FSTs, there may be legal consequences, such as license suspension or other administrative penalties, depending on your jurisdiction.
5. Right to Legal Representation:
   • If you are arrested or taken into custody based on FST results, you have the right to legal representation. It is advisable to consult with an attorney before answering questions or providing statements.
6. Right to Remain Silent:
   • You have the right to remain silent during questioning, including providing information related to FSTs. You can politely decline to answer questions that may incriminate you.
7. No Self-Incrimination:
   • FSTs are designed to assess physical and cognitive abilities, but participating may provide evidence that could be used against you. You have the right to avoid self-incrimination.
8. Requesting Clarification:
   • If you do choose to participate in FSTs, you have the right to ask for clear and understandable instructions. Misunderstandings due to unclear instructions may impact the accuracy of the tests.
9. Observation of Rights:
   • Law enforcement officers must respect your constitutional rights during the FST process, including the right to refuse tests and the right to legal representation.
10. Documenting the Stop:
    • If you decide not to participate in FSTs, you may consider documenting the traffic stop by taking note of the date, time, location, and names or badge numbers of the officers involved.

Common Misconceptions About Field Sobriety Tests

1. Misconception: Failing FSTs Guarantees Guilt
   • Reality: FSTs are subjective and not foolproof indicators of impairment. Many factors, including medical conditions and nervousness, can affect performance.
2. Misconception: FSTs Are Mandatory
   • Reality: FSTs are generally voluntary, and you have the right to refuse them. However, refusal may have legal consequences such as license suspension.
3. Misconception: Perfect Performance Equals Sobriety
   • Reality: Even sober individuals can find FSTs challenging due to their subjective nature and reliance on coordination and balance.
4. Misconception: Refusal Equals Automatic Guilt
   • Reality: While refusal may result in administrative penalties, it doesn’t automatically imply guilt. It’s a legal choice, and you still have rights.
5. Misconception: FSTs Have High Accuracy Rates
   • Reality: FSTs have inherent limitations and accuracy varies. They are just one part of the assessment, and environmental factors can impact results.
6. Misconception: Officer Opinions Are Absolute
   • Reality: Officers’ interpretations of FSTs are subjective, and their opinions may be challenged in court. Legal defense can question the validity of the tests.
7. Misconception: Only Impaired Individuals Fail FSTs
   • Reality: Various factors, such as age, physical condition, or nervousness, can lead to difficulties in performing FSTs, even for sober individuals.
8. Misconception: FSTs Are Standardized Across Jurisdictions
   • Reality: While NHTSA establishes guidelines, specific procedures may vary between jurisdictions. Familiarity with local laws is crucial.
9. Misconception: FST Results Are Always Admissible in Court
   • Reality: Legal defense can challenge the admissibility of FST results, especially if they were improperly administered or the officer deviated from procedures.
10. Misconception: All FSTs Are Equal in Evidentiary Value
    • Reality: Some FSTs are considered more reliable than others. The Horizontal Gaze Nystagmus (HGN) test, for instance, is often given more weight.
11. Misconception: FSTs Can Differentiate Between Alcohol and Drugs
    • Reality: FSTs cannot specifically identify the substance causing impairment; additional testing is needed for accurate determination.

How to pass field sobriety test?

While the most effective way to “pass” a Field Sobriety Test (FST) is to avoid consuming alcohol or drugs before driving, there are general tips to help you perform well if you find yourself subjected to these tests during a traffic stop:

1. Stay Calm:
   • Remain calm and focused. Anxiety or nervousness can sometimes be misinterpreted, so take deep breaths and concentrate on the instructions.
2. Listen Carefully:
   • Pay close attention to the officer’s instructions. Ask for clarification if something is unclear before you begin the tests.
3. Follow Instructions:
   • Strictly follow the instructions provided. Perform the tasks exactly as instructed, maintaining attention to detail.
4. Maintain Balance:
   • Focus on maintaining your balance during tasks like the Walk and Turn or the One-Leg Stand. Keep your movements deliberate and controlled.
5. Cooperate:
   • Cooperate with the officer within the bounds of your rights. Refusing the FSTs might have legal consequences, so consider your decision carefully.
6. Inform About Medical Conditions:
   • If you have any medical conditions that might affect your performance, calmly inform the officer before the tests begin.
7. Be Mindful of Footwear:
   • Wear sensible footwear, especially if you know you might be asked to perform tasks that involve walking. Unstable or uncomfortable shoes can impact your balance.
8. Stay Sober:
   • The most foolproof way to pass FSTs is to abstain from alcohol or drugs before driving. If you are not impaired, the chances of successfully completing the tests increase significantly.
9. Practice Sobriety:
   • If you have concerns about FSTs, practice sobriety in your everyday activities. This can help enhance your coordination and balance.
10. Document the Stop:
    • If you decide to participate in FSTs, document the details of the traffic stop for your records. This can be valuable if you need to contest the results later.

Remember that FSTs are subjective, and various factors can influence the outcome. However, being cooperative, attentive, and informed about your rights can contribute to a more favorable performance during these tests if you ever encounter them during a traffic stop.

What happens if you pass a field sobriety test?

If you pass a Field Sobriety Test (FST), it generally indicates that, based on the officer’s assessment, you demonstrated the physical and cognitive abilities expected of a sober individual. Here’s what typically happens when you pass an FST:

1. No Immediate Arrest:
   • Passing an FST often means that there are no apparent signs of impairment according to the officer’s evaluation. In such cases, the likelihood of immediate arrest for driving under the influence (DUI) or similar charges is significantly reduced.
2. Continuation of the Traffic Stop:
   • If you pass the FST, the traffic stop may continue for routine matters, such as checking your license and registration. However, the focus on impairment may diminish.
3. Consideration of Other Factors:
   • Law enforcement may consider other factors, such as the reason for the traffic stop, your behavior, and any other observable signs of impairment before deciding whether to proceed with further testing or to let you go.
4. Possibility of Additional Tests:
   • Even if you pass the FST, officers may choose to administer additional tests or assessments based on their observations or suspicions. This could include a preliminary breath test or other evaluations.
5. Completion of the Traffic Stop:
   • If there are no additional indicators of impairment and you successfully navigate any further tests, the traffic stop may conclude without further legal action related to DUI charges.

While passing an FST is a positive outcome, it does not guarantee immunity from other legal consequences, and officers may still take other factors into consideration. Additionally, refusing to take the FST might have legal consequences, such as license suspension, depending on local laws.