One Leg Stand Test: Guide to DWI Sobriety Testing

The One Leg Stand test: What you need to know

Imagine you’re driving home one evening when you see the flashing lights of a police car signaling you to pull over. If the officer suspects you’re under the influence of alcohol or drugs, you might be asked to perform a field sobriety test. One such test is the One Leg Stand test, which can be a significant DWI assessment in Durham, NC.

This blog post delves into the intricacies of the One Leg Stand test, providing helpful information about its procedures, possible DWI Lawyer Near Me Durham NC legal implications, and how it fits into the broader spectrum of DUI enforcement.

Whether you’re a driver looking to stay informed or someone curious about NC DUI laws, this guide reviews the nuances of the OLS – One Leg Stand test, particularly as it relates to probable cause for arrest and use as evidence of impairment in court.

What is the One Leg Stand Test?

The One Leg Stand test or “OLS,” is a standardized field sobriety test used by law enforcement officers to help determine whether a driver is impaired.

During the test, someone suspected of “drunk driving” is asked to stand with one foot approximately six inches off the ground and count aloud by thousands (one thousand-one, one thousand-two, etc.) until told to put the foot down.

This test typically lasts approximately 30 seconds.

Officers watch for signs of impairment, such as swaying, hopping, or using arms to balance, which could indicate possible impairment – Cole Williams, Durham DWI Lawyer 

The One Leg Stand test is part of a trio of tests recommended by the National Highway Traffic Safety Administration (NHTSA) in identifying possible indicators of impairment.

It’s designed to assess the balance, attention, and physical control of an individual, which can be compromised under the influence of alcohol or drugs.

The Role of Sobriety Tests in DUI Stops

Sobriety tests often play a pivotal role during DUI (Driving Under the Influence) stops. In North Carolina, the offense is referred to as “impaired driving” in N.C.G.S. 20-138.1.

While there are references in the North Carolina DWI laws to being under the influence of an impairing substance, the law does not specifically refer to the commonly used terms of DUI or DWI or even “drunk driving.”

It really doesn’t much matter if you call it DUI or DWI, we understand what clients are talking about when they call for help – Cole Williams, Durham Lawyer 

Standardized Field Sobriety Tests or “SFSTs” provide on-the-spot evidence of impairment that can support an officer’s decision to arrest a driver for DUI.

Arrests in North Carolina must be supported by something called Probable Cause to Arrest.

In Durham NC, as in the rest of the country, “failing” a field sobriety test like the One Leg Stand can lead to further testing, such as breathalyzers or blood tests, and potentially a DUI charge.

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While breathalyzers and blood tests quantify the amount of alcohol or drugs in the system, field sobriety tests attempt to assess how those substances affect a person’s physical and cognitive abilities.

How to Perform the One Leg Stand Test

To perform the One Leg Stand test correctly, an individual must follow the officer’s instructions closely.

The person will be asked to:

  1. Stand with feet together and arms at the side.
  2. Lift one foot, either foot, approximately six inches off the ground.
  3. Keep the lifted foot parallel to the ground.
  4. Look at the elevated foot.
  5. Count aloud in the manner specified by the officer (usually by thousands).
  6. Continue until told to stop by the officer.

This test demands both physical control to maintain balance and mental focus to count out loud simultaneously.

That can be significantly harder if the suspect is appreciably impaired.  

Indicators of Impairment in the One Leg Stand Test

During the One Leg Stand test, officers look for specific indicators of impairment. These include:

  • Swaying while balancing: An inability to maintain a steady posture without swaying side to side or back and forth.
  • Using arms for balance: Raising arms more than six inches from the sides of the body to avoid falling over.
  • Hopping: Resorting to hopping on the foot that remains on the ground to maintain balance.
  • Putting the foot down: Placing the lifted foot down before the time is completed.

Using the NHTSA protocols, the presence of two or more of these indicators may serve as evidence of impairment.

The criteria are based on research conducted by the NHTSA, which sets forth that individuals with a blood alcohol concentration (BAC) of 0.08% or higher may have difficulty with the test.

Accuracy and Reliability of the One Leg Stand Test

The One Leg Stand test, along with the other standardized field sobriety tests endorsed by the NHTSA, has been subjected to research to verify its accuracy and reliability.

DWI defense lawyers may refer to those as the “verification studies.”

When administered properly, the One Leg Stand test is capable of identifying signs of appreciable impairment and impaired drivers, but, it is not a perfect test – Cole Williams, Durham Attorney 

It’s essential to note that factors such as age, weight, physical conditions, and even footwear can influence an individual’s performance on this test.

Therefore, while a commonly used tool in the field by police officers investigating possible impairment, the test is not infallible.

Legal Implications of the One Leg Stand Test

The results of a One Leg Stand test can significantly impact a DUI case in Durham, NC.

If an individual “fails” the test, that could be used as probable cause for arrest and as evidence in court. DWI charges in Durham

However, it’s crucial for drivers to understand that field sobriety test results are just one component of a DUI case.

Other evidence, including breathalyzer results, officer observations, and traffic violations, should also considered.

In some instances, and when legally appropriate, people facing DWI charges may be able to challenge the administration or interpretation of the One Leg Stand test in court.

Factors such as improper instructions, uneven testing surfaces, and non-alcohol-related balance issues can affect the test’s outcome and may be grounds for contesting the results in certain factual scenarios.

Each case is different, just like each person charged with DWI in Durham.  If you have questions about your individual case, it’s a good idea to immediately consult with an experienced attorney.

Challenges and Controversies Surrounding the One Leg Stand Test

The One Leg Stand test, while widely used, is not without its critics.

Concerns may arise regarding its fairness and accuracy.

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For example, individuals with certain medical conditions, disabilities, or even those who are older and have less physical agility, may struggle with the test under sober conditions.

Furthermore, environmental factors such as poor lighting, uneven road surfaces, or adverse weather conditions can also affect performance.

Critics argue that such factors can lead to false positives, where sober individuals are mistakenly identified as impaired.

Additionally, the subjective nature of the test—relying on an officer’s interpretation of performance—can lead to inconsistencies.

Different officers may judge the same performance differently, raising concerns about the test’s objectivity.

One Leg Stand Test vs. Other Sobriety Tests

The One Leg Stand test is just one of three standardized field sobriety tests recommended by the NHTSA.

The other two are the Horizontal Gaze Nystagmus (HGN) test, which involves following an object with the eyes to check for involuntary jerking movements, and the Walk-and-Turn test, which assesses the ability to walk a straight line and turn while following instructions.

Each test targets different physical and cognitive faculties affected by alcohol and drug use.

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The One Leg Stand focuses on balance and coordination; the HGN test examines eye movement control, and the Walk-and-Turn evaluates the ability to perform tasks requiring attention, balance, and precise movements.

Together, these tests may provide an assessment of impairment, though each has its limitations and susceptibility to external factors.

Alternatives to Field Sobriety Tests

In addition to field sobriety tests, law enforcement may use breathalyzers and blood tests to determine impairment levels.

These tests can provide a more objective measure of blood alcohol concentration (BAC).

While field sobriety tests assess the physical and cognitive effects of impairment, breathalyzers and blood tests quantify the amount of alcohol in the system, offering concrete evidence that can be used in court.

While very commonly referred to as a “breathalyzer” by the public, the roadside, handheld breath screening device is technically called an “AlcoSensor.”

The evidentiary breath testing machine is known as the Intoximer EC/IR II.

Even though we haven’t used the actual ‘breathalyzer machine’ for more than 25 years in North Carolina, just about everyone still calls all breath testing devices, whether the handheld one on the side of the road or the one at the jail, a ‘breathalyzer’ – Cole Williams, DWI Defense Attorney   

Understanding Field Sobriety Test Procedures

If you’ve been charged with DUI in Durham, it’s essential to have a comprehensive understanding of field sobriety test procedures, including the One Leg Stand test.

Here, we’ll dive deeper into various aspects of the test and its broader implications.

Administering the One Leg Stand Test

The One Leg Stand test may seem straightforward, but its proper administration is critical to obtaining accurate results.

Law enforcement officers are trained to follow specific protocols when conducting this test:

  1. Standardized Instructions: Officers are trained to provide standardized instructions to ensure consistency across different tests. Deviating from these instructions can lead to skewed results.
  2. Demonstration: Typically, the officer will partially demonstrate the One Leg Stand test before asking the individual to perform it. This demonstration serves to clarify the expected actions.
  3. Counting: The officer should instruct the individual to count aloud by thousands, often starting from one thousand-one. This counting serves multiple purposes. It helps assess the individual’s ability to follow instructions and maintain cognitive focus while performing a physical task.
  4. Observation: Throughout the test, the officer closely observes the individual’s actions, looking for possible signs of impairment as previously discussed. A meticulous and fair assessment can be crucial to the test’s accuracy.
  5. Time Duration: The test usually lasts for 30 seconds, but the officer can terminate it earlier if they observe enough indicators of impairment. This termination is at the officer’s discretion.

Understanding these procedural details is essential, especially if you find yourself subjected to a One Leg Stand test.

It can help you evaluate whether the test was conducted correctly and whether any deviations from the standardized procedures might be used in your defense.

Challenging the One Leg Stand Test

As mentioned earlier, challenges and controversies surround the One Leg Stand test.

It’s important to be aware of potential issues that can affect the test’s accuracy:

  1. Medical Conditions: Individuals with certain medical conditions, such as inner ear disorders or musculoskeletal issues, may struggle with balance despite being completely sober. Communicating such conditions with the officer before the test can be crucial.
  2. Environmental Factors: Environmental conditions, such as uneven or slippery surfaces, poor lighting, flashing strobe lights, or adverse weather, can influence test performance. If the testing environment was less than ideal, it could be a point of contention in your defense.
  3. Footwear: The type of footwear you are wearing can impact your ability to balance during the test. High heels or shoes with inadequate support may make it more challenging to maintain balance.
  4. Nervousness: Nervousness during a DUI stop is common, and it can affect your ability to perform the test even if you are entirely sober. It’s essential to stay as calm as possible, though this can be easier said than done in a stressful situation.
  5. Officer Subjectivity: The One Leg Stand test’s subjectivity is a significant concern. Different officers may interpret the same performance differently, leading to inconsistencies. If you believe the officer’s judgment was biased or unfair, it may be worth discussing with your legal counsel.

Implications of Failing the One Leg Stand Test

“Failing” the One Leg Stand test can have serious consequences.

It can serve as a factor in determining probable cause for arrest and may be used as evidence against you in court.

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Understanding the legal implications is, therefore, a good idea:

  1. Probable Cause: A failed One Leg Stand test, together with other NHTSA sobriety tests and possible indicators of impairment, could give the officer probable cause to arrest you for DUI. This means you could be taken into custody, and further testing, such as breathalyzers or blood tests, may be administered.
  2. Court Evidence: The results of the One Leg Stand test are often presented as evidence in court during a DUI trial. This evidence can significantly impact the outcome of your case, making it essential to consider the factors discussed earlier if you believe the test was administered unfairly.

The Subjectivity of Field Sobriety Tests

Subjectivity is a recurring theme in field sobriety tests, including the One Leg Stand test.

An officer’s judgment plays a significant role in evaluating your performance.

This subjectivity can lead to challenges and debates in DUI cases. Here are some factors to consider:

  1. Officer Training: Officers receive training in administering and evaluating field sobriety tests. However, the quality and consistency of this training can vary. Some officers may be more experienced or better trained than others, leading to differences in how they conduct and interpret the tests.
  2. Influence of Bias: Human bias can impact an officer’s judgment. Unconscious biases related to age, race, or other factors can inadvertently affect how an officer perceives your performance during the One Leg Stand test. Awareness of these biases is crucial in ensuring a fair evaluation.
  3. Objective vs. Subjective Evidence: While breathalyzers and blood tests provide more objective evidence of impairment, field sobriety tests rely on an officer’s subjective assessment. This subjectivity leaves room for interpretation and potential discrepancies in the results.
  4. Legal Challenges: Given the subjectivity of field sobriety tests, legal challenges are not uncommon. Defendants may, in certain circumstances, argue that the test was improperly administered, or their performance was influenced by external factors, leading to an inaccurate evaluation.
  5. Legal Counsel: If you are facing DUI charges based on the results of a One Leg Stand test or any other field sobriety test, it’s essential to consult with an experienced DUI attorney. They can assess the circumstances of your case, including the administration of the test, and determine whether there are grounds for a legal challenge.

The Horizontal Gaze Nystagmus (HGN) Test

The HGN test is designed to detect involuntary jerking movements of the eyes, known as nystagmus, which can be exacerbated by alcohol or drug impairment.

During this test, the officer will ask you to follow an object, such as a pen or flashlight or the officer’s finger, with your eyes while keeping your head still.

The officer will observe your eye movements for any signs of nystagmus.

Key points about the HGN test:

  • Subjective Measure: Like the One Leg Stand, the HGN test relies on a subjective measure of impairment as it focuses on a physiological response (nystagmus).
  • Accuracy: When administered correctly, the HGN test can be an accurate measure of possible impairment.
  • Limitations: The HGN test requires proper training and careful administration. Factors such as lighting conditions and the officer’s experience can influence the results.

The Walk-and-Turn Test

The Walk-and-Turn test assesses your ability to follow instructions while performing a divided attention task.

You are asked to take nine heel-to-toe steps along a straight line, turn in a specific manner, and take another nine heel-to-toe steps back.

The officer observes your ability to maintain balance, follow instructions, and perform the task accurately.

Key points about the Walk-and-Turn test:

  • Divided Attention: This test evaluates your ability to divide your attention between physical actions and listening to instructions, making it a valuable tool in assessing impairment.
  • Objective Measures: While it relies on subjective judgment to some extent, the Walk-and-Turn test involves numerous possible “clues of impairment,” such as whether you stepped off the line or failed to maintain balance.
  • Proper Administration: Like all field sobriety tests, proper administration is crucial for accurate results. Factors like uneven terrain or unclear instructions can affect your performance.

Comprehensive Assessment of Impairment

Combining the One Leg Stand test with the HGN test and the Walk-and-Turn test allows the opportunity for law enforcement to obtain a more comprehensive assessment of impairment.

By targeting different aspects of physical and cognitive function, these tests can provide a more holistic view of an individual’s sobriety.

It’s important to note that while these tests are commonly used law enforcement, they are not infallible.

Factors such as medical conditions, environmental variables, and subjectivity in evaluation can influence the results.

This is why it’s smart to have legal representation if you are facing DUI charges in Durham, North Carolina based on field sobriety tests.

Tips for Individuals Undergoing the One Leg Stand Test

If you’re ever asked to perform the One Leg Stand test, consider these tips:

  1. Listen carefully: Understand the instructions fully before beginning the test. Ask the officer to clarify anything you don’t understand.
  2. Focus on a fixed point: Keep your eyes on your lifted foot or another fixed point to help maintain balance. Avoid looking around, as this can affect your stability.
  3. Stay calm: Nervousness can affect your balance and concentration, so try to remain as calm as possible. Take deep breaths and focus on the task at hand.
  4. Communicate: If you have a condition that might affect your performance, inform the officer beforehand. They may take your condition into consideration or choose alternative tests if necessary.
  5. Know your rights: Familiarize yourself with your rights during a DUI stop. While you can refuse field sobriety tests, refusal can have legal consequences. Declining to submit to SFSTs may be considered in the “arrest decision” by the charging officer.
  6. Seek legal counsel: If you are arrested for DUI based on field sobriety tests, it’s essential to consult with an experienced DUI attorney. They can assess the circumstances of your case, including the administration of the tests, and build a defense strategy tailored to the unique aspects of your criminal charge.

Alternatives to Field Sobriety Tests

In addition to field sobriety tests, law enforcement may use breathalyzers and blood tests to determine impairment levels.

These tests provide the potential for a more objective measure of blood alcohol concentration (BAC).

While field sobriety tests assess the physical and cognitive effects of impairment, breathalyzers and blood tests quantify the amount of alcohol in the system, offering concrete evidence that can be used in court.

Breathalyzer Tests

Breathalyzer tests are a common method of determining an individual’s BAC during a DUI stop. They work by measuring the concentration of alcohol in a person’s breath, which correlates with their BAC.

The higher the BAC, the more alcohol is detected in the breath.

Key points about breathalyzer tests:

  • Quick Results: Breathalyzer tests provide rapid results, making them convenient for on-the-spot assessments during traffic stops.
  • Objective Measure: BAC levels are quantified, making it a somewhat more objective measure of impairment than field sobriety tests.
  • Calibration: Proper calibration and maintenance of breathalyzer equipment are crucial for accurate results. Improperly calibrated devices can lead to false readings.

Blood Tests

Blood tests involve drawing a blood sample to determine an individual’s BAC.

These tests are often considered highly accurate and are, therefore, commonly used as evidence in DUI cases.

Key points about blood tests:

  • Accuracy: Blood tests are generally considered the most accurate method for determining BAC.
  • Laboratory Analysis: Blood samples are sent to a laboratory for analysis, providing the opportunity for precise results.
  • Time-Consuming: Blood tests take longer to administer and analyze compared to breathalyzer tests.


The One Leg Stand test can be a crucial component of DUI enforcement, providing officers with a quick assessment of a driver’s sobriety.

While it has its limitations and is subject to debate, understanding this test’s role, how it’s administered, and its legal implications may serve to help drivers navigate the complexities of DUI stops more effectively.

Staying informed about your rights and the testing process is key to ensuring fair treatment and making informed decisions on the road.

As always, it’s smart to avoid driving after consuming alcohol or drugs. Safe driving protects not only your safety but also that of others on the road.

For more information on DUI laws in Durham, NC, and additional resources, please visit Durham DWI Defense.  

In summary, the One Leg Stand test is just one piece of the puzzle in DUI enforcement.

It’s essential to be aware of your rights, understand the test’s procedures and limitations, and seek legal counsel if you find yourself facing DUI charges.

The more informed you are, the better prepared you’ll be to navigate the legal process and make informed decisions regarding your defense.


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