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What to Expect From Field Sobriety Tests in Illinois

Field sobriety tests are common tools used by law enforcement in Illinois to determine if a driver is under the influence of alcohol or drugs. These tests typically include a series of physical and cognitive exercises such as the horizontal gaze nystagmus (HGN) test, the walk-and-turn, and the one-leg stand.

While these tests are designed to assess impairment, it's important to understand that they can be subjective and are not infallible. The results can be influenced by a variety of factors unrelated to alcohol consumption, such as physical disabilities, medications, or even nervousness. Knowing what to expect during these tests and the implications of their outcomes is crucial for any driver.

If you're facing a DUI charge based on the results of field sobriety tests, or if you're concerned about your rights during such evaluations, it's essential to seek legal guidance. An experienced McHenry County DUI attorney can provide you with valuable information on how these tests should be conducted, their potential inaccuracies, and how to challenge their results in court.

Contact our law firm today at (847) 999-7616 to discuss your case with a skilled attorney who can help protect your rights and guide you through the complexities of DUI proceedings in Illinois. Don't navigate this challenging situation alone—let us advocate for you and ensure the best possible outcome.

The Walk And Turn Test

The Walk and Turn test is one of the standardized field sobriety tests used by law enforcement to assess whether a driver is impaired. This test is designed to measure a person’s ability to complete tasks requiring physical and mental concentration simultaneously, as impairment by alcohol or other substances can hinder one's ability to do so.

Here’s how the Walk and Turn test is typically administered:

Instruction Stage

The officer instructs the suspect to stand in a heel-to-toe position with their arms at their sides and listen to instructions without starting the test until told to do so. This initial position is crucial as it tests the suspect's ability to balance and follow directions.

Demonstration and Explanation

The officer explains the tasks of the test. The suspect is instructed to take nine heel-to-toe steps along a straight line. While doing this, they must keep their arms at their sides, watch their feet, and count each step out loud.

Turning Phase

After completing the nine steps, the suspect must turn on one foot and return in the same manner in the opposite direction. The officer will demonstrate how to make the turn, which involves keeping the front foot on the line and turning by taking a series of small steps with the other foot.


The officer observes the suspect throughout the performance of the test. The criteria they look for include whether the suspect can keep balance while listening to the instructions, begins before the instructions are finished, stops while walking to regain balance, does not touch heel-to-toe, steps off the line, uses arms to balance, makes an improper turn, or takes an incorrect number of steps.

a man performing a walk and turn test for a police officer

If the suspect displays two or more of these indicators, it is typically considered a sign of impairment. The Walk and Turn test is reported to be accurate in classifying individuals as impaired about 68% of the time, according to research sponsored by the National Highway Traffic Safety Administration (NHTSA).

It's important to note that while the Walk and Turn test is a commonly used tool in DUI stops, it's not foolproof. Factors such as age, weight, footwear, road conditions, and natural balance issues can affect performance. If you've been stopped and subjected to a Walk and Turn test and feel it was improperly conducted or unfairly evaluated, contacting a skilled DUI attorney can help protect your rights and potentially challenge the test results.

The Horizontal Gaze Test

The Horizontal Gaze Nystagmus (HGN) test is one of the three standardized field sobriety tests in Illinois police officers use to determine if a suspect is impaired by alcohol or other substances. Nystagmus is an involuntary jerking of the eyeball, which can become exaggerated due to impairment from alcohol consumption or certain other substances. The test is based on the premise that alcohol and certain other drugs can hinder the brain’s ability to correctly control eye muscles, thus causing the jerking motion.

Here’s how the Horizontal Gaze Nystagmus test is typically administered:

Explanation and Positioning

The officer explains the test to the subject. The suspect is instructed to stand straight, hold their head still, and follow an object only with their eyes. The object could be a small flashlight, a pen, or the tip of a penlight, held about 12 to 15 inches from the suspect’s face and slightly above eye level.

Checking for Nystagmus at Rest

Before starting the test, the officer checks the suspect’s eyes to ensure there is no nystagmus at rest (when the eyes are looking straight ahead) and that the pupil sizes are equal.

Smooth Pursuit

The officer moves the object slowly from side to side and observes the eyes of the suspect as they follow the moving object. The officer is checking for a lack of smooth pursuit in the eyes, which normally glide smoothly like a marble rolling over a smooth pane of glass. Impairment may cause the eye to twitch or jerk.

Distinct Nystagmus at Maximum Deviation

The officer then moves the object to the far left and right, holding it at maximum deviation for at least four seconds. The officer observes if there is distinct nystagmus when the eye is at maximum deviation. In an unimpaired person, the eye should be able to hold steady at this position.

Onset of Nystagmus Prior to 45 Degrees

The key part of the test involves moving the object at a pace that would take about four seconds for the eye to move from center to side. Officers look for the point at which the eye begins to exhibit nystagmus. If the nystagmus begins before the eye reaches a 45-degree angle, it suggests impairment.

a police officer administering a horizontal gaze test for a man

The HGN test is considered to be the most reliable field sobriety test when administered properly. According to the National Highway Traffic Safety Administration (NHTSA), the presence of four or more clues between the two eyes after administering the HGN test is a strong indicator of a blood alcohol concentration (BAC) of 0.08% or greater.

While the HGN test is a common tool used during DUI stops, its results can be contested in court. Factors such as environmental conditions, natural nystagmus, neurological issues, eye problems, or even improper administration by the officer can all affect the results of the test. If you believe the HGN test was incorrectly conducted or interpreted, consulting with a knowledgeable DUI attorney can help you understand your rights and potentially challenge the evidence.

The One-Leg Stand Test

The One-Leg Stand test is a commonly used field sobriety test that helps law enforcement officers determine if a person is impaired by alcohol or drugs. The test assesses the individual's balance, coordination, and ability to follow directions—all of which can be compromised under the influence of alcohol.

Here’s how the One-Leg Stand test is typically administered:

Instruction Phase

The officer will explain and demonstrate the test. The suspect is instructed to stand with their feet together and arms at their sides while the instructions are given. This helps the officer observe the suspect's balance during the explanation.

Performance Phase

The suspect is asked to raise one foot, either foot, approximately six inches off the ground, keeping the raised foot parallel to the ground.

The suspect must then count aloud by thousands ("one thousand-one, one thousand-two, etc.") until told to stop. This typically lasts for 30 seconds, which the officer times.

Throughout the test, the suspect must keep their arms at their sides, watch the raised foot, and count as instructed without using their arms to balance.

Officer’s Observations

The officer observes the suspect for signs of impairment, including:

  • Swaying while balancing: Swaying from side to side or back and forth while trying to maintain balance.
  • Using arms to balance: Raising arms more than six inches from the sides of the body to maintain balance.
  • Hopping: Using the foot on the ground to hop around to maintain balance.
  • Putting the foot down: Place the raised foot down one or more times during the 30-second count.

According to the National Highway Traffic Safety Administration (NHTSA), if a suspect exhibits two or more of the observation clues, it suggests impairment and that there could be a high likelihood of the suspect's blood alcohol concentration (BAC) being 0.08% or greater. The One-Leg Stand test is considered a "divided attention" test that assesses both the suspect's balance and ability to concentrate on two tasks simultaneously.

Like other field sobriety tests, the One-Leg Stand test is subjective and can be influenced by various factors including age, weight, footwear, road surface, weather conditions, and inherent coordination abilities. If you are facing a DUI charge based on your performance in a One-Leg Stand or other field sobriety tests, it is crucial to seek legal representation. An experienced DUI attorney can challenge the conditions and administration of the test, potentially questioning the reliability of the results in your case.

Can You Refuse a Field Sobriety Test?

In Illinois, you have the legal right to refuse to participate in field sobriety tests without facing direct legal penalties such as fines or additional criminal charges for the refusal itself. Unlike chemical tests (breath, blood, or urine tests), which have specific penalties attached to refusal under implied consent laws, refusing field sobriety tests does not automatically trigger a statutory penalty such as license suspension.

a man being pulled over for suspicion of DUI

However, there are still some considerations to keep in mind if you choose to refuse these tests:

  1. Arrest Possibility: While you can refuse field sobriety tests without direct legal penalties, refusal can still be used by an officer as part of their overall assessment of your impairment. This means that if the officer has other evidence of intoxication (such as erratic driving, the smell of alcohol, or visible open containers), they may still arrest you for DUI based on that evidence alone.
  2. Court Implications: Refusal to perform field sobriety tests may also be mentioned in DUI court, and prosecutors might use it to suggest that you refused because you knew you would fail the tests. However, an experienced DUI attorney can argue against this interpretation and help mitigate how much weight this refusal carries in court.
  3. Driver's License Issues: For chemical tests (breathalyzer, blood, urine), Illinois' implied consent law means that refusal can lead to automatic license suspension and other penalties. It’s important to distinguish this from field sobriety tests, which do not fall under implied consent laws.

If you are stopped for suspected DUI and are considering whether to submit to field sobriety tests, it is crucial to understand these nuances. Many people choose to refuse these tests because they can be subjective and difficult to perform perfectly, even for sober individuals, particularly under stressful conditions.

Given the complexities surrounding DUI stops and the consequences of any decision made during such an encounter, consulting with a qualified DUI attorney as soon as possible can provide guidance and help protect your rights. If you find yourself in a situation involving a DUI stop or charges, consider reaching out to a skilled attorney who can advise you on the best course of action based on your specific circumstances.

What To Do If You Fail A Field Sobriety Test?

If you fail a field sobriety test during a traffic stop, it can be a stressful and daunting experience, but it's important to know how to proceed to protect your legal rights. Here are some steps you should consider:

  1. Stay Calm and Polite: Regardless of the test results, remain calm and respectful towards the officer. Agitation or confrontation can complicate the situation and potentially be used against you in court.
  2. Do Not Admit Guilt: Avoid making any statements that could be interpreted as admissions of guilt, such as apologizing or providing explanations for your performance on the test. Politely decline to answer questions about how much you've drunk or any other inquiries that could incriminate you. You have the right to remain silent, and it's often best to use it until you can speak with an attorney.
  3. Decide on Chemical Testing: You may be asked to undergo chemical testing (breath, blood, or urine test) after failing field sobriety tests. In Illinois, due to implied consent laws, refusing such tests can result in automatic license suspension and other penalties. Be aware that the consequences for refusing these tests are typically more severe than for failing them.
  4. Document Everything: As soon as possible, write down everything you remember about the stop, the tests, and any other interactions with the police. Note the time of day, weather conditions, how the tests were administered, and any other factors that could affect your performance on the sobriety tests or the officer's observations.
  5. Seek Legal Representation: Contact a DUI attorney as soon as you can. An experienced lawyer can provide critical guidance, help you understand your rights, and represent you in any legal proceedings. They can challenge the validity of the field sobriety tests, explore deficiencies in how the tests were administered, and counter the prosecution's arguments based on a variety of legal defenses.
  6. Prepare for Possible Consequences: Depending on the circumstances and your history, consequences could include fines, license suspension, or even jail time. An attorney can help you navigate the legal system and work towards minimizing these penalties.
  7. Consider DUI Education and Rehabilitation Programs: In some cases, participating in DUI education or rehabilitation programs can be part of a legal strategy to mitigate penalties or demonstrate to the court your commitment to responsible behavior.

Failing a field sobriety test does not automatically mean you will be convicted of a DUI. These tests are subjective and can be influenced by many factors unrelated to alcohol consumption. An attorney skilled in DUI defense can challenge these results effectively and advocate on your behalf. If you’ve failed a field sobriety test, getting legal assistance is the most proactive step you can take toward a favorable resolution of your case.

Do You Need Help With a DUI Charge?

If you find yourself in the challenging situation of having failed or refused a field sobriety test, it's important to understand that you still have legal options and rights that can be exercised. A knowledgeable DUI attorney plays a critical role in navigating these complex situations. They can provide invaluable assistance by examining the circumstances of your arrest, challenging the administration and results of the sobriety tests, and developing a robust defense strategy based on the specifics of your case.

An experienced Illinois DUI lawyer can question the subjective nature of field sobriety tests and argue for the potential inaccuracies caused by external factors such as medical conditions, improper instructions, or environmental conditions.

Facing DUI charges can have significant repercussions on your life, but you don’t have to go through it alone. Contact our law firm today to schedule a consultation with a seasoned DUI attorney who will advocate for your rights and aim to achieve the best possible outcome in your case. Don't let one moment define your future—let us help you fight for a fair and just resolution.

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