Field sobriety tests (FTSs) include three tests that police use to determine whether a driver is impaired. These assessments measure the individual’s balance, coordination, and capacity to manage multiple tasks at the same time.
Scientific studies provide evidence that these tests effectively confirm legal intoxication in about 90% of suspected drunk driving cases when administered by a trained officer. Consequently, the outcomes of these tests are legally admissible as substantiating evidence in judicial proceedings.
However, with an experienced DWI lawyer on your side, you have an advocate to investigate the validity of the tests. Below, we examine the core tests used by officers and how an attorney can challenge the results.
What Is a Field Sobriety Test?
A field sobriety test is a series of physical and cognitive tests conducted by law enforcement officers to assess a driver’s level of impairment due to alcohol or drugs. These tests are typically administered during a traffic stop if an officer suspects a driver of driving under the influence (DUI) or driving while intoxicated (DWI).
The purpose of these tests is to provide the officer with objective evidence of impairment that can be used to establish probable cause for an arrest and to support the prosecution’s case in court. The tests are designed to assess a driver’s balance, coordination, reaction time, and cognitive abilities, which can be affected by the consumption of alcohol or drugs.
The Walk-and-Turn Test
The walk-and-turn test is a common field sobriety test that involves the officer instructing the driver to take nine steps, heel-to-toe, along a straight line, then turn on one foot and return nine steps in the opposite direction. During this test, the officer looks for several indicators of impairment as outlined by the National Highway Traffic Safety Administration (NHTSA):
- Beginning before the instructions are finished.
- Inability to maintain balance while listening to the instructions.
- Failure to touch heel-to-toe with each step.
- Loss of balance while turning.
- Stopping while walking to regain balance.
- Taking an incorrect number of steps.
- Using arms to balance.
According to the NHTSA, if a driver exhibits two or more of these indicators during the walk-and-turn test, there is a 68% likelihood that their blood alcohol concentration (BAC) level is 0.10 or higher.
It is important to note that the walk-and-turn test, like other field sobriety tests, is subjective in nature and can be influenced by various factors unrelated to impairment, such as nervousness, fatigue, physical limitations, or environmental conditions. An experienced attorney can challenge the interpretation of these test results and advocate for a your rights.
Horizontal Gaze Nystagmus
Horizontal gaze nystagmus (HGN) is a natural and involuntary phenomenon characterized by a “jerking” movement of the eyeball when the eyes are rotated to high peripheral angles. This phenomenon occurs in everyone to some extent. However, when a person is intoxicated, the jerking of the eyes becomes more pronounced and can occur at lesser angles.
Intoxication, particularly due to alcohol, can affect the smoothness and control of eye movements. In turn, this causes an exaggerated nystagmus response during an HGN test. When an officer observes a person’s eyes during the HGN test, they may look for the presence and degree of nystagmus to assess potential impairment.
While HGN can indicate the influence of alcohol or certain drugs, there can be other factors that contribute to the presence of nystagmus. These include certain medical conditions or eye-related issues. Additionally, the interpretation of nystagmus can vary based on the expertise and training of the administering officer.
When facing DUI charges based on the results of an HGN test, it is essential to consult with an experienced attorney who can scrutinize the administration of the test, evaluate any potential inaccuracies or biases, and challenge its reliability as evidence of impairment.
One-Leg Stand Test
During the one-leg stand test, the officer instructs the driver to stand with one foot approximately six inches off the ground and count from 1,001 (one-thousand-one, one-thousand-two, and so on) until the officer instructs them to put the foot down. Throughout the next 30 seconds, the officer observes the driver for the following four indicators of impairment:
- Hopping to maintain balance.
- Putting the foot down.
- Swaying while trying to balance.
- Using arms to maintain balance.
According to the National Highway Traffic Safety Administration (NHTSA), if a driver exhibits two or more of these indicators during the one-leg stand test, there is a 65% probability that their blood alcohol concentration (BAC) level is 0.10 or greater.
Can a Sober Person Fail These Tests?
Various factors can contribute to an individual’s inability to successfully perform field sobriety tests. This is true even if they are not under the influence of alcohol or drugs. These factors may include underlying medical conditions, disabilities, advanced age, recent injuries, or the use of specific medications.
For instance, wearing contact lenses during an HGN test could impact the test results.
During a traffic stop, the officer typically asks the driver if there is any reason they might have difficulty performing the tests. It is crucial to provide an honest response and communicate any legitimate reasons that could affect your performance. The officer should document your explanation in the official arrest report.
Mentioning such legitimate reasons for potential test failure can be advantageous when building your defense in court. By having these factors documented in the official record, you can provide evidence that supports your inability to perform the tests accurately due to factors unrelated to impairment.
This information can be helpful for your attorney to challenge the reliability and validity of the field sobriety test results and strengthen your case during legal proceedings.
Challenging Field Sobriety Tests
Field sobriety tests, such as the walk-and-turn, one-leg stand, and horizontal gaze nystagmus (HGN) tests, are subjective assessments administered by law enforcement officers during traffic stops. The tests are intended to provide objective evidence of impairment. However, there are numerous factors that can affect an individual’s performance, leading to inaccurate conclusions.
Nervousness and Anxiety
Being pulled over by law enforcement can naturally induce anxiety and nervousness. These impact a person’s ability to perform the tests accurately. Sweating palms, a racing heart, and heightened stress levels can mimic the physical indicators of impairment, leading to false positives.
Field sobriety tests assume that all individuals are physically capable of performing the requested tasks. However, many individuals may have medical conditions, injuries, or disabilities that affect their balance, coordination, and ability to comply with the test instructions. These limitations can unjustly skew the test results against them.
The environment in which field sobriety tests are conducted can significantly impact their accuracy.
- Poor lighting
- uneven terrain
- adverse weather conditions
- distracting noises
- passing traffic
All of these factors introduce additional challenges that affect a person’s performance, even if they are sober.
Officer Bias and Subjectivity
These tests rely heavily on the interpretation and judgment of the administering officer. Unfortunately, subjective factors such as personal bias, inadequate training, or improper administration can lead to incorrect conclusions.
Can I Refuse an FST?
It is important to understand that you have the right to refuse a field sobriety test. However, there can be consequences imposed by the state for doing so.
FTSs serve as a means to gather potential evidence of intoxication. If a person refuses to comply with these tests, law enforcement officers can still proceed with an arrest based on their belief that the individual is intoxicated. Subsequently, they may conduct additional testing, such as a breathalyzer or blood test, to determine the individual’s level of impairment.
Remember that even if a person successfully passes the field sobriety tests, law enforcement officers can still make an arrest. However, they must have reasonable suspicion that the individual is under the influence of alcohol or drugs. The field sobriety tests are just one component of the overall assessment used by officers to determine impairment.
Field sobriety tests are commonly used by law enforcement as a tool. It is how they assess impairment and gather evidence in cases of suspected DUI or DWI.
However, it is important to recognize their limitations and the potential for inaccuracies. These tests are not infallible and can be influenced by various factors.
- Physical conditions
- Environmental conditions
- Subjective interpretation
If you find yourself facing DUI charges based on field sobriety tests, it is crucial to seek legal representation promptly. Consulting with a skilled attorney can make a significant difference in the outcome of your case. They work diligently to protect your rights, challenge the validity of the tests, and explore every avenue to fight the charges against you.
Remember, the results of these tests are not definitive proof of impairment. With the guidance of a knowledgeable attorney, you can fight for a fair resolution in your case.