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The Role of Field Sobriety Tests in DUI Cases

7 min read
Philip Ahn, Attorney

by Philip Ahn, Attorney

Field sobriety tests are critical in DUI cases as they evaluate a suspect’s performance during roadside stops. Conducted by law enforcement agencies, standard field sobriety tests may be critical evidence that influence the decision to file DUI charges by the arresting officer.

When a driver’s poor performance is observed in these tests, it can establish probable cause for further investigation. However, a competent attorney can argue that the evidence provided is not be sufficient to prove guilt beyond a reasonable doubt in court.

Challenging False Impairment Allegations: Addressing Field Sobriety Test Results

Environmental factors such as uneven terrain, poor lighting, or adverse weather conditions may cause misinterpretations of test results, causing an officer to falsely suspect impairment.

When conducted under challenging field conditions, a sober driver may inadvertently fail.

Furthermore, the subjective judgment of the administering officer may introduce bias and affect the interpretation of FST outcomes.

Such inaccuracies can raise concerns about the reliability of sobriety tests as indicators of drunk driving.

A DUI attorney can scrutinize the administration and interpretation of field sobriety tests and challenge their validity if necessary, advocating for their client’s rights during legal proceedings.

Countering false impairment allegations and addressing field sobriety test results is critical to defending against DUI charges. A defense attorney will meticulously examine the circumstances surrounding the field sobriety tests to identify potential inaccuracies or inconsistencies in their administration.

By meticulously scrutinizing the outcomes, the defense can cast doubt on the validity of the allegations and question the reliability of the tests as indicators of impairment. This comprehensive approach challenges the prosecution’s case and highlights any discrepancies that may weaken their argument.

Successfully contesting false impairment allegations can provide a more favorable outcome for the defendant, leading to the following:

  • The dismissal of charges
  • A reduction in the severity of penalties

Physical Or Mental Disqualifiers of Sobriety Tests

Physical or mental impairments or conditions can significantly impact the results of field sobriety tests, making it essential to consider these factors during the legal process, especially in DUI charges. Medical conditions, such as mild brain damage or certain physical limitations, can affect a person’s ability to perform the three standard sobriety tests, including the divided attention test.

These conditions may lead to false positives on the field sobriety test, inaccurately suggesting impairment even when the individual is sober. In DUI defense, assessing and presenting evidence of such impairments or medical conditions becomes crucial to accurately represent the individual’s abilities during the sobriety tests and ensure a fair legal proceeding.

Different Types Of Field Sobriety Tests

Different types of field sobriety tests play a crucial role in assessing a person’s potential impairment during a DUI stop.

Upon suspecting a driver operating under the influence, a law enforcement officer may administer field sobriety tests to evaluate the individual’s physical and cognitive abilities. These tests establish an individual’s coordination and balance:

  • The walk-and-turn test
  • The one-leg stand test

The horizontal gaze nystagmus test, also known as the HGN Test, is used to assess nystagmus (involuntary eye movements) when a person gazes to the side

These tests help establish probable cause for additional examination, such as a breathalyzer device or blood test to determine the driver’s blood alcohol concentration (BAC).

Understanding The Horizontal Gaze Nystagmus (HGN) Test

The Horizontal Gaze Nystagmus (HGN) Test is crucial in assessing potential intoxication during roadside stops. The HGN test involves a visual demonstration where a police officer observes the suspect’s eyes for involuntary jerking as they follow a stimulus, such as a pen or a flashlight, horizontally. This standardized manner of conducting the test helps officers determine possible impairment.

The results of the HGN test and other field sobriety tests can contribute to establishing probable cause for DUI charges by the arresting officer. Familiarity with the horizontal gaze nystagmus test and its proper administration ensures accurate evaluations during roadside stops and supports practical law enforcement efforts to ensure road safety.

DUI Walk And Turn Straight Line Test: Heel-To-Toe Steps For DUI Arrest

In the context of DUI arrests, the DUI walk, and turn test is a commonly used field sobriety test employed by police officers to assess a suspect’s level of impairment. During this two-party test, the individual is instructed to take nine steps in a straight line while placing one foot directly in front of the other, heel to toe, known as the heel-to-toe steps. Then the subject must walk in a straight line, heel to toe, while maintaining balance on one foot, during a return along the same path.

This balance test aims to evaluate the person’s ability to maintain proper coordination and balance while performing the prescribed actions. The DUI walk and turn test is one of several standardized field sobriety tests used to gather evidence when assessing potential driving under the influence cases.

Involuntary jerking of the body during the test may indicate possible impairment. These field sobriety tests play a significant role in the legal process, providing valuable evidence to aid officers in their assessments and potential decisions regarding further testing or arrest.

It is essential to understand that performance on these tests alone does not determine guilt. Still, they serve as critical tools to assist officers in evaluating whether further examination is warranted.

Performing The One Leg Stand Test

Performing the one-leg stand test is one of the field sobriety tests used by police officers to assess a suspect’s sobriety during a DUI investigation. In this test, the individual is instructed to stand on one foot while raising the other approximately six inches off the ground.

They must maintain balance while counting aloud for a specified duration, often around 30 seconds. The one-leg stand test evaluates the suspect’s ability to:

  • Follow instructions
  • Maintain balance
  • Divide their attention between physical and cognitive tasks

Throughout the test, the police officer observes signs of impairment, such as:

  • Swaying
  • Hopping
  • Using arms for balance
  • Putting the foot down before the instructed time elapses

Combined with other field sobriety tests, these indicators can establish probable cause for a DUI arrest, as they suggest potential alcohol or drug intoxication.

Chemical Tests: The Cornerstone Of DUI Investigations

Chemical tests are the cornerstone of DUI investigations, serving as vital tools to evaluate impairment and determine a driver’s blood alcohol concentration (BAC) or blood alcohol content. Among these tests, the blood test stands out as one of the most reliable methods for accurately measuring BAC.

When a driver performs poorly in field sobriety tests or shows signs of high blood alcohol concentration, a blood test is often conducted for additional analysis. A DUI case relies on these chemical tests as crucial evidence in determining whether an individual was driving under the influence, reinforcing the importance of accurate BAC assessments in legal proceedings.

Seeking Assistance From A DUI Defense Attorney

In a DUI case, seeking assistance from a defense attorney is crucial. A defense lawyer can:

  • Provide you with a free consultation to understand the specifics of your situation
  • Thoroughly analyze the evidence, including field sobriety test results
  • Build a strong defense strategy

By leveraging their knowledge and experience in handling DUI cases, a DUI defense lawyer can:

  • Advocate for your rights
  • Challenge the validity of the tests conducted

Their expertise can make a significant difference in the outcome of your case, potentially leading to:

  • Reduced charges
  • Or even a dismissal of the issue altogether

Can a DUI Attorney Contest Field Sobriety Test Administration In Court?

A DUI defense attorney can contest the administration of field sobriety tests in court. They have the expertise to scrutinize how these tests were conducted and challenge their validity as evidence of intoxication. During a DUI defense, an attorney may point out any errors or inconsistencies in the test procedures that could cast doubt on the results.

The defense attorney aims to weaken the prosecution’s case and protect their client’s rights by raising reasonable doubt about the accuracy and reliability of the field sobriety tests. If you are facing DUI charges, you must consult a defense attorney who can provide a free consultation and effectively challenge the field sobriety test results on your behalf.

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