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How Field Sobriety Tests Influence a DUI Investigation

A law enforcement officer may motion you to pull over and request you to take a field sobriety test. If you allegedly 'fail' this test, you may be arrested for DUI. Most police officers in Los Angeles are fond of using field sobriety tests to find a probable cause of arresting you. However, these tests are unreliable; and most of them are administered incorrectly and subjectively.

We at the Jonathan Franklin DUI Attorney understand how law enforcement officers carry out these tests in Beverly Hills and the Los Angeles area. With our help, you can build an excellent defense strategy to show the court that your alleged 'poor performance' on these tests does not mean that you were impaired.

We will help you challenge the field sobriety test results, regardless of the type of DUI charge you are facing. Ultimately, the court will be convinced that the results were invalid; and your case will be dismissed, or your charges will be reduced. Read on to know more about how field sobriety tests influence a DUI investigation.

What is the Main Purpose of a Field Sobriety Test?

You may wonder why a law enforcement officer would conduct a field sobriety test. The main purpose of a field sobriety test is to gather evidence to help the prosecution convict you of DUI. It is nearly impossible to pass a field sobriety test, especially if the investigating officer has set his/her mind to arrest you. Therefore, field sobriety tests are purely ceremonial; and you may still be arrested for DUI even if you 'pass' them.

Field sobriety tests evaluate an individual’s mental acuity and coordination. Law enforcement officers use them to assess whether your performance indicates that you are under the influence of drugs or alcohol.

Police officers also use these tests to determine whether you can follow instructions. A law enforcement officer will issue you a set of instructions and observe if you fail to implement any of them. If you don't follow the instructions, you will be considered to have 'failed' the test.

The officer will record your performance on these tests. The prosecutor will utilize these performance records to testify during the trial that you were intoxicated.

When Police Officers Can Request Field Sobriety Tests

A law enforcement officer can only motion you to pull over if he/she has a probable cause. For instance, the police officer may notice you driving recklessly or violating a traffic law.

When you stop, the law enforcement officer may suspect you of driving under the influence. The police officer’s suspicion may be raised if:

  • You emit an alcoholic/marijuana odor
  • You have a container of alcohol inside your vehicle
  • You have slurred speech, red face, or bloodshot eyes
  • You give incoherent or inappropriate responses to his/her questions
  • You responded in the affirmative when he/she asked you whether you had been drinking

Under the enlisted circumstances, the law enforcement officer will request you to take a field sobriety test.

Can I Refuse to Submit to Field Sobriety Tests? 

You will not face any criminal or civil penalties when you refuse to submit to a field sobriety test. You can decline the test politely and leave the police officer to do what he/she believes is best per his/her discretion.

You may believe that if you pass the test, you won't be arrested for DUI. As we asserted earlier, field sobriety tests are just ceremonial. In most instances, the police officer has already decided whether or not to arrest you before he/she subjects you to the test.

In a way, field sobriety tests are 'specifically designed for failure.' All they do is to provide another reason for the law enforcement officer to validate why he/she motioned you to pull over and gather more evidence against you. Generally, we recommend motorists to politely decline to take the tests upon the request of an officer.

However, individuals who are below 21 years old and are on probation for prior DUI may face additional penalties if they refuse to submit to the field sobriety tests. Persons who are on probation may have their terms revoked and serve jail time instead. Those who are less than 21 years old may lose their driver’s licenses.

How Field Conditions Affect Sobriety Test Results

Several field conditions can affect sobriety test results. These conditions may make it extremely difficult for DUI suspects to implement the officer’s instructions.

California law enforcement officers have an obligation to ensure that the testing is carried out in suitable conditions. However, most of them do not do so.

According to the National Highway Traffic Safety Authority (NHTSA), field sobriety tests must be performed under appropriate and safe conditions. NHTSA lists the three standardized tests that law enforcement officers can use to assess whether an individual is under the influence. Besides the standardized tests, police officers can also use non-standardized tests to evaluate if a person is impaired, but they must also be given under reasonable and fair conditions.

Conditions that may influence the validity of a field sobriety test include:

1.       Lighting Conditions

The tests should be conducted in a well-lit environment to enable the suspects to see the ground and the police officer. If there is insufficient lighting, the law enforcement officer should utilize a flashlight. Even sober individuals may be unable to complete the field sobriety tests in a totally dark environment.

2.       Surface Conditions

Some surface conditions can increase the risk of a suspect to slip or fall. Field sobriety tests should be conducted on surfaces that are reasonably non-slippery, dry, level, and hard. Also, there should be sufficient space to allow the suspect to perform the test. If the law enforcement officer is unable to follow these guidelines at the DUI checkpoint, he/she should move the suspect to a convenient location.

3.       Auditory Conditions

The suspect should hear clearly the officer’s instructions as he/she takes the field sobriety test. Sirens, disruptive honking, and other forms of noise disturbances may affect how the suspect perceives the officer’s instructions.

Standardized Field Sobriety Tests

The NHTSA has issued various police protocols for use in DUI field sobriety testing. This federal agency has standardized three tests, amongst a dozen others, which law enforcement can use to evaluate whether an individual is under the influence. The standardized tests include:

  • The horizontal gaze nystagmus test
  • The one-leg stand test
  • The walk and turn test

According to the NHTSA, these tests reliably predict whether an individual is impaired, provided that they are administered correctly. The NHTSA validated these tests in 2018, after analyzing a series of field sobriety tests that the San Diego Police Department conducted. The agency noted that there was a high correlation between DUI impairment and poor performance on standardized tests.

As you can see, field sobriety tests have the support and backing of both federal and local governmental agencies. Law enforcement officers must conduct them per their established or published protocols, or they will not be considered as valid.

The court will permit the investigation officers to testify how you performed on these tests. Typically, poor performance is linked to a high blood-alcohol concentration. Your performance on the field sobriety test may strengthen the evidence of the prosecution, and this is why we advise you to politely decline to take the test when a police officer requests you to do so. Let's take a closer look at the three standardized field sobriety tests as set out by the NHTSA.

1.       The Horizontal Gaze Nystagmus Test

The horizontal gaze nystagmus test is the most commonly used field sobriety test in Los Angeles. This is because it is considered to be more reliable, and it can easily strengthen the prosecutor’s case provided he/she builds a solid foundation.

During this test, the police officer will hold a penlight, pencil, or any other object in front of your eyes. Then, the officer will ask you to track it, as he/she constantly moves it from one side to another.

In this test, the officer will look for the angle at which your pupil will begin to jerk involuntarily. If the angle is or below 45 degrees, he/she will assume that your BAC is 0.10% or higher. The horizontal gaze nystagmus test assumes that how soon your eyes start to jerk indicates the level of your blood-alcohol content.

2.       The Walk and Turn Test

The law enforcement officer will ask you to take nine steps. These steps should be taken as you walk heel-to-toe, and in a straight line. After you have completed the nine steps, the police officer will instruct you to pivot on one foot. Then, you will be required to walk back to where you started from in the same way. The law enforcement officer who is issuing the test should first demonstrate how you should complete the test before asking you to do so.

During the walk and turn test, the police officer will utilize eight indicators to evaluate if you are impaired. These indicators include:

  • You did not maintain your balance when you were listening to the instructions of the officer
  • You began walking even before the police officer finished issuing the instructions
  • You took less or more than nine steps
  • You stopped during the test to stabilize yourself
  • You lost balance and almost fell while turning
  • You did not touch your heels when walking
  • You utilized your arms to support yourself
  • You did not walk in a straight line

If you exhibit two or more of these indicators, the law enforcement officer will believe that you are under the influence. The walk and turn test evaluate your concentration capacities, and it is primarily designed for the officer to know whether you can listen to and execute instructions simultaneously. This test evaluates both your physical and mental capabilities.

3.       The One Leg Stand Test

Here, the officer will request you to stand on one foot; and lift the other foot six inches off the ground. Then, you will have to count in thousands, until you reach one thousand and thirty, or when the officer instructs you to stop. As you stand, you should focus on the raised foot, and your arms and hands should rest by your sides.

Just like the walk and turn test, the law enforcement officer should demonstrate how to perform this test. Also, the officer will observe whether you can follow instructions and execute them simultaneously while maintaining your balance. He/she will look for four possible clues that indicate impairment. These clues include swaying back and forth or from side to side, using your arms to maintain balance, hopping, and being unable to keep your foot above the ground.

Non-Standardized Field Sobriety Tests

California law enforcement officers may still use non-standardized field sobriety tests to assess whether you are impaired, even though the NHTSA has not validated them. These non-standardized tests include the hand pat test, the Rhomberg balance test, the finger-to-nose test, and the finger count test.

These tests have not been validated by the NHTSA because there is no or little correlation between DUI impairment and their performance. Moreover, they have no established protocols; and their procedural administration varies from one officer to another.

The Accuracy of Field Sobriety Tests

As per the NHTSA, the three standardized tests are highly accurate; and law enforcement officers are justified to make arrest decisions after they have gauged your performance. However, the NHTSA illustrates that the court should only consider the test results accurate if they were carried out in the standardized, prescribed manner. If the police did not follow the established protocol, the defendant could challenge the validity of the test results.

Despite the NHTSA’s assertions, we believe that field sobriety tests may not be accurate, even if they were administered correctly. In most of our DUI cases, we have found out that the standardized tests indicated false positives. We can challenge the results of the test in various ways, per the facts and circumstances of your arrest.

Find a Los Angeles DUI Attorney Near Me

Whether or not you took a field sobriety test, we at Jonathan Franklin DUI Attorney can assist you in winning your case. Call us today at 323-464-6700 if you are in Beverly Hills or the Los Angeles area to discuss with an attorney the best possible DUI defenses for your situation.

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Jonathan Franklin DUI Attorney
6777 Hollywood Blvd Ste 508
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