Field Sobriety Tests

Police officers often use field sobriety tests to look for signs of intoxication. They receive specialized training to spot impaired drivers. If a law enforcement officer stops you on suspicion of driving under the influence (DUI), you may have questions about what to expect.

In this article, we’ll discuss what field sobriety tests are and the legal requirements associated with them. We’ll also explain your rights during a DUI stop and field sobriety test.

If you have questions related to field sobriety tests or you find yourself facing DUI charges, consult with a DUI attorney. Drunk driving charges can come with severe penalties, so it’s in your best interest to have an advocate on your side.

What Are Field Sobriety Tests?

Field sobriety tests (FSTs), sometimes called roadside sobriety tests, help police establish probable cause to make an arrest under DUI laws. They usually happen before chemical tests, such as a Breathalyzer test or other breath tests, or blood, saliva, and urine tests.

Officers will likely record your performance on field sobriety tests for evidence should you receive a DUI charge.

Observing Erratic Driving

In general, police officers will pull you over if they notice you’re showing any signs of driving under the influence, such as:

• Swerving
• Speeding
• Driving too slowly
• Failing to stop
• Failing to yield
• Any other indication that signals to the officer that you’re driving drunk

Suppose you have a good reason for driving erratically. In that case, the officer may let you go with only a ticket or a warning. However, officers will look to see if your eyes are blurred or bloodshot or if your breath smells like alcohol. If they suspect you’re impaired, they may proceed to ask you to step out of the vehicle and complete a field sobriety test.

Are Field Sobriety Tests Standardized?

While law enforcement may use various sobriety tests around the country, some types of tests follow the same procedures. The National Highway Traffic Safety Administration (NHTSA) endorses the Standardized Field Sobriety Test (SFST).

To ensure accuracy and admissibility in court, standardized tests are performed in the exact same manner every time. Police officers undergo extensive training in performing SFSTs for consistency.

Common Types of Field Sobriety Tests

A police officer typically performs three types of field sobriety tests during a traffic stop:

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

These tests allow an officer to observe your balance, physical ability, attention level, or other factors that the officer may use to determine whether you are driving under the influence of drugs or alcohol.

Horizontal Gaze Nystagmus (HGN)

The term “horizontal gaze nystagmus” refers to the involuntary jerking of the eye that occurs naturally when the eye gazes to the side. This jerking, or nystagmus, becomes exaggerated when you are under the influence of alcohol.

Officers look for three indicators of impairment in each eye:

• Inability to follow a moving object smoothly
• Distinct eye jerking when the eye is facing the farthest from center
• Eye jerking when the eye is 45 degrees off-center

Officers conduct the HGN test by having a driver try to track an object with their eyes, such as a pen, a flashlight, or the officer’s finger.

Walk and Turn (WAT)

This test aims to gauge your ability to complete tasks with divided attention. Most unimpaired people efficiently do this task. The police officer will direct you to take a certain number of steps (usually nine) heel-to-toe, along a straight line. Then, you turn on one foot and return in the same manner in the opposite direction.

One-Leg Stand (OLS)

The officer asks you to stand with one foot about 6 inches off the ground and count for 30 seconds. Swaying while balancing, using arms to balance, hopping, or putting the foot down indicates possible impairment.

Accuracy and Limitations of Field Sobriety Tests

According to the NHTSA, the nystagmus test is around 77% accurate at detecting impairment when blood alcohol content (BAC) is above 0.10%. Meanwhile, the walk-and-turn test is around 68% accurate. The one-leg stand is around 65% accurate.

When used together, the three standardized field sobriety tests accurately indicate alcohol impairment in about 82% of cases.

People who fail FSTs are usually given a preliminary alcohol screening (PAS) to determine their blood alcohol concentration before an arrest. This may be a Breathalyzer or other breath tests.

Before performing FSTs during a traffic stop, the police officer should ask you about any medical conditions, disabilities, or injuries. These factors can affect the accuracy of the tests.

The officer will also consider your age, current medications, and other conditions in determining if FSTs are appropriate. For example, an inner ear condition or multiple sclerosis may make you unsteady, causing test failure. Conditions like weather, lighting, and the road surface can also impact the accuracy of a field sobriety test.

Non-Standardized Field Sobriety Tests

In addition to the standardized tests, an officer may also ask a driver to perform other tests during a DUI stop.

Non-standardized field sobriety tests may include:

• Standing with feet together and tipping the head backward
• Counting the number of fingers an officer raises
• Reciting the alphabet
• Counting backward
• Standing and leaning back to look up at the sky while holding arms to the side
• Closing your eyes and touching your nose with a finger

These tests are typically aimed at testing a person’s balance and focus.

It is important to know that field sobriety tests are subjective. Even sober individuals can fail this test due to age, physical condition, or injuries that can affect the person’s performance. There are chances to fail the field sobriety test regardless of sobriety.

Your Rights During Field Sobriety Tests

Understanding your rights during a DUI stop is crucial for protecting yourself legally. Several important considerations apply when law enforcement requests field sobriety tests.

Probable Cause vs. Reasonable Suspicion

Police officers do not need probable cause to conduct field sobriety tests. They only need reasonable suspicion that you may be driving under the influence. This is a lower standard than probable cause, which is necessary for making an arrest.

Officers might develop reasonable suspicion based on observing erratic driving, the smell of alcohol, slurred speech, or bloodshot eyes. The field sobriety tests assist officers in establishing the probable cause for an arrest.

Miranda Rights and Field Sobriety Tests

Police officers do not need to read you your Miranda rights before performing the standardized field sobriety tests. Miranda warnings are only required during “custodial interrogation.” This generally means situations where you are not free to leave the scene.

During the initial traffic stop and the field sobriety testing phase, you are typically not considered to be in custody. Thus, the Miranda rights do not apply. However, once you are formally arrested, officers must read you your Miranda rights before any custodial interrogation begins.

Some courts have also found that some non-standardized tests, like reciting the alphabet, are potentially self-incriminating testimony. In that case, you’d need to be read your rights.

Officers also cannot extend detention beyond the original traffic stop purpose. They must have a reasonable suspicion of additional criminal activity.

For instance, in Ohio, if an officer stops you for a different traffic violation (like running a stop sign), they cannot randomly perform a field sobriety test. They can only ask you to do a sobriety test if they have a reasonable suspicion that you are driving under the influence.

Right to Refuse Field Sobriety Tests

Field sobriety tests are generally voluntary in most states. What this means is that you can refuse to perform the sobriety test. This is a crucial distinction from chemical tests such as breathalyzers, blood, or urine tests. These tests typically fall under the mandatory implied consent laws. Essentially, these laws view the operation of a vehicle on public roads as implied consent to undergo testing if necessary.

However, despite a refusal to undergo a field sobriety test, officers can still arrest a person based on other observations. For instance, the person is driving erratically, they have slurred speech, or an alcohol odor is present.

After making the arrest, the officer can still require a driver to undergo chemical testing. So, it is important to remember that yes, you have the right to refuse a field sobriety test. But this will not prevent police from arresting you if they have sufficient evidence to believe that you are driving under the influence. Prosecutors may also be able to use your refusal as evidence of guilt if your case goes to trial, depending on state law.

Do Implied Consent Laws Apply to Field Sobriety Tests?

All states have enacted implied consent laws. Under an implied consent law, law enforcement deems you to consent to chemical tests when you drive a motor vehicle. Chemical tests are more invasive than field sobriety tests, as they may require collecting a blood, urine, or saliva sample.

While you may refuse to comply with chemical tests, you will face consequences for not cooperating. These vary by state but generally include immediate driver’s license suspension, fines, or even a criminal charge.

Field sobriety tests differ, as refusing them will not bring additional penalties. However, refusal of FSTs or chemical tests will not prevent your arrest or keep you out of a police station. An officer can still arrest you on a DUI charge if they reasonably suspect intoxication.

Speak with a Criminal Defense Lawyer

Field sobriety tests (FSTs) are among several different techniques used by police to check a person’s level of intoxication. If you have questions related to FSTs in relation to a DUI arrest, speak with a DUI lawyer. They can evaluate your case and provide you with valuable legal advice.

A criminal defense attorney can help protect your rights and find the best possible legal defense to your DUI case. Challenging the validity of a field sobriety test is a common defense. An experienced local attorney will know what to look for and how to challenge this evidence.