Filed Sobriety Tests & Nevada DUI – Do I have to take them?

If you get stopped for DUI in Nevada, police will likely ask you to perform these three standardized field sobriety tests (FSTs) to gauge whether you may be under the influence of alcohol or drugs:

1. Horizontal gaze nystagmus test (the penlight eye test),
2. Walk and turn test, and
3. One leg stand test.

Police use your FST scores to determine whether there is probable cause to arrest you for DUI. However, you are under no legal obligation to take FSTs.

The federal agency NHTSA (National Highway Traffic Safety Administration) developed these FSTs. In practice, though, FSTs are not reliable indicators of alcohol impairment, and our legal team has extensive experience contesting failing FST scores.

In this article, our Las Vegas DUI attorneys will address the following key topics regarding field sobriety tests in Nevada:

• 1. Your Obligations
• 2. FST Accuracy
• 3. Fighting FST Results
• 4. The Three FSTs
• 5. What Happens Before
• 6. What Happens After
• 7. Non-Standardized FSTs
• Frequently Asked Questions
• Additional Reading

1. Your Obligations

FSTs are not mandatory in Nevada, even though the police may claim they are.¹

Therefore, you can politely decline to take the FSTs. That way, the state has less evidence to prove its case against you.

However, declining the FSTs likely ensures that the police officer will arrest you. Police construe FST refusals as a consciousness of guilt.

Note that officers should not administer FSTs on DUI suspects who are clearly too incapacitated or injured to comply.² Officers also should not administer FSTs if there is no safe and appropriate space to perform them.³

2. FST Accuracy

One out of four people who fail FSTs is not under the influence of drugs or alcohol. Therefore, the tests’ accuracy rates are very low:⁴

Standardized Field Sobriety Test	Reliability Rate for Determining DUI
Horizontal Gaze Nystagmus	77%
Walk and Turn	68%
One Leg Stand	65%

Through NHTSA, the US Department of Transportation outlines specific instructions about how to administer the tests and what “clues” police should look for to detect intoxication. The D.A. then uses failing FST results in court to try to prove that you:

• were impaired by alcohol or drugs or
• had an illegal blood alcohol content (BAC) of .08% or higher.

However, many non-DUI circumstances can cause false positives because of:

• Poor testing conditions
  • road and sidewalk surfaces that are uneven, soft, wet, or slippery
  • windy or rainy weather
  • unsuitable footwear, or lack of footwear
  • poor lighting for the officer to observe you
  • disruptive visual and auditory distractions such as traffic, bright lights, sirens, honking, and spectators
• Adverse physical or medical conditions
  • fatigue
  • anxiety
  • inner ear problems
  • mental disabilities
  • prescribed medication that may hinder coordination or cause nystagmus
  • physical limitations such as old age, injury, illness, or obesity
  • tight or uncomfortable clothing
  • back or leg problems
• Officer misconduct
  • intimidation
  • incorrect, inaudible, or misleading instructions and directions
  • distracting movements or statements
  • bias against you

In sum, several factors can cause a sober person to exhibit false clues during FSTs in Nevada.⁵

3. Fighting FST Results

Having represented hundreds of clients accused of drunk driving in Nevada, we rely on these four defenses to invalidate FST results:

1. FSTs are unreliable.
2. The setting was improper.
3. You had a physical condition that caused a false positive.
4. The police made mistakes.

Note that the Nevada Highway Patrol (NHP) typically has video equipment to record suspects performing FSTs, whereas local police departments like the Las Vegas Metropolitan Police Department (LVMPD) does not. Whether there are recordings of your FSTs will greatly influence how we fight your DUI case.

4. The Three Tests

Nevada’s standardized FSTs consist of three separate tests:

1. Horizontal Gaze Nystagmus,
2. Walk-and-Turn, and
3. One Leg Stand⁶

1) Horizontal Gaze Nystagmus (HGN)

Also called the pen test, the Horizontal Gaze Nystagmus test is an eye test in which you are instructed to keep your eyes fixed on the officer’s penlight (or another object) as the officer moves it from side to side. In the meantime, the officer observes your pupils for involuntary jerking (called “nystagmus”), which can indicate impairment.

Specifically, the police officer is checking for three “clues” of intoxication in each eye:

1. Lack of smooth pursuit. This is where your pupil spontaneously jerks while following the police officer’s penlight. Theoretically, a sober person’s eyes would move smoothly.
2. Distinct nystagmus at maximum deviation. For four seconds, the officer holds the penlight very far to the side so your pupils are at “maximum deviation.” If your pupils bounce (“jerking of the eyes”), it may be a sign of a high BAC level.
3. Onset prior to 45 degrees. As the officer moves the penlight back and forth, the officer is studying whether your pupils jerk prior to the penlight being at a 45-degree angle away from your face. If your pupils do jerk, it could be a sign of intoxication.

During the HGN test, the officer is tallying how many “clues” each eye is exhibiting. The maximum number of clues you can show is six (which is three for each eye). Exhibiting four or more clues is a failing score.

Note that being under the influence is merely one cause of nystagmus. There are at least 35 other causes – including drowsiness – that can trigger nystagmus. Therefore if you fail the HGN, we would try to argue that your nystagmus was due to one of these non-impairment reasons.

There is also evidence that police incorrectly administer HGNs up to 95% of the time, such as by doing an incorrect number of passes. We can use this statistic to suggest that failing test results are due to officer error.⁷

2) Walk-and-Turn (WAT)

The Walk and Turn test is a physical agility and coordination test. You are instructed to take nine steps heel-to-toe back and forth in a straight line.

In addition, you have to keep one foot on the ground as you pivot around during the halfway point. Finally, you have to count the numbers aloud.

In the meantime, the police officer is looking for eight “clues” of intoxication:

1. Losing balance while the police officer is giving instructions. (This means that police are studying you during the “instruction phase” of the test before the “walking phase” even begins.)
2. Starting to walk before the police officer finishes giving the instructions.
3. Pausing during the walk. (Walking slowly is okay as long as there is no stopping.)
4. Not walking heel-to-toe.
5. Stepping out of line.
6. Using arms to balance.
7. Losing balance while doing the turn.
8. Taking an incorrect number of steps.

Showing two or more clues during the WAT test is considered a failing score.⁸

3) One Leg Stand (OLS)

For the One Leg Stand test, Nevada police have you stand in place on one leg while keeping the other leg extended forward about six inches off the ground. Simultaneously, you have to count aloud to 30 by reciting “one one-thousand, two one-thousand, three one-thousand…” etc.

Like the WAT, the OLS is considered a divided attention test because your mind has to multitask between physical exercise and counting aloud.

Meanwhile, the police officer is looking out for the following four “clues” of intoxication:

1. Hopping.
2. Putting the raised foot down.
3. Using arms for balance.
4. Swaying.

Exhibiting two or more clues in the OLS test is deemed a failing score. Incorrectly counting the numbers does not negatively impact the score, though the officer will take it as further probable cause that you are impaired.

Note that the NHTSA manual mentions the “2-Inch Heel Rule,” whereby suspects in two-inch-plus heeled shoes should be offered the opportunity to take them off for the OLS. If you fail the OLS while wearing heels, we would argue that the results are due to your footwear and not impairment.

The NHTSA manual also mentions the “50 Pound Rule,” which is an acknowledgment that suspects who are overweight by at least 50 pounds may experience difficulty performing the OLS even while sober. Therefore if you are overweight and fail the OLS, we would argue that the results do not constitute probable cause of impairment.⁹

5. What Happens Before

After a law enforcement officer pulls you over for a traffic stop on suspicion of DUI, the officer will first ask some cognition-testing questions, such as requesting that you take out your driver’s license and registration.

In the meantime, the officer will be observing whether:

• your speech is slurred,
• your eyes are glassy or bloodshot, and
• you smell of alcohol or marijuana.

If you are manifesting signs of intoxication, the police officer will then ask you to exit the vehicle and perform the FSTs.

6. What Happens After

If you do not pass the FSTs, the police officer will then ask you to submit to a preliminary breath test (PBT) to see if the results are .08% or higher (which is above the legal limit). Then, depending on the results and surrounding circumstances, the officers may decide they have probable cause for a DUI arrest.¹⁰

If you do pass the field sobriety tests, you are usually released at the scene. Depending on the reason you were pulled over, the officer may issue you a traffic citation, such as speeding.

Note that whether you get arrested for DUI is up to the police officer’s discretion. In some cases, the police may decide there is probable cause to believe you are under the influence even if you pass the FSTs and PBT.

Evidentiary Tests

Following a DUI arrest, Nevada law requires you to submit to an evidentiary DUI breath test or a DUI blood test. (If the officer suspects DUI of controlled substances, you have to take the blood test since breathalyzer tests do not register narcotics levels.)¹¹

If you refuse to submit to a chemical test of breath or blood, the police can physically constrain you to get a blood sample by force. The police just need to get a warrant first so that the blood test results will be admissible in court.¹²

7. Non-Standardized Field Sobriety Tests

Dozens of “non-standardized” field sobriety tests exist, but Nevada police rarely use them. This is because no national, reliable studies exist that demonstrate any correlation between the test results and the driver’s impairment. Some of the non-standardized FSTs are described in this table:

Non-Standardized FSTs	Instructions
Rhomberg stationary balance test	You stand upright with feet together while leaning your head back and holding out your arms to the side.
Finger-to-nose test	You close your eyes, reach out your dominant arm, and then try to touch your nose with your index finger. This is a routine test in neurology exams.
Finger count test	The officer raises their hand, and you count the number of fingers the officer is displaying. This test is meant to detect whether your vision is blurry.13

If a Nevada police officer does administer these non-standardized FSTs, we would seek to have them excluded from evidence for lack of scientific basis.

Frequently Asked Questions

Do I have to take field sobriety tests if police ask me to in Nevada?

No, field sobriety tests are not mandatory in Nevada. You can politely decline to take them, even though police may claim they are required. However, refusing the tests will likely result in your arrest, as officers view refusal as a sign of guilt.

How accurate are field sobriety tests at detecting drunk driving?

Field sobriety tests have low accuracy rates. One out of four people who fail these tests is actually sober. The horizontal gaze nystagmus test is 77% accurate, the walk-and-turn test is 68% accurate, and the one-leg stand test is only 65% accurate.

What happens if I fail the field sobriety tests?

If you fail the field sobriety tests, the police officer will likely ask you to take a preliminary breath test to check your blood alcohol level. Based on these results and other factors, the officer may decide there is probable cause to arrest you for DUI.

Can medical conditions or other factors affect my field sobriety test results?

Yes, many non-DUI factors can cause you to fail field sobriety tests even when sober. These include medical conditions like inner ear problems, fatigue, anxiety, physical injuries, poor weather conditions, uneven surfaces, uncomfortable shoes, and even being overweight by 50+ pounds.

Additional Reading

For more in-depth information on field sobriety tests, refer to the following:

• National Highway Traffic Safety Administration (NHTSA) manual on standardized field sobriety tests – Detailed information about how police test suspected drunk/drugged drivers
• Evaluation of Field Sobriety Tests for Identifying Drivers Under the Influence of Cannabis: A Randomized Clinical Trial – A JAMA Psychiatry article about how many sober drivers fail FSTs
• Field Sobriety Tests and THC Levels Unreliable Indicators of Marijuana Intoxication – National Institute of Justice article on the unreliability of FSTs
• Gaze‐evoked nystagmus induced by alcohol intoxication – A J Physiol. article on how alcohol affects eye movements
• The Drug Evaluation and Classification (DEC) Program – A course for members of the National District Attorneys Association about how drug recognition experts (DREs) work

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