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

    Playlist: "Field Sobriety Tests" in Nevada DUI Law

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

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

    Here are four key takeaways to know about field sobriety tests in Las Vegas DUI cases:

    1. Police use your FST scores to determine whether there is probable cause to arrest you for DUI.
    2. You are under no legal obligation to take FSTs.
    3. The federal agency NHTSA (National Highway Traffic Safety Administration) developed these FSTs.
    4. In practice, FSTs are not reliable indicators of alcohol impairment.

    In this article, our Las Vegas DUI attorneys discuss:

    1. Am I required to take field sobriety tests?

    No. 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

    Policeman watching DUI suspect performing one-legged-stand test

    The one-legged stand test requires suspects to keep one leg suspended while counting to 30.

    2. Are FSTs scientifically valid?

    No. 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-legged 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 the defendant:

    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 the suspect
      • disruptive visual and audial 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 the suspect

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

    Closeup of DUI suspect performing walk-and-turn test

    External factors such as wearing uncomfortable shoes can negate failing FST results.

    3. How can my attorney attack FSTs in court?

    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

    4. What FSTs are used in Nevada?

    Standardized Field Sobriety Tests (FSTs) are physical exercises that police ask DUI suspects to perform to determine whether they are under the influence of drugs or alcohol.

    Nevada’s standardized FSTs consist of three separate tests:

    1. Horizontal Gaze Nystagmus,
    2. Walk-and-Turn, and
    3. One-Legged Stand6
    DUI suspect performing walk-and-turn test at night

    When there is a suspected DUI, police ask the driver to perform 3 field sobriety tests including the “walk-and-turn.”

    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 an 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 the 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 the suspect’s pupils are at “maximum deviation.” If the 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 the suspect’s pupils jerk prior to the penlight being at a 45-degree angle away from the suspect’s face. If the 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 a suspect can show is six (which is three for each eye). Exhibiting four or more clues is a failing score.7

    Walk-and-Turn (WAT)

    The Walk and Turn test is a physical agility and coordination test. You are instructed to take nine (9) 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.
    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

    One-legged 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 you are impaired.9

    5. What happens before the FSTs?

    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.

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

    Police officer performing HGN test on DUI suspect

    The HGN test is only 77% reliable.

    6. What happens after the FSTs?

    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. How about non-standardized field sobriety tests?

    Some “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. These non-standardized FSTs are:

    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, your DUI defense attorney can seek to have them excluded from evidence for lack of scientific basis.

    Additional Resources

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

    Legal References:

    1. See, for example, Department of Motor Vehicles & Pub. Safety v. Evans (Nev. 1998) 952 P.2d 958 (the defendant refused to take two of the three FSTs).
    2. See, for example, Department of Motor Vehicles v. Torres (Nev. 1989) 779 P.2d 959 (the defendant was asleep behind the wheel).
    3. See, for example, Department of Motor Vehicles & Pub. Safety v. Becksted (Nev. 1991) 813 P.2d 995 (“No field sobriety test was administered for safety reasons.”).
    4. NHTSA Student Manual at VIII/3-14; see also Stuster & Burns, Validation of the Standardized Field Sobriety Test Battery at BACs Below .10 percent, U.S. Dept. of Transportation Rep. No. Dot-HS-808-839 (1998), at 33; Burns & Moskowitz, Psychophysical Tests for DWI Arrest, U.S. Dept. of Transportation Rep. No. DOT-HS-802-424 (1977); Anderson, Schweitz & Snyder, Field Evaluation of Behavioral Test Battery for DWI, U.S. Dept. of Transportation Rep. No. DOT-HS-806-475 (1983). The Southern California Research Institute (or “SCRI”) was commissioned by NHTSA to develop the FSTs in 1975, with a subsequent study done in 1981. Jack Stuster, Jack, and Marcelline Burns, Validation of the Standardized Field Sobriety Test Battery at BACs below 0.10 Percent, NHTSA (August 1, 1998).
    5. See, for example, Department of Motor Vehicles & Pub. Safety v. McLeod (Nev. 1990) 801 P.2d 1390 (field sobriety tests were invalidated because of defendant’s head injury).
    6. U.S. Department of Transportation “DWI Detection and Standardized Field Sobriety Testing” NHTSA Student Manual (October 2015).
    7. Wilkinson, Kime (1974) (oral dose of alcohol-impaired eye movement of all subjects); Lehti, The Effect of  Blood Alcohol Concentration on the Onset of Nystagmus, 136 BLUTALKOHOL 414 (West Germany 1976); NHTSA Student Manual (2006) at VIII/4. See, for example, Wright v. State DMV (2005) 121 Nev. 122; Rodriguez v. State (Court of Appeals, 2015) 131 Nev. 1339; Gordon v. State (2005) 121 Nev. 504; Holmes v. State (Nev. 2021) 498 P.3d 772; Cote v. State (Nev. 2019) 435 P.3d 668.
    8. NHTSA Student Manual at VIII/4.
    9. Id., at VIII/13, VIII/14, and VII/6.
    10. NRS 484C.150. Note that DUI suspects give “implied consent” to take a PBT. Suspects who refuse will have their license confiscated immediately and face a one (1) year-long license revocation. See also Weaver v. State (2005) 121 Nev. 494; Johnson v. State (1995) 111 Nev. 1210.
    11. NRS 484C.160. Note that DUI suspects give “implied consent” to take an evidentiary breath or blood test; Missouri v. McNeely (2013) 569 U.S. 141.
    12. NHTSA Student Manual at VIII/7.
    13. fieldsobrietytests.org.

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