Category Archives: Field Sobriety Tests
Law enforcement officers rely heavily on field sobriety tests (FSTs) in California to determine if a driver is impaired by alcohol or drugs during a traffic stop. The FSTs may be the only “evidence” an officer collects during a DUI investigation to justify an arrest for driving under the influence. The theory is that poor performance on field sobriety tests indicates alcohol or drug impairment.
However, these “standardized” field sobriety tests are not perfect. Even if the conditions are ideal and the police officer administers the FSTs precisely as directed by the NHTSA guidelines, the results of field sobriety tests can be inaccurate. According to the Instructor Guide provided by the National Highway Traffic Safety Administration, the accuracy levels for the FSTs are:
- Walk and Turn Test – 79% accurate
- One Leg Stand Test – 83% accurate
- Horizontal Gaze Nystagmus Test – 88% accurate
California drivers need to understand their rights regarding field sobriety tests. For example, a California driver does not have to take the field sobriety tests when stopped for suspicion of drunk driving.
California Drivers Can Refuse to Take Field Sobriety Tests
If you are pulled over for drunk driving, the police officer will ask you to take the field sobriety tests. He is looking for signs of impairment based on your performance on the FSTs. California does not impose any penalty for refusing to take field sobriety tests during a traffic stop.
As experienced DUI defense lawyers, we generally recommend that California drivers respectfully decline to take field sobriety tests for several reasons. Primarily, a sober person can fail a field sobriety test for reasons that have nothing to do with alcohol or drugs in their system.
Unlike chemical tests (i.e., urine, blood, or breath test) that determine your blood alcohol content (BAC), the field sobriety test the officer gives you is a subjective review of “signs” that could indicate you are a drunk driver. The officer may have already made up his mind about arresting you for drunk driving. Taking the FSTs gives the police officer additional “evidence” to present to the court that justifies the DUI charges.
Failing field sobriety tests could result in one or more charges under the California Vehicle Code, including driving under the influence and DUID (driving under the influence of drugs).
To help you understand how California field sobriety tests work and how the results can be incorrect, we discuss the standardized FSTs and some non-standard field sobriety tests used by California police officers during a DUI stop.
DUI Field Sobriety Tests Used in California
As discussed above, the NHTSA has approved three field sobriety tests to be used by police officers during a roadside DUI investigation. The NHTSA considers these tests to be good indicators of a person’s impairment.
The NHTSA bases its “validation” of these tests in part on a study by the Sand Diego Police Department. The study reported a strong connection between poor performance on these tests and alcohol or drug impairment. The tests are collectively referred to as the “standardized FSTs.”
The Walk and Turn Test (WAT Test)
This divided attention test requires a person to simultaneously concentrate on a physical and mental task. For the test to be accurate, the police officer must give the person exact instructions for completing the test. The person must remember the instructions and complete them in order correctly.
Generally, the police officer tells the person to take nine heel-to-toe steps in a straight line (either a line on the road or an imaginary line). After completing nine heel-to-toe steps, turn around and take nine heel-to-toe steps back to the beginning point.
There are eight signs that the police officer may notate that could indicate the person is intoxicated or under the influence of drugs:
- Starts walking too soon
- Cannot maintain balance during the instructions
- Fails to walk in a heel to toe fashion
- Uses the arms to balance
- Takes the wrong number of steps
- Stops while walking
- Steps off the line
- Fails to make the turn correctly
This FST has a 79% accuracy rating for indicating a BAC of .08 or greater because of poor performance. There could be many reasons why a person is unable to maintain balance while walking heel to toe.
The Horizontal Gaze Nystagmus Test (HGN Test)
Nystagmus is the involuntary movement or “jerking” of the eyes from side to side, up and down, or in a circle. Horizontal nystagmus describes the uncontrollable and rapid movement of the eyes from side to side.
The HGN test given during a roadside field sobriety test involves the police officer noting the angel of the eye when it begins to “jerk” (exhibit nystagmus) as it moves side to side. The officer performs the test by moving a stimulus, such as a pen, from left to right and instructing the person to follow the object with their eyes.
Nystagmus at or before the 45-degree angle of the eye movement is associated with a high level of alcohol in the person’s system. However, the accuracy level of the HGN test is roughly 88%, according to the NHTSA. Therefore, the results of this field sobriety tests could be incorrect in at least 12% of the cases.
The One Leg Stand Test (OST Test)
This field sobriety test is another divided attention test used during a DUI traffic stop. While this test has a better accuracy rating according to the NHTSA, it still leaves a lot of room for errors.
During the OLT test, the police officer instructs the person to lift their foot about six inches off the ground. While holding that position, count from 1001 to 1030 and then look down at their foot.
Signs of impairment that the officer looks for during the test include swaying, hopping, using the arms to balance, and putting the foot down before completing the test.
Non-Standard DUI Field Sobriety Tests Used by Police Offices
In addition to the “standardized” field sobriety tests, police officers use various non-standard field sobriety tests during a DUI stop. The NHTSA has not approved or validated these tests because there is little to no evidence that poor performance on these tests indicates DUI impairment. Furthermore, the way the tests are administered can vary significantly from one law enforcement officer to another, increasing the chance that the test results are inaccurate.
Several “signs” the officer looks for when performing these non-standard FSTs include:
- Ability to follow instructions, including counting correctly, starting and stopping correctly, and remembering instructions
- Ability to balance and stand still
- Muscle tone and body/eye tremors
- Depth perception
- Uttering unusual phrases or sounds
- Lack of muscle control
- Ability to perform mental and physical tasks simultaneously
Some of the non-standard field sobriety tests used by California police officers include:
Finger Count Test
The police officer instructs the person to extend their hand with the palm facing upward in front of their body. Then, touch the top of the thumb to each finger, beginning with the index finger and working their way over to the little finger. While touching each finger, the person should count from one to four aloud. Then, the process is reversed for a total of three sets.
Finger to Nose Test
This non-standard FST is one of the most common field sobriety tests officers perform. First, a police officer instructs the person to stand with their feet together and their arms at their sides. Then, after making a fist with each hand and keeping the index finger extended, the person must tilt their head back and close their eyes.
The officer then instructs the person to extend either the left or right arm in front of their body and use their index finger to touch their nose. If the person cannot perform the test correctly, it is thought to be a sign of intoxication because the person lacks muscle control and coordination.
Romberg Balance Test
A police officer instructs the person to stand with their feet together, and their head tilted slightly backward. Then, with their eyes closed, the person must estimate when 30 seconds have passed. Finally, when they believe 30 seconds have passed, they will tilt their head forward, open their eyes, and say stop.
Hand Pat Test
The officer instructs the person to extend either the left or right hand in front of their body with the palm facing upward. Then, place their other hand on the top of that hand with the palm facing down.
Keeping the bottom hand in the same location, the person must use the top hand to “pat” the bottom hand while counting “one, two, one, two, etc.” In addition, the person must rotate their top hand on each of the counts so that they pat their bottom hand palm down on the “one” counts and palm up on the “two” counts.
What Can Affect the Accuracy of a DUI Field Sobriety Test?
Many things can affect the accuracy of DUI field sobriety tests. For example, there are several medical reasons why a person would exhibit signs of nystagmus, including multiple sclerosis, head injuries, certain medications, and cataracts.
Numerous physical and mental conditions may affect the accuracy of a test. Age, weight, inner ear problems, mental disabilities, anxiety, physical pain, and illness are just a few examples of why a person could “fail” a field sobriety test when they are not impaired by alcohol or drugs. In addition, being tired, having muscle fatigue from work or exercise, and stress can negatively impact a person’s ability to perform field sobriety tests correctly.
Weather and field conditions can have a significant impact on FST results. For example, if the test is given on an uneven surface, it increases the chance the person will lose their balance. In addition, bright lights from oncoming traffic and noise can affect test results.
The police officer’s conduct can result in inaccurate test results. For example, if the police officer does not provide clear instructions, the person may “fail” the test. Likewise, if the officer moves around, it can distract the person and result in inaccurate test results.
Even something as simple as wearing high heels, tight clothing, or baggy pants could adversely affect a person’s performance on field sobriety tests.
Fighting the Results of DUI Field Sobriety Tests in California
If you are arrested for DUI in California, you should discuss your legal options with a DUI defense attorney before pleading guilty to driving under the influence. There may be one or more grounds for challenging field sobriety tests.
When you are stopped for driving under the influence, an officer may have you perform one or more field sobriety tests. The purpose of these tests is to determine whether you are under the influence of drugs or alcohol. The National Highway Traffic Safety Administration (NHTSA) has approved and standardized three field sobriety tests for use during DUI investigations:
- HGN (horizontal gaze nystagmus) test
- Walk and turn test
- One-leg stand test
Many police officers use the “finger-to-nose” test during DUI investigations. However, this test is an unofficial field sobriety test that the NHTSA does not approve. As such, several issues can arise when a police officer uses the finger-to-nose test as part of a DUI investigation.
What is the Finger-to-Nose Test?
A police officer instructs you to close your eyes and slightly tilt your head backward. Then, with your index finger, you touch the tip of your nose. The police officer has you repeat the process three times with each hand. Before each attempt, the police officer informs you which hand to use to touch the tip of your nose.
During the finger-to-nose test, a police officer observes you for signs of impairment. Specifically, the officer observes:
- Your ability to follow instructions during the test
- The direction and amount your body sways during the test
- Whether you have body, leg, or eyelid tremors
- Your depth perception and muscle tone
- Unusual sounds or statements you make during the test
- Whether you can touch your nose with your index finger or other parts of your face
Because the finger-to-nose test is not a standardized field sobriety test, police officers are not required to use specific procedures to instruct the person how to perform the test. Likewise, officers are not required to perform the test under specific conditions.
Therefore, the test can produce wildly inaccurate results because of a police officer’s subjective view of the suspect’s performance. A DUI defense lawyer may attack the validity and results of the finger-to-nose test on many points.
Field Sobriety Tests Used During a DUI Investigation
The three NHTSA standardized three field sobriety tests used during DUI investigations. Several scientific studies validate the correlation between performance during these tests and DUI impairment through statistical means.
Police officers must follow strict and specific procedures for administering standardized field sobriety tests. Failing to follow the requirements for testing could make the results subject to challenge in court.
Even though the NHTSA only has three standardized DUI field sobriety tests, police officers often use several non-standard field sobriety tests during a DUI investigation. In addition to the finger-to-nose test, a police officer may use the following tests to judge your impairment level during a DUI investigation:
Hand Pat Test
You extend your hand out in front of your palm up and then place your other hand on top of that hand palm down, as if you are about to start clapping. Then, counting “one, two, one, two, etc.,” you pat your hands together. Your bottom hand remains stationary.
However, you turn the top hand from palm down to palm up between each movement. The result is that you “pat” your bottom hand with your top hand palm down on the “one” counts and palm up on the “two” counts.
Romberg Balance Test
During this test, you stand with your feet together and your head slightly tilted backward. Then, with your eyes closed, you must estimate when 30 seconds have passed. At that time, you tilt your head forward, open your eyes, and say stop.
Finger Count Test
The police officer instructs you to put one hand in front of you with your palm facing upward. You then touch your thumb to the tip of each finger, beginning with your index finger and ending with your little finger. As you touch each finger, you count from one to four. Then, the process is reversed and performed three times.
As with standardized field sobriety tests, police officers observe your ability to follow instructions, coordination, balance, body tremors, and comments made during these non-standardized field sobriety tests. The purpose is to determine if you are impaired by alcohol or drugs.
However, the results of these non-standardized field sobriety tests are also highly subjective. The same problems exist with these tests as with the finger-to-nose test.
Using the Finger-to-Nose Test to Examine the Cerebellum and Measure Ataxia
The instructions provided for the finger-to-nose test are designed to help measure ataxia. Ataxia is the lack of muscle control or coordination of voluntary movements. It may be caused by alcohol use.
The finger-to-nose test is supposed to detect a lack of voluntary coordination of voluntary muscle movements. A lack of coordination could indicate problems with the cerebellum, which could indicate intoxication.
Because the finger-to-nose test is not a standardized test, the instructions police officers give to suspects can vary. However, general instructions include:
- Stand with your feet together and your arms down at your side
- Make a fist with each hand, keeping the index finger extended and turn your hand so your palm faces upward
- Tilt your head back slightly
- Close your eyes (closing your eyes before tilting your head back could impair normal equilibrium)
- Extend your right (or left) arm straight out in front of your body and then touch your index finger to your nose before returning your arm back down to your side
As you perform the test, the police officer watches for “clues” or indicators of neurological dysfunctions that suggest you may have been driving under the influence of drugs or alcohol.
Specific “clues” the police officer notes include:
- Your inability to follow instructions, such as keeping your feet apart or extending the incorrect finger when making a fist.
- Being unable to stand still. You sway from side to side or back to front, so the police officer finds that your inability to maintain balance is a sign of impairment.
- You exhibit the “shakes” because you involuntarily tremble when performing the test. Your muscle tone may appear more rigid or limp than is expected for a sober person.
- You utter unusual sounds or make statements that the officer believes indicate you are intoxicated, such as signing while performing the test or repeatedly stating you have to “pee.”
- You take too much time or you try too fast to touch your finger to your nose. Either action could indicate a problem with depth perceptions.
- The officer notes whether you use the correct sequence for touching your nose that the officer gave you.
As stated above, the results of the finger-to-nose test are subjective. For example, an officer might believe that asking to use the bathroom is an unusual statement, while another officer might assume that you just need to urinate. Likewise, belching could be interpreted as being intoxicated, but it could result from having just eaten a large meal.
Therefore, the reliability of the finger-to-nose test can be questionable.
Challenging the Results of the Finger-to-Nose Test
Because the NHTSA has not approved the finger-to-nose test, police officers do not have a specific list of criteria to use when determining if a person “fails” the test. Furthermore, the procedure for administering the test can vary significantly from one jurisdiction to another and even more from one officer to another. Therefore, the validity of the test and the accuracy of the results are subject to scrutiny.
Additionally, there are numerous reasons why a person could fail the finger-to-nose test that have nothing to do with intoxication. Conditions or circumstances that could impact the results of the finger-to-nose test include, but are not limited to:
- Ataxia caused by medications instead of being caused by alcohol intoxication. Certain medications may cause a lack of coordination of muscle movements, such as anti-seizure medications and medications for depression.
- Brain damage and neurological defects could negatively impact the function of the cerebellum, which may impact coordination.
- Mental disabilities may prevent a person from understanding the instructions given by police officers when performing the finger-to-nose test.
- Roadside conditions could impact the results of the test. For example, load noises from traffic, flashing lists, and other distractions could be the cause of the “clues” of intoxication the officer notes instead of alcohol use.
- Incorrect sequences of instructions could impair the person’s equilibrium. Therefore, if a police officer tells the person to close their eyes and then tilt their head back, the test results could be invalid.
Without standardization, the results of a finger-to-nose test at a DUI stop can be inaccurate. Furthermore, without standard instructions to guide officers in judging the “clues” they observe during the test, it is impossible to know whether a police officer judged the person’s responses too harshly.
A DUI defense attorney can argue that the inherent defects in the finger-to-nose test make the results inconclusive, especially if there is no other evidence that the driver was intoxicated.
Talk with a DUI defense lawyer if your DUI arrest was based partially on a finger-to-nose test. You may have a strong defense that could result in a dismissal of charges.
It is not uncommon for people arrested on suspicion of a California DUI to mistaken believe that it is in their best interest to flatly refuse the breathalyzer. Not knowing the correct thing to do in this scenario can be the difference between becoming convicted of a California DUI and not, and unfortunately, the right thing to do is a little more complicated than merely refusing the breathalyzer or not.
When people refer to a “breathalyzer” during a California DUI stop, they actually referring to two different tests. The first is the roadside breathalyzer, often called a preliminary screening alcohol test or “PAS” test, and the second is the “chemical breath test.”
According to California Vehicle Code section 23612(h), the PAS test “indicates the presence or concentration of alcohol based on a breath sample in order to establish reasonable cause to believe the person was driving [under the influence]…[it] is a field sobriety test and may be used by an officer as a further investigative tool.”
The PAS roadside breath test, like other field sobriety tests such as the walk-and-turn test, the horizontal gaze nystagmus test, and the one leg stand test, are optional. Although an officer might threaten to arrest someone for refusing the optional breathalyzers, a driver should stand their ground and politely refuse to complete any field sobriety tests. Despite what the officer might say, they are optional and are only meant to give the officer the evidence they need to arrest the driver.
In fact, the officer must advise the driver that the roadside breath test is optional. California Vehicle Code section 23612(i) states that “If the officer decides to use a [PAS], the officer shall advise the person that he or she is requesting that person to take a [PAS] test to assist the officer in determining if that person is under the influence. The person’s obligation to submit to a [chemical test under California’s Implied Consent Law] is not satisfied by the person submitting to a [PAS] test. The officer shall advise the person of that fact and of the person’s right to refuse to take the [PAS] test.”
As stated above, providing a breath sample to an officer during the PAS test only give the officer the evidence they need to arrest a driver. Whether a driver provides the officer that information or not, the officer will have to make the decision to arrest a driver on suspicion of a DUI or not. In order to arrest a driver on suspicion of a California DUI, the officer must have probable cause. The probable cause can consist of driving patterns indicative of intoxication, bloodshot eyes, slurred speech, smell of alcohol on a driver’s breath, admissions of drinking or intoxication, and, yes, a reading of the pass test indicating a BAC of 0.08 percent or higher.
If the officer meets the probable cause standard by obtaining and/or observing enough evidence that a driver is driving under the influence, the officer can lawfully arrest the driver on suspicion of driving under the influence. Once this happens, California’s Implied Consent law takes effect.
California’s Implied Consent law, codified in California Vehicle Code section 23612(a)(1)(A), “A person who drives a motor vehicle is deemed to have given his or her consent to chemical testing of his or her blood or breath for the purpose of determining the alcohol content of his or her blood, if lawfully arrested for an offense allegedly committed in violation of [California’s DUI laws].”
Simply put, if you have a license and you drive in California, you have impliedly consented to submit to the chemical test after you have lawfully been arrested for a DUI, which can either be a breath test or a blood test. If the driver opts not to give blood, then they must provide a breath test. Conversely, if a person opts against the breath test, they must submit to the blood test.
So should you pass on the breathalyzer?
Pass on the roadside “PAS” test. Submit to the chemical test required under California’s Implied Consent law (See Breath or Blood Test After a California DUI Stop).
Memorial Day just past and summer is around the corner. Summer months mean beach trips, vacations, barbeques, 4th of July, and this year, my personal favorite, the World Cup. Where there is fun to be had, law enforcement expects drunk and impaired driving. Many of the summer activities I just mentioned do, often, involve indulging in the alcoholic beverage, possibly even a little of the Mary Jane now that’s it’s legal here in California. One of law enforcement’s favorite weapons in their battle against impaired driving is the sobriety checkpoint.
The 4th Amendment of the United States Constitution requires that officers have probable cause and a warrant before they can seize and/or search a person. Well, what is a checkpoint? It is certainly a seizure since the police are stopping people on the roads when they would otherwise be free to drive without interruption. It may be also a search if the law enforcement has drivers take a breathalyzer. So how can law enforcement do this without having a warrant?
In the 1987 case of Ingersoll v. Palmer, the California Supreme Court set forth guidelines to ensure the constitutionality of checkpoints in California. Those guidelines are as follows:
- The decision to conduct checkpoint must be at the supervisory level.
- There must be limits on the discretion of field officers.
- Checkpoints must be maintained safely for both the officers and the motorists.
- Checkpoints must be set up at reasonable locations such that the effectiveness of the checkpoint is optimized.
- The time at which a checkpoint is set up should also optimize the effectiveness of the checkpoint.
- The checkpoint must show indicia of official nature of the roadblock.
- Motorists must only be stopped for a reasonable amount of time which is only long enough to briefly question the motorist and look for signs of intoxication.
- Lastly, the Court in the Ingersoll decision was strongly in favor of the belief that there should be advance publicity of the checkpoint. To meet this requirement law enforcement usually make the checkpoints highly visible with signs and lights.
Three years later in the case of Michigan Department of State Police v. Sitz, the United States Supreme Court held that the state’s interest in preventing drunk driving was a “substantial government interest.” It further held that this government interest outweighed motorists’ interests against unreasonable searches and seizures when considering the brevity and nature of the stop. In doing so, the court held that sobriety checkpoints were constitutional even though officers were technically violating the 4th Amendment.
Now that we’ve determined that sobriety checkpoints are constitutional, I would be remiss if I did not tell you what your rights and obligations are, as the driver, should you happen to find yourself stopped at a sobriety checkpoint.
Based on the last of the Ingersoll v. Palmer requirements, checkpoints must be highly visible. As a result, drivers are often aware of the checkpoint before they drive up to it. Believe it or not, drivers are allowed to turn around so as to avoid the checkpoint. They, however, must do so without breaking any traffic laws such as making an illegal U-turn.
If you do not turn away, but rather pull up to the checkpoint, the officer might first ask you some questions such as: Where are you coming from? Where are you going? Have you had anything to drink?
The 5th Amendment to the Constitution gives you the right not to say anything to law enforcement ever. And don’t! Invoke your right to remain silent by telling the officer, “I would like invoke my 5th Amendment right and respectfully decline to answer any of your questions.” Now keep you mouth shut until given the opportunity to call your attorney.
Surely this is not going to sit well with the officer. They may, at that point, have the driver exit the car and request that they perform field sobriety tests. Drivers should absolutely decline to perform the field sobriety tests. They are an inaccurate indicator of intoxication, but fortunately they are optional. I and many other people would have trouble doing them sober.
At this point, the officer is likely fuming, but who cares? You are exercising your constitutional rights.
As a last-ditch effort, they may request that you take a roadside breathalyzer commonly referred to as a “PAS” (preliminary alcohol screening) test. Under California’s implied consent rule, as a driver, you must submit to a chemical test after you have been arrested on suspicion of a DUI. The key word is “after.” Therefore, when you happen upon a checkpoint and the officer requests that you to take the PAS test, you can legally refuse. If, however, the officer has arrested you on suspicion of DUI you must submit to either a blood test or a breath test.
This summer season be on the lookout for sobriety checkpoints. But should you find yourself about to drive through a checkpoint with no way to legally turn around, know your rights and use them. That’s what they’re there for.
Let’s imagine a common DUI scenario.
A person is stopped on suspicion of a California DUI. The person stopped has read my many posts telling readers that the field sobriety tests are optional and should not be submitted to. So they politely decline the field sobriety tests. Then the officer requests an on-scene breathalyzer known as the “preliminary alcohol screening” test or PAS test. In addition to my posts reminding readers that this too is option, the officer also informs the driver that the PAS test is optional. So this too is politely declined by the driver. Lastly, the officer advises the driver that they are under arrest on suspicion of a California DUI and that, by law, they must submit to a chemical test which can either be a breath or a blood test.
Which test should the driver choose? Breath or blood?
The DUI blood test is much more accurate than the DUI breath test. The blood test is far less likely than a DUI breath test to produce a false reading. Another benefit of a DUI blood test is that the law requires that a sample of the blood is saved for future testing by the DUI suspect’s defense attorney. The defense attorney can have the sample tested by its own blood analyst to contradict the results of the prosecutor’s analyst. This is called a “blood split” and it is commonly used in DUI defense.
The blood test, however, is not infallible. See my previous post:
Since the blood test is more accurate, if a person knows that they have not had much to drink and they are fairly certain that they are under the legal limit of 0.08 percent, then a blood test might be the better option. On the other hand, the blood test might not be the best for someone who is clearly over the legal limit because it will be more difficult to dispute the test results.
Unlike the blood test, the breath test is rather unreliable. Breath tests can provide false readings for several reasons. See Lawrence Taylor’s post:
Although California DUI attorneys cannot dispute the reliability of breathalyzers as a whole during a DUI trial, they can provide evidence that the particular breathalyzer used in an individual case was inaccurate.
Unlike the blood test, the breath test may be a better option for someone who knows they are likely over the legal limit because it will be easier for a California DUI attorney to refute the results. However, many people who are actually under the legal limit may still test over the legal limit because of the same inaccuracies.
Simply put, if you are fairly confident that your blood alcohol content will below the legal limit of 0.08 percent, you’re probably better off opting for the blood test because it will accurately show that you were, in fact, under the legal limit. However, if you think there is a chance that you could be above the legal limit, you might be better off opting for a breath test so that your attorney can challenge the results if you test above the legal limit.