DUI Field Sobriety Testing


Officers have several tests that they use in order to determine sobriety.  Some of these, such as the Walk and Turn or the One Leg Stand Test are used in some of the officer’s first interactions with a driver they suspect of DUI.  Police departments do try to make these tests uniform and reliable so that they will be admissible in court.  The National Highway Transportation Safety Administration (NHTS) has given instructions on how the Walk and Turn and One Leg Stand Test should be administered and scored.  The following are their instructions for giving a reliable test.  Bear in mind that these are not laws or statutes that police are required to follow exactly, but it is the opinion of a very reputable government administration who has offered these guidelines.  Officers across the country are trained based on these guidelines.  They are used in training manuals and guidebooks and are often referred to in court as evidence for or against a valid test.  Now for the guidelines from NHTS:

 

Walk and Turn

Provide each DUI suspect this precise instruction:

PLACE YOUR LEFT FOOT ON THE LINE AND THEN YOUR RIGHT FOOT IN FRONT OF IT LIKE THIS. (Demonstrate heel-to-toe position).

When the DUI suspect takes this position, continue with the instructions. ONCE I TELL YOU TO BEGIN, TAKE NINE HEEL-TO-TOE STEPS DOWN THE LINE, TURN AROUND, AND TAKE NINE HEEL-TO-TOE STEPS BACK.

TURN BY KEEPING ONE FOOT ON THE LINE AND THEN USE YOUR OTHER FOOT TO TURN…LIKE THIS. Demonstrate by taking three or four heel-to-toe steps-then turning around by pivoting your left foot on the line and taking four steps with your right foot, as shown-then resuming the heel-to-toe position. Note that this is a very easy way to turn, but the suspect must follow the instructions.

KEEP YOUR HANDS AT YOUR SIDES, WATCH YOUR FEET AT ALL TIMES, AND COUNT YOUR STEPS ALOUD. DO YOU UNDERSTAND?

Don’t continue until the DUI suspect indicates he/she understands, but at the same time do not repeat the whole set of instructions. You may repeat part of the instructions or answer the DUI suspect’s questions about how to perform the test. If the DUI suspect does not watch his feet, remind him.

(Once the suspect indicates understanding, say…)

BEGIN AND COUNT YOUR FIRST STEP FROM THE HEEL-TO-TOE POSITION AS “ONE.”

How to Score The Test:You may observe a number of different behaviors when a suspect performs this test. Research, however, has demonstrated that the behaviors listed below are the most likely to be observed in someone with a BAC of 0.10 percent or more. In scoring this test, give only one point for each item observed (even if it is observed more than once) with a maximum score of 9 points.

1.    Cannot keep balance while listening to the instructions. Two tasks are required at the beginning of this test. The suspect must balance heel-to-toe on the line and, at the same time, listen carefully to the instructions. Typically, the person who is intoxicated can do only one of these things. He may listen to the instructions, but not keep his balance. Score this item if the suspect does not maintain the heel-to-toe position throughout the instructions. Do not score this item if the suspect sways or uses his arms to balance but maintains the heel-to-toe position.

2.    Starts before the instructions are finished. The intoxicated person may also keep his balance, but not listen to the instructions. Since the first words you said in giving instructions for this test were: “When I tell you to being,” score this item if the subject does not wait. Other aspects of not listening to the instructions are included in the other items.

3.    Stops while walking to steady self. The suspect pauses for several seconds after one step. Do not score this item if the suspect is merely walking slowly.

4.    Does not touch heel-to-toe. The suspect leaves a space of one half inch or more between the heel and toe on any step. Also score this item if the suspect does not walk straight along the line.

5.    Steps off the line. The suspect steps so that one foot is entirely off the line. Only count this item once, even if the suspect steps off several times.

6.    Use arms to balance. The suspect raises one or both arms more than six inches from his sides in order to maintain his balance.

7.    Loses balance while turning. The suspect removes the pivot foot from the line while turning. That is, score this item if both feet are removed from the line. Also score this item if the suspect clearly has not followed directions in turning; for example, he pivots in one movement instead of the four step movement that he was instructed to perform.

8.    Incorrect number of steps. Score this item if the suspect takes more or less than nine steps in each direction.

9.    Cannot do the test. Score this item if the suspect steps off the line three or more times, is in danger of falling, or otherwise demonstrates that he cannot do the test.

If this item is scored, the suspect gets 9 points for this test, the maximum score.

Should the DUI suspect have difficulty with this test, (for example, if he steps of the line) have him repeat the test from the point of difficulty, not from the very beginning. This test tends to lose its sensitivity if it is repeated several times.

Observe the DUI suspect from three or four feet away and remain motionless while he performs the test. Being too close or excessive motion on your part will make it more difficult for the suspect to perform, even if he is sober.

If the DUI suspect scores two or more points on this test, classify his BAC as above 0.10 percent. Using this field sobriety test, you will be able to correctly classify about 68 percent of your suspects with respect to whether they are drunk driving. Your decision point on the Walk-and-Turn Test is two clues.

Test Conditions for the DUI Walk and Turn

This field sobriety test should be given on level ground, on a hard, dry, non-slippery surface, and under conditions in which the DUI suspect would not be in danger of falling. Require him to perform the test elsewhere, or confine your decision to the results of the Gaze Nystagmus Test if these conditions cannot be met.

Some people have difficulty with balance even when sober. People more than 60 years of age, more than 50 pounds, overweight, or with physical impairments that affect their ability to balance should not be given this field sobriety test. Individuals wearing heels more than two inches high should be given the opportunity to remove their shoes.

The Walk-and-Turn Test requires a line that the suspect can see. If a natural line is no present, draw one in the dirt with a stick or on the sidewalk with chalk. Walking parallel to a curb is also adequate.

The DUI suspect must be able to see to perform this test. That is, his eyes must be open, and a nighttime adequate lighting must be available. If you can see the suspect clearly, then the lighting is adequate; otherwise, use a flashlight to illuminate the line.

Requesting that the suspect watch his feet makes the test more difficult for the intoxicated person. Be sure that the suspect is doing so, or make an immediate correction. Individuals who cannot see out of one eye may also have trouble with this test because of poor depth perception.

 

One Leg Stand Test

Provide the DUI suspect the exact instructions listed below:

1.    STAND WITH YOUR HEELS TOGETHER AND YOUR ARM DOWN AT YOUR SIDES LIKE THIS (Demonstrate how you want the suspect to stand).

2.    WHEN I TELL YOU, RAISE ONE LEG ABOUT SIX INCHES OFF THE GROUND AND HOLD THAT POSITION. AT THE SAME TIME COUNT RAPIDLY FROM 1001 TO 1030, while watching your foot. Like this.

3.    DO YOU UNDERSTAND? (Do not continue until the suspect indicates that he understands.) BEGIN BY RAISING EITHER YOUR RIGHT OR YOUR LEFT FOOT.

(At the end of the count or after about 30 seconds, if the count is slow, tell the person to put his foot down-if necessary.)

How to Score The One Leg Stand Field Sobriety Test

Research has found that the behaviors listed below are most likely to be observed in someone with a BAC of 0.10 percent or higher. In scoring this test, give only one point for each item observed, even if it is observed more than once. The maximum possible score on this test is five points.

1.    The suspect sways while balancing. This refers to a side-to-side or back-and-forth motion while the suspect maintains the one leg-stand position.

2.    Use arms for balance. He moves his arms six or more inches from the side of his body in order to keep this balance.

3.    Hopping. He is able to keep one foot off the ground, but resorts to hopping on the anchor foot in order to maintain balance.

4.    Puts foot down. The suspect is not able to maintain the on-leg-stand position, putting his foot down one or more times during the 30-second count.

5.    Cannot do test. Score this item if the suspect puts his foot down three or more times during the 30-second count or otherwise demonstrates that he cannot do the test. If you score this item, give the suspect five points-the maximum for this test.
Remember that time is critical in this test. Research has shown that a person with a BAC of 0.10 percent can maintain his balance for up to 25 seconds, but seldom as long as 30.

If the person stopped for DUI scores two or more points on the One-Leg-Stand, there is a good chance his BAC is 0.10 percent or higher. So your decision point on this test is two. Using that standard, you will correctly classify about 65 percent of the people you test as to whether they are sober or drunk driving.

Test Conditions for The One Leg Stand

As with the Walk-and-Turn Test, the One-Leg-Stand should be given on level ground, on a hard, dry, non-slippery surface, and under conditions in which the DUI suspect will be in no danger should she fall. If these guidelines cannot be followed at the place where you stop the driver, you may be able to move to a better location. If not, base your decision on the Gaze Nystagmus Test alone.

Certain individuals are likely to have trouble with this test even when sober. People over 60 years of age often have very poor balance. (Since very few elderly people are stopped at roadside, specific guidelines have not been established for them on this test). This also applies to people who are more than 50 or more pounds overweight and to those with physical impairments that interferes with balance.

In administering this field sobriety test, make certain the DUI suspect’s eyes are open and that adequate lighting exists. If you can see the suspect fairly well, then the light is adequate. Otherwise, use a flashlight to illuminate the ground. In total darkness, the one leg-stand is difficult even for a sober person.

Observe the suspect from about three feet away and remain relatively motionless while he is performing the test. Being too close just as in the Walk-and-Turn Test makes the test more difficult. And, again, individuals with heels over two inches high should be given the opportunity to remove their shoes.

If the suspect puts his foot down, instruct him to continue to count from the point at which the foot touched the ground. And if the person counts very slowly, stop the test after 30 seconds have elapsed.

 

Horizontal Gaze Nygstagmus Test

One test the is sometimes employed in the field in order to determine sobriety is the Horizontal Gazy Nystagmus Test (HGN).  The idea of this test is that when an intoxicated person moves their eyes to the side, jerking of the eyes will occur before 45 degrees and the person will not be able to follow a slowly moving object smoothly with their eyes.  While this test is not used to determine an exact BAC, it can be used for “probable cause” and general evidence.  It is important that you consult with a Los Angeles DUI Lawyer to understand the applicability and admissibility of the HGN test in your case.  Following are guidelines that are often given to officers in order to teach them how to administer the test correctly and also to teach them how to score the test (decide if you’re drunk or not):

How to Administer the Horizontal Gaze Nystagmus Test:

Give the DUI suspect the following instructions from a position of interrogation (that is, with your weapon away from the suspect):

1.    I AM GOING TO CHECK YOUR EYES. (Request that the DUI suspect remove glasses or hard contact lens at this time if they are being worn. Nystagmus is not influenced by how clearly the suspect can see the object he is to follow.)

2.    NOW KEEP YOUR HEAD STILL AND FOLLOW THIS (indicate what he is to follow) WITH YOUR EYES. DO NOT MOVE YOUR EYES BACK TO THE CENTER UNTIL I TELL YOU. (If the DUI suspect moves his head, use a flashlight or your free hand as a chinrest.)

3.    Check the suspect’s right eye by moving the object to the suspect’s right. Have the suspect follow the object until the eyes cannot move further to the side. Make this movement in about two seconds, and observe:

  • 1.    whether the DUI suspect was able to follow the object smoothly or whether the motion was quite jerky; and
  • 2.    how distinct the nystagmus is at the maximum deviation.

4.    Move the object a second time to the 45-degree angle of gaze, taking about four seconds. As the subject’s eye follows the object, watch for it to start jerking. If you think you see nystagmus, stop the movement to see if the jerking continues. If it does, this point is the angle of onset. If it does not, keep moving the object until the jerking does occur or until you reach the imaginary 45-degree angle. Note whether or not the onset occurs before the 45-degree angle of gaze. (The onset point at a BAC of 0.10 percent is about 40 degrees).

If the DUI suspect’s eyes start jerking before they reach 45 degrees, check to see that some white of the eye is still showing on the side closest to the ear, as in the photograph. If not white of the eye is showing, you either have taken the eye too far to the side (that is, more than 45 degrees) or the person has unusual eyes that will not deviate very far to the side. Use the criteria of onset before 45 degrees only if you can see some white at the outside of the eye.

Repeat this entire procedure for the DUI suspect’s left eye. When observing the left eye at 45 degrees of gaze, some white of the eye again should be visible at the outside (closest to the ear) of the eye.

NOTE: Nystagmus may be due to causes other than alcohol in three of four percent of the population. These other causes include seizure medications, phencyclidine (PCP), barbiturates and other depressants. A large disparity between the performance of the right and left eye may indicate brain damage.

Scoring

Watch for three signs on intoxication in each eye. Give one point for each item checked for a maximum of six points.

1.    Onset of alcohol gaze nystagmus in the right eye occurs before 45 degrees. Do not score this item unless some white is visible on the outside of the right eye (closest to the ear) at the point of onset.

2.    Nystagmus in the right eye when moved as far as possible to the right is moderate or distinct. Do not score this item if you only see the faint jerking that occurs at the onset point.

3.    The right eye cannot follow a moving object smoothly. If you score this item, be sure that the jerkiness was not due to your moving the object in a jerky manner.

4.    Onset of alcohol gaze nystagmus in the left eye occurs before 45 degrees. If you score this item, be certain that some white is visible on the outside of the left eye (closest to the ear) at the point of onset.

5.    Nystagmus in the left eye when the eye moves as far as possible to the left is moderate or distinct.

6.    The left eye cannot follow a moving object smoothly.If the DUI suspect scores four or more points out of the six possible points on this test, classify his BAC as above 0.10 percent. (NOTE: Yes, the limit for Kansas is .08, but when the tests were studied, they were used to establish .

Using this criterion you will be able to correctly classify about 77 percent of you suspects with respect to whether they are drunk driving. That probability was determined during limited laboratory and field-testing and is given simply to help you weigh the various sobriety tests in this battery as you make your arrest decision.

Last Updated on Saturday, 04 September 2010

DUI Field Sobriety Testing
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