Law Enforcement Caselaw and Statutes: DWI Detection and Standardized Field Sobriety Testing One Leg Stand Divided Attention Test

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

One Leg Stand

Divided Attention Test

Mental Task and Physical Task

• Instructions stage

• Balance and counting stage

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F. One Leg Stand

Test Stages

Like all divided attention tests, One Leg Stand has two stages.

They are:

• Instructions stage

• Balance and counting stage

Both stages are important, because they can affect the subject's overall performance on

the test.

Notes:_______________________________________________

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Notes:_______________________________________________

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Notes:_______________________________________________

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HS 178 R5/13 49 of 62

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

One Leg Stand

8-81

Test Conditions

One Leg Stand requires a reasonably dry, hard, level, and non-slippery surface.

Subject's safety should be considered at all times.

Standardizing this test for every type of road condition is unrealistic. The original

research study recommended that this test be performed on a dry, hard, level, nonslippery

surface and relatively safe conditions. If not, the research recommends:

• subject be asked to perform the test elsewhere, or

• only HGN be administered

However, recent field validation studies have indicated that varying environmental

conditions have not affected a subject’s ability to perform this test.

The original SCRI studies suggested that individuals over 65 years of age; people with

back, leg or inner ear problems; or people who are overweight by 50 or more pounds

may have difficulty performing this test. Less than 1.5% of the test subjects in the

original studies were over 65 years of age. There was no data containing the weight of

the test subjects included in the final report. Also, the SCRI studies suggest that

individuals wearing heels more than 2 inches high should be given the opportunity to

remove their shoes.

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

One Leg Stand

8-82

Notes:_______________________________________________

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Notes:_______________________________________________

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Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

Administrative Procedures

Instructions stage:

• Stand straight, feet together

• Keep arms at sides

• Maintain position until told otherwise

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Instructions Stage: Initial Positioning and Verbal Instructions

Initiate the test by giving the following instructions, accompanied by demonstrations.

Please stand with your feet together and your arms down at the sides, like this.

Do not start to perform the test until I tell you to do so.

Do you understand the instructions so far?

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

Administrative Procedures

(Cont.)

Balance and counting stage:

• Raise either leg

• Keep raised foot approximately six inches

(15 cm) off ground

• Keep both legs straight and arms at your

side

• Keep eyes on raised foot

• Count out loud in the following manner:

“one thousand one, one thousand two, one

thousand three and so on”, until told to

stop

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Demonstrations and Instructions for the Balance and Counting Stage

Explain the test requirements, using the following verbal instructions, accompanied by

demonstrations:

When I tell you to start, raise either leg with the foot approximately six inches off the

ground.

Keep both legs straight and your arms at your side.

While holding that position, count out loud in the following manner: “one thousand one,

one thousand two, one thousand three,” and so on until told to stop.

Notes:_______________________________________________

_____________________________________________________

Notes:_______________________________________________

_____________________________________________________

HS 178 R5/13 51 of 62

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

Administrative Procedures

(Cont.)

Balance and counting stage:

• Raise either leg

• Keep raised foot approximately six inches

(15 cm) off ground, foot pointed out

• Keep both legs straight and arms at your

side

• Keep eyes on raised foot

• Count out loud in the following manner:

“one thousand one, one thousand two, one

thousand three and so on”, until told to

stop

8-85

Keep your arms at your sides at all times and keep watching the raised foot.

Do you understand?

Go ahead and perform the test. (Officer should always time the 30 seconds. Test should

be discontinued after 30 seconds.)

Observe the subject from a safe distance. If the subject puts the foot down, give

instructions to pick the foot up again and continue counting from the point at which the

foot touched the ground. If the subject counts very slowly, terminate the test after 30

seconds.

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

One Leg Stand Test Clues

• Sways while balancing

• Uses arms to balance

• Hopping

• Puts foot down

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Test Interpretation

You may observe a number of different behaviors when a subject performs this test. The

original research found the behaviors listed below are the most likely to be observed in

someone with a BAC at or above 0.08. When administering the One Leg Stand test, we

look for certain specific behaviors. Each behavior or action is considered one clue.

There is a maximum number of 4 clues on this test. Look for the following clues each

time the One leg Stand test is administered.

The subject sways while balancing. This refers to side to side or back and forth motion

while the subject maintains the one leg stand position.

Slight tremors of the foot or body should not be interpreted as swaying.

Notes:_______________________________________________

_____________________________________________________

Notes:_______________________________________________

_____________________________________________________

HS 178 R5/13 52 of 62

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

One Leg Stand Test Clues

• Sways while balancing

• Uses arms to balance

• Hopping

• Puts foot down

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Uses arms to balance. Subject moves arms 6 or more inches from the side of the body

in order to keep balance.

Hopping. Subject is able to keep one foot off the ground, but resorts to hopping in order

to maintain balance.

Puts foot down. The subject is not able to maintain the one leg stand position, putting

the foot down one or more times during the 30 second count.

If the subject puts the foot down, give instructions to pick the foot up again and continue

counting from the point at which the foot touched.

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

One Leg Stand Test Clues

• Sways while balancing

• Uses arms to balance

• Hopping

• Puts foot down

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If subject can't do the test, record observed clues and document the reason for not

completing the test, e.g. subject’s safety.

Remember that time is critical in this test. The original SCRI research has shown a

person with a BAC above 0.10 can maintain balance for up to 25 seconds, but seldom

as long as 30.

Notes:_______________________________________________

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Notes:_______________________________________________

_____________________________________________________

HS 178 R5/13 53 of 62

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

One Leg Stand Test Criterion

2 or more clues indicates BAC

at or above 0.08 (83% accurate)

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Based on recent research, if an individual shows two or more clues or fails to complete

the One Leg Stand, there is a good chance the BAC is at or above 0.08. Using that

criterion, you will accurately classify 83% of the people you test as to whether their

BAC's are at or above 0.08.

Observe the subject from a safe distance and minimize movement during the test so as

not to interfere. If the subject puts the foot down, give instructions to pick the foot up

again and continue counting from the point at which the foot touched the ground. If the

subject counts very slowly, terminate the test after 30 seconds.

Review of Divided Attention Definition

One Leg Stand is another field sobriety test that employs divided attention.

The subject's attention is divided among such simple tasks as balancing, listening, and

counting out loud.

Although none of these is particularly difficult in itself, the combination can be very

difficult for someone who is impaired.

Session 8 - Concepts and Principles of the Standardized Field Sobriety Tests (SFST)

DWI Detection and Standardized Field Sobriety Testing

One Leg Stand Test

Demonstration

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Test Demonstrations

Notes:_______________________________________________

_____________________________________________________

Notes:_______________________________________________

_____________________________________________________

HS 178 R5/13 54 of 62 Source: DWI Detection and

Standardized Field

Sobriety Testing

March 2013 Edition

Law Enforcement Caselaw and Statutes

October 29, 2015

DWI Detection and Standardized Field Sobriety Testing One Leg Stand Divided Attention Test

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