The National Highway Traffic and Safety Administration (NHTSA) conducted research to validate research concerning several field sobriety tests. Please note: all information referenced to “NHTSA” is from their February 2006 Edition, DWI Detection and Standardized Field Sobriety Testing.
I am using the language from NHTSA and DWI Detection and Standardized Field Sobriety Testing, because law enforcement is trained with this information and book. I want you, the reader, to see what law enforcement if being told about DUI investigations, because you have more likely than not, been subjected to a DUI related investigation conducted in part based on techniques and procedures attributed to NHTSA.
NHTSA directs the officer to administer three scientifically validated field sobriety tests. Based on the performance on these tests, as well as the observations made concerning the driving and face to face contact, the officer must then decide whether to arrest the driver for a suspected DUI.
One of the three standardized field sobriety tests is called the “One leg stand” (abbreviated as “OLS”).
This is a divided attention test consisting of two stages:
Balance and counting stage
In the instructions stage, the person must stand with their feet together, keep arms at sides and listen to the instructions. This divides a person’s attention between balancing and information processing (listening to and remembering instructions). (All information is from Page VII-6).
In the balance and counting stage, a person must raise one leg, either leg, with the foot approximately six inches off the ground, and keep the raised foot parallel to the ground. While looking at the elevated foot, the person must count out loud in the following manner: “one thousand one, one thousand two, etc” until told to stop. This divides the person’s attention between balancing and counting out loud. (All information is from Page VII-6).
The timing for a thirty second period by the officer is an important part of the one leg stand test. The original research showed that many impaired persons were able to stand on one leg for up to 25 seconds, but that few can do so for 30 seconds. (All information is from Page VII-6).
The one leg stand is administered and interpreted in a standardized manner.
Officers must look for four specific clues:
sways during balancing (side to side or back to front)
uses arms to balance (more than six inches)
puts foot down before the test is complete (All information is from Page VII-6).
Inability to complete the one leg stand test occurs when the person
puts the foot down three or more times, during the 30 second period
cannot do the test (All information is from Page VII-7).
The original research showed that when a person produces two or more clues or is unable to complete the test, it is likely that the person’s BAC is over .10%. This criterion has been shown to accurate 65% of the time. (All information is from Page VII-7).
Procedures for the one leg stand testing per NHTSA
1. Instructions stage: initial positioning and verbal instructions for the one leg stand test
The officer must begin the test by giving the following verbal instructions, accompanied by demonstrations. All the following instructions are found at Page VIII-12:.
“Please stand with your feet together and your arms down at the sides, like this.” The officer must demonstrate.
“Do not start to perform the test until I tell you to do so.”
“Do you understand the instructions so far?” NHTSA reiterates: “Make sure suspect indicates understanding.”
2. Demonstrations and instructions for the balance and counting stage for the one leg stand test
The officer must explain the test requirements, using the following verbal instructions, accompanied by demonstrations. All the following instructions are found at Page VIII-12:
“When I tell you to start, raise one leg, either leg, with the foot approximately six inches off the ground, keeping your raised foot parallel to the ground.” (The officer must demonstrate the one leg stand.)
“You must keep both legs straight, arms at your side”
“While holding that position, count out loud in the following manner: “one thousand one, one thousand two, one thousand three, until told to stop.” The officer must demonstrate a count as follows: “one thousand one, one thousand two, one thousand three, etc.” The officer should NOT look at his or her foot while doing the demonstration because of officer safety.”
“Keep your arms at your sides at all times and keep watching the raised foot.”
“Do you understand?” NHTSA reiterates: “Make sure suspect indicates understanding.”
“Go ahead and perform the test.” (The officer should always time the 30 seconds; the test should be discontinued after 30 seconds).
If the person puts his or her foot down, give the instructions to pick the foot up again and continue counting from the point at which the foot touched the ground. If the person counts very slowly, terminate the test after 30 seconds. (All information is from Page VIII-12).
3. Test interpretation of the one leg stand test
The original research found that the clues or behaviors listed below are associated with a person most likely to be with a BAC of over .10%: All the following clues are found at Page VIII-13:
The person sways while balancing.
This refers to side to side or back and forth motion while maintaining the one leg position.
Uses arms for balance.
The person moves his or her arms six or more inches from the side of the body in order to keep balance.
The person is able to keep one foot off the ground, but resorts to hopping in order to maintain balance.
Puts foot down.
The person is not able to maintain the one leg stand position, putting the foot down one or more times during the 30 second count.
4. Test conditions of the one leg stand
The one leg stand requires a reasonably dry, hard, level and non slippery surface. (Page VIII-13).
The original research shows that persons over 65 years of age, or with back, leg or inner ear problems have difficulty in performing this test. Persons wearing heels over two inches high should be given the opportunity to remove their shoes. (Page VIII-14).
Learn more about how you can defend against your DUI arrest! Please contact an experienced DUI attorney such as Mark Blair for a free, informative and confidential consultation to develop your DUI defense! Mark has over 26 years of DUI experience and specializes in DUI defense. Mark has represented thousands of persons who have suffered a DUI arrest. Please call Mark Blair at (408) 295-4343, (650) 344-4343, (510) 845-4343, (415) 664-4343 (925) 935-4343 or (707) 252-4343.