Standard Field Sobriety Tests in Texas
The first test used by Texas officers is the “One Leg Stand”. This test, if instructed properly, is believed to have a 65% reliability of predicting that a person’s BAC is 0.10% or greater; providing the instructions are correctly given and the officer correctly demonstrates the various steps:
a) Stand with your feet together and your arms at your side.
b) Keep that position until you are told to begin.
c) The officer must ask if you understand the instructions and receive an acknowledgement from you that you do.
d) When told to start, raise either leg approximately 6 inches off the ground with your foot pointed out.
e) Keep both legs straight, arms at side.
f) Count 1,001, 1,002 etc. until told to stop.
g) Keep your arms at side and keep watching raised foot.
h) The officer must again ask if you understand the instructions and receive an acknowledgement from you that you do.
i) The officer will then start the test.
j) The test can last no more than 30 seconds of actual time.
There are four scoring factors for the one leg stand test: (1) Sways while balancing, (2) Arms for balance, (3) Hopping, (4) Puts foot down. Putting your foot down three or more times is considered reaching a “decision point” in the test. Stopping at any point during the test, does not disqualify you from an opportunity to resume.
The second test used “Walk and Turn Test.” This test is believed to possess a 68% reliability of predicting that a person’s BAC is 0.10% or greater. However, just like the one leg stand test, all of the proper instructions and officer demonstrations must be performed to ensure reliability:
a) Place your left foot on the line.
b) Place your right foot on the line ahead of your left foot, with the heel of your right foot against toe of your left foot.
c) Keep your arms to your side.
d) Keep this position until you are told to begin.
e) The officer must ask if you understand the instructions and receive an acknowledgement from you that you do.
f) When told to start, take 9 heel-to-toe steps, turn, and take 9 heel-to-toe steps back.
g) When you turn, keep the front foot on the line, and turn by taking a series of small steps with the other foot.
h) While walking, keep arms at side, watch feet at all times, and count steps out loud.
i) Once you start, don’t stop until test is completed.
j) The officer must ask if you understand the instructions and receive an acknowledgement from you that you do.
k) Begin the test and count first step from the heel-to-toe as “one”.
There are eight scoring factors for the walk and turn test: (1) Cannot keep balance while listening to instructions, (2) Starting before instructions are finished, (3) Stopping while walking, (4) Did not touch heel-to-toe (more than 1/2 inch on any step), (5) Stepped off line, (6) Used arms for balance, (7) Improper turn, (8) Incorrect number of steps.
The third, and final, test is the “Horizontal Gaze Nystagmus” (HGN), which, If instructed properly, has a 77% reliability of predicting that a person’s BAC is 0.10% or greater. Provided, of course, that all of the proper instructions are given.
- I [the officer] am going to check your eyes.
- Keep your head still and follow this stimulus with your eyes only.
- Keep following the stimulus with your eyes until I tell you to stop.
There are three scoring factors for the HGN test determined for each eye, giving a total of six total scores: (1) The Lack of Smooth Pursuit – The eyes “bounce” as they follow a smoothly moving stimulus. (2) Distinct Nystagmus at Maximum Deviation – Distinct nystagmus will be evident when the eye is held at maximum deviation for a minimum of four seconds. (3) Onset of Nystagmus Prior to 45 Degrees – The point at which the eye is first seen jerking.
Challenges to Sobriety testing can arise if concerns regarding the motorist’s mobility when exiting the vehicle, any injuries sustained previously or pre-existing conditions that might affect balance or motor skills, age and weight, clothing and the terrain on which the tests are being performed.
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