Field Sobriety Tests
So what are these "field sobriety tests" (FSTs), anyway? Are they any good? Why do we have them?
Good questions. I will answer the first below. The other two are arguable.
Field sobriety tests are largely unscientific mothods for evaluating intoxication. The theory is that intoxication impairs coordination, and so by testing coordination it is possible to determine a level of intoxication. However, because the California drunk driving statutes only allow conviction based on either driving while under the influence of alcohol or drugs, or upon driving with a blood alcohol content of 0.08% or above, these tests really don't prove anything. The test metrics themselves claim to only be accurate at indicating a probablility of a BAC over 0.10%. However, a lack of coordination can be based on a lot of factors, including disability, lack of sports training, lack of sleep, bodyweight, inner ear problems, performance anxiety, attention deficit disorder, etc.
The Standardized Field Sobriety Test Procedures, which have been adopted by the California Highway Patrol, are:
This condition is measured by asking a person to follow your finger with their eyes. Once you get out of their field of vision, they will either have a tendancy to turn their head, or if not allowed to, then their eyes will repeatedly shift back and forth at the corner of their eyes. Click the link above to read the National Highway Transportation Safety Administration's "Resource Guide for Judges, Prosecutors, and Law Enforcement."
2) Walk and Turn (WAT)
In this test, a person is asked to walk on a designated straight line following a number of instructions, including to walk heel to toe, not to being until told to, keeping arms at sides, watching feet, while counting, without stopping. If any of the instructions are not followed to the letter, including taking too many steps, balancing with your arms, "turning improperly", etc., the officer will perceive this as evidence of intoxication.
3) One Leg Stand (OLS)
A person will be asked to stand on one leg, with hands to the side, and count according to the one-thousand and one, one-thousand and two formula. The test lasts for 30 seconds. The officer is watching for balance problems, such as using your foot or hands to aid you in balancing, like any human is apt to do even when perfectly sober.
GRADING:
Each test above comprises a number of opportunities for you to make mistakes, or in other words, to give the officer "clues". The officer will tabulate his "clues", and then rely on a probability (between 65%-77%) of your intoxication if you meet the threshold number of clues for any given test.
It is important for your defense attorney to know that "in 1991, Dr. Spurgeon Cole of Clemson University conducted a study on the accuracy of FSTs. His staff videotaped individuals performing six common field sobriety tests, then showed the tapes to 14 police officers and asked them to decide whether the suspects had "had too much to drink and drive". The blood-alcohol concentration of each of the 21 DUI subjects was .00, unknown to the officers. The result: the officers gave their opinion that 46% of these innocent people were too drunk to be able drive. This study showed the possible inaccuracy of FSTs. Cole and Nowaczyk, "Field Sobriety Tests: Are they Designed for Failure?", 79 Perceptual and Motor Skills Journal 99 (1994)." [source]
OTHER FSTs, not included in the Standardized Battery are:
- Modified-Position-of-Attention (a/k/a/ the Romberg test). Here, you will be asked to close your eyes and tilt your head back, with your feet together for 30 seconds. If you have a condition of vertigo, you are likely to sustain bodily injury trying this unattended.
- Finger-to-Nose
- Recite the Alphabet
- Fingers-to-Thumbs-While-Counting
- Counting Backwards.
These tests are falling out of use as they are becoing more widely regarded as faulty, nonscientific, and too difficult to perform even while sober.
For more information, including determination of blood alcohol content (BAC) of 0.08%, 0.10% or above, click the California drunk driving/DUI defense related information links above, or below.