Why sober people fail Standardized Field Sobriety Tests or SFSTs
Discover the shaky science behind the Standardized DUI Field Sobriety Tests
Walk & Turn TestThis is a divided attention field sobriety test, which means that a person under the influence of alcohol is not supposed to be able to perform the test correctly, because alcohol intoxication will not allow a person to divide their attention. Original research revealed that this test, when properly administered and scored, was only 68% accurate in determining if someone was under the influence of alcohol. That means it was incorrect 32% of the time. Yes, in ideal circumstances, when performed exactly as instructed, this test was wrong 1/3 of the time. Not a very good indicator of whether someone is actually under the influence. Several problems exist with the Walk and Turn test, including the fact that it is nearly impossible to perform correctly the first time, sober or not. Here's how the test works: The officer will ask you to stand in an uncomfortable position while you listen to the instructions for what to do. If you break that stance, it is a "clue" that you are impaired. While holding a balancing stance, the officer will instruct you to perform many, many tasks. What's more, officers are taught to give these instructions in rapid order, which makes them hard to follow and remember. Any mistakes you make are additional "clues" that you are impaired by alcohol. Here's what the officer will ask you to do: Walk the line, heel to toe, for 9 steps, Turn in a specific manner, Keep your arms at your sides, Look at your feet, Count out loud, Don't stop walking, Count in the proper order, Keep your feet on the line, and Return 9 heel to toe steps to the start
1 Leg StandThe third and last standardized test in the NHTSA battery of field sobriety testing is the One Leg Stand or OLS test. This is another divided attention test. Original research revealed that this test, when properly administered and scored, was only 65% accurate in determining if someone was under the influence of alcohol. If you remember, the Walk and Turn test was only 68% accurate. Thus, the OLS test is the least accurate field sobriety test of the three. It's incorrect 35% of the time, which means, in ideal circumstances, when performed exactly as instructed, this test was wrong more than 1/3 of the time. There is also a specific category of people who were not represented in the scientific studies behind this test. Therefore, the One Leg Stand test doesn't have legitimate scientific support for some of the population. The test is essentially very basic, but very difficult if you don't have great balance. Again, the officer will give you rapid fire instructions on what to do. You are expected to do everything as instructed. For example, if you "sway" for balance, the officer will take that as a clue you are intoxicated. Give it a try right now: Raise either foot approximately 6" off the ground, keeping the bottom of the foot parallel to the ground. While looking at your foot, keep both legs straight and arms at your sides. With the raised foot in the air, count out loud from 1 to 30, saying, "One thousand one, one thousand two, one thousand three..." and so on, until the officer times you for 30 seconds. There are a total of 4 clues an officer is looking for during this test to determine if you are under the influence, including raising of the arms, swaying, hopping, and putting the raised foot down.