Attorney Paul Key
Over 20 Years of Experience

The Real Secrets of Field Sobriety Testing

April 29, 2012

By Paul Key on April 29, 2012 2:27 PM

I recently read an article in Gizmodo titled The Secrets of Field Sobriety Testing. It was interesting to see this topic discussed by someone who is neither a lawyer or someone in law enforcement. The article described the three "standardized" field sobriety tests and even had a link to the following video, which purports to demonstrate a proper walk-and-turn field sobriety test:

As I will discuss and is made readily apparent in this video, the real secret law enforcement doesn't want you to know about these field sobriety tests is that the officers performing them frequently don't know what they're doing and are administering anything but a standardized test.

The National Highway Traffic Safety Administration (NHTSA) developed these tests and claims to have completed several validation studies which purport to show that these tests work for detecting intoxication. Even NHTSA, however, qualifies the validation, stating that the tests are only valid when "administered in the prescribed, standardized manner." It makes sense, right? If someone is administering a test in a manner other than what has been validated and prescribed, then it's not a standardized test. It's something other than standard.

The validations studies were based on having subjects perform the tests in the prescribed, standardized manner and then checking their blood-alcohol levels to see if, in fact, they were above .10 and, later, .08.

Following are the standardized, prescribed instructions for the walk-and-turn test:

"Place your left foot on the line" (real or imaginary)

"Place your right foot on the line ahead of the left foot, with heal of right foot against toe of left foot." Demonstrate.

"Place your arms down at your sides." Demonstrate.

"Keep this position until I tell you to begin. Do not start to walk until told to do so."

"When I tell you to start, take nine heal-to-toe steps, turn, and take nine heal-to-toe steps back." (Demonstrate 3 heel-to-toe steps.)

"When you turn, keep the front foot on the line, and turn by taking a series of small steps with the other foot like this." Demonstrate.

"While you are walking, keep your arms at your sides, watch your feet at all times, and count your steps out loud."

"Once you start walking, don't stop until you have completed the test."

"Do you understand the instructions?" (Make sure the suspect understands.)

"Begin, and count your first step from the heal-to-toe position as 'one.'"

You'll notice that the officer is to give specific verbal instructions and physically demonstrate the proper execution of the instructions. There are a lot of instructions, to be sure, but the theory is that, when given these instructions, which are repetitive and redundant, and when the instructions are accompanied by a correct demonstration, then a non-intoxicated person should be able to perform the test without making more than one of the following mistakes:

  • cannot keep balance while listening to the instructions
  • begin before the instructions are finished
  • stop while walking to regain balance
  • do not touch heel-to-toe
  • step off the line
  • use your arms to balance
  • make an improper turn
  • take an incorrect number of steps

The problem with field sobriety testing, is that officers infrequently give the correct instructions. I reviewed over 1000 DWI arrests in Collin County, Texas, and it is the exception to find an officer who can administer these tests correctly. In many cases, it doesn't really matter because the person is so obviously intoxicated that you don't even need the test. There are many cases, however, where the the person looks just fine on the video but the officer claims that he is intoxicated based solely on mistakes the officer claims he made on the test. In those cases, improper administration of the test can result in incorrect conclusions by the officer and an unlawful arrest for DWI.

One of the biggest mistakes officers make is by not warning the subject adequately about not starting the test before told to do so. It is perfectly normal to start to do something you're being told to do. It's why we play "Simon Says" and "Mother May I." For the walk-and-turn test, the officer is supposed to warn the subject three different times to not start until told to begin:

(1) "Keep this position until I tell you to begin.

(2) Do not start to walk until told to do so."

(3) "When I tell you to start, take nine heal-to-toe steps, turn, and take nine heal-to-toe steps back." (Demonstrate 3 heel-to-toe steps.)

The theory is that, if you've been warned three times to not start until told to do so, you should be able to remember that, if you're not intoxicated. NHTSA's claims that their studies validate this aspect of the test. What if you only warn the subject one time, as frequently happens? Will a sober person forget and start without being told, the same as we frequently do when playing Simon Says? Nobody knows.

The embedded video is interesting because the officer conducting the test makes two mistakes that could very well lead a subject to make two mistakes, which the officer will incorrectly attribute to intoxication.

First, the officer does not properly demonstrate the test when he demonstrates the three steps. Officers are trained to demonstrate three steps exactly as they are to be performed by the subject. This officer fails to count his steps out loud. If the subject does the same, then the officer will mark it down as a clue of intoxication. "Well, I gave the instruction," would surely explain the officer at trial, but it's not enough to simply give an instruction. Nobody's done any validation studies to see what happens when only instructions are given without a correct demonstration.

Second, the officer fails to give the crucial, final instruction to "count your first step from the heel-to-toe position as 'one.'" This instruction is rarely given by officers in the field. In my experience in Collin County, maybe 1 in 20 tests administered contain this instruction. This instruction is important because many non-intoxicated people will count their right foot, which is already in front of their left, as "one," which means the step that they take with their left foot is "two." The person will have only taken seven steps, therefore, according to the officer, which is a clue, and the person will also end up with his right foot in front when he goes to turn, which makes it impossible to do a proper turn, which results in another clue. By failing to give that instruction, the officer has baked in two clues, which, according to his training, is an indication of intoxication.

Even if you accept the premise that properly administered field sobriety tests are trustworthy indicators of intoxication, the bottom line is that there rarely properly administered, and, therefore rarely good for much, unless you've got someone on the video who is so apparently intoxicated that you don't even need the tests.

I advise my clients to refuse to take them. Don't even take the eye test. The officer can't make you. If the officer asks you why you won't take them, tell him, Because Paul Key said that you probably don't know what you're doing and will confuse your incompetence with my being intoxicated." That probably won't keep you from being arrested, but, then, nothing probably would have, anyway, at that point.

Whether you took that advice or not, if you were arrested for driving while intoxicated in Collin County, give my office a call.