Standardized Field Sobriety Tests (FST’s)

Digby Law Firm - Field Sobriety TestsThe National Highway Traffic Safety Administration has established three tests as the Standardized Field Sobriety Test. You may find a rogue officer who throws something else at you, but because the standardized tests are mostly likely to hold up in court, these are the ones you’ll probably encounter.

The Horizontal Gaze Nystagmus (HGN) Test

You’ve seen this test in movies and public service announcements. It’s the one where the officer has you watch a moving a pen or a flashlight. Nystagmus is an involuntary shaking of the eyes that usually only occurs at the extremes of your periphery. But when a person is intoxicated, it can occur at less steep angles. So the officer will have your eyes follow the object, slowly, back and forth. He or she will be watching for jerkiness in the way your eyes track the object, looking for that telltale shake when they’re off at the sides. If nystagmus occurs within 45 degrees of center, you could be in trouble. A person without nystagmus should be able to follow the object smoothly, and when they look at a still object at 45 degrees, they should be able to do so steadily. If you failed this test, you likely have a blood-alcohol content (BAC) of 0.08 or greater. The NHTSA estimates this test to be 88-percent accurate. But here’s the thing: There are literally hundreds of known causes of nystagmus, most of which have nothing to do with intoxication. Some people’s eyes just behave that way, which must be rather inconvenient for sober people at a DWI check.

The Walk-and-Turn (WAT) Test

You’ve probably seen this one, too. The cop tells you to “walk the line,” taking nine heel-to-toe steps, while looking down and counting out loud. At nine steps, you pivot on one foot, turn around, and walk nine heel-to-toe steps back. You have to keep your hands at your sides, your eyes down, and you can’t stop, waver, or really screw it up at all. This is what’s known as a “divided attention” test. The striatum, a part of the brain linked to multitasking, is compromised when someone drinks to excess. The effect is severe when the attention span is divided between mental and physical tests. The NHTSA website says the officer is looking for eight signs of impairment.

You’re in trouble if you:

  • 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

There are a lot of things to remember here. That’s the idea, in addition checking your balance, the officer is looking at how accurately you can follow instructions. Alcohol has a serious impact on the hippocampus, the part of the brain associated with the creation of new memories. It’s hard to follow multiple instructions if you’re having a hard time remembering what they are. The NHTSA claims the Walk-and-Turn test is 79 percent accurate.

The One-Leg Stand (OLS) Test

Like the Walk-and-Turn test this is a divided attention test that also checks to make sure you won’t fall flat on your face. You are instructed to stand with one foot about six inches off the ground, and count aloud by one-thousands until you’re told to lower your foot. The officer times you for 30 seconds. He or she will look for four main indicators of intoxication: Swaying while balancing, using arms to balance, hopping to maintain balance, and putting the foot down. It is 83 percent accurate.

Combined, the NHTSA claims that those three tests are 91 percent accurate.

Things to Remember

In Arkansas a person is not required to take ANY tests of ANY kind while they are at their vehicle. This includes all FST’s and the portable breath test (PBT). There is no law requiring you to take them and there is no punishment for not taking them. It is probably better for most people not to take any of these tests. The officer will often say that they will let you go if you pass these tests. In all the DWI’s I see, less than 5% of people pass these tests, even the sober people. You are however required to take the blood, breath or urine test at the police station. If you do not take that test, your license will be suspended for 6 months and you will be charged with a refusal. Also, you are not required to answer any questions the officer asks you, except to provide your personal information. Don’t help him convict you. Refuse to answer any other questions he asks. Be polite and state, “I’m not answering any questions.” You have the right to remain silent. Hopefully you will have the ability.