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What are the DWI Tests Called?

One of the most common questions asked about DWIs is for information about the DWI Tests. There are three “standard” tests police officer have you perform during a DWI investigation. These three tests are: HGN (“eye” test), Walk-and-turn (walking test), and One-Leg Stand. There are other tests that police sometimes use, but they are non-standardized tests. However, even the “standardized” tests are plagued with issues.

What are the DWI Tests?

Before making any judgement on the “accuracy” of the tests, it might help to know exactly *what* the tests are.

The DWI Eye Test – HGN

The first of the three “standardized” tests is the HGN. This stands for “Horizontal Gaze Nystagmus” but is more commonly called the “eye” test. During this test an officer might have a pen-light or might use a finger illuminated by a flashlight. The officer will move the light or the finger to the left and right. The purpose of the test is to see if there is any involuntary jerking of the eye. There is a second part of the test that looks for “vertical” nystagmus, but that is not considered “standardized” like the HGN.

The Walking Test – Walk-and-Turn

The second of the three SFSTs is the Walk-and-Turn test. The name is fairly self-explanatory, but many people simply call this the “walking” test. During this test the officer wants you to walk in a straight line. That may sound simple, but the extra instructions make this test more difficult and annoying. Not only do officers want you to walk in a straight line, they want you to do in in a *very* specific way. This test requires “heel-to-toe” steps, not normal steps. Additionally, officer’s expect you to maintain the “heel-to-toe” stance while they are giving you the instructions. In other words, the test begins before the test actually begins. Officers also want you to turn a very specific way during the test, by taking a small series of steps rather than a full pivot. The 8 clues for the walk-and-turn are:

  1. Not keeping balance during instructions
  2. Starting too soon
  3. Stopping while walking
  4. Missing heel to toe
  5. Stepping off line
  6. Using arms to balance
  7. Turning improperly
  8. Wrong number of steps

One-Leg Stand

The last of the three “standard” tests is the One-Leg Stand. The name of the test explains itself, and unlike the walk-and-turn there isn’t really a “trick” to the instructions. During this test the officer wants you to stand on one leg. Simple enough, right? There are a few specifics to the instructions, such as holding your foot at least 6 inches off the ground. The “clues” that officers look for are whether you used arms to balance, were swaying during the test, hopped during the test and whether you put your foot down *at all* during the test.

Non-Standard DWI Tests

There are many non-standard tests. By “non-standard” it means that there is no specific (read: national) way to have suspects do the tests and therefore they are not supposed to be given as much weight. Some of the non-standard tests include:

  • Finger-to-nose test
  • Finger Count test
  • Alphabet test
  • Counting test

Are the DWI Tests Accurate?

Let me answer your question with another question. Do these look more like balance tests to you? If they do, then you already see how problematic these tests can be. Even more, many of the “clues” appear to be more about following directions rather than looking impaired. For example, you might take the heel-to-toe steps perfectly and have great balance, but “fail” the test simply because you took 12 steps instead of nine (just to show that you could and looked fine doing it) and for making an “improper” pivot turn. In other words, going the extra mile might actually have the opposite effect.

Another question you might want answered is what “standardized” means. The HGN, Walk-and-Turn and One-Leg Stand are “standardized” because some studies determined that those three tests are the best way to estimate impairment. Don’t let that fool you! These “studies” are very much a point of contention. Despite what many may think, these tests have *ZERO* correlation with driving ability. In other words, these tests *DO NOT* have *ANYTHING* to do with your ability to drive a car. Another reason why these tests are problematic is because of bias. Most of the studies involved controlled environments with ideal conditions, while during actual arrests the conditions vary wildly. Further, most of these studies were funded or controlled by NHTSA or other police agencies (who have incentive to justify their own behavior).

In short, the answer to the above question is “no” because of the problems surrounding both the “validation” studies and the tests themselves. The SFSTs are junk science.

More about Mimi Coffey & The Coffey Firm

When people look for a Top DWI Attorney or Best DWI Attorney, they look for experience, certification, and respect in the legal community. Mimi Coffey is a nationally-renowned trial attorney, board-certified in DWI by the NCDD. She has been practicing for over 24 years and is an author of multiple DWI Defense textbooks. She is also a national and state-wide lecturer on the law.

The Coffey Firm handles a wide variety of cases, including Unlawful Carrying Weapon (UCW), Assault (including family violence), and Possession charges. We can also help you try to get a DWI off your record or avoid probation revocation. The Coffey Firm offers fair DWI payment plans and free consultations.

Mimi is also listed on several “top criminal lawyer near me” directory listings such as Wise County DWI Lawyers, Tarrant County DWI LawyerDallas County DWI attorney, Collin County DWI attorneys and Parker County DWI attorneys. Mimi is a caring DWI Lawyer in Dallas – Fort Worth. She is also involved in the Texas Tech School of Law foundation and enjoys using the skills she has developed to give back to the community.