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The Legal Use Of Field Sobriety Tests In Court

If a peace officer has reasonable grounds to believe that a person has committed a drunk driving offense as described in MCL 257.625c(1), the officer must request a chemical test. MCL 257.625a(6)(d). Generally, a police officer will develop reasonable cause through the administration of Standardized Field Sobriety Tests (SFSTs), which was discussed in my previous blog.

In this blog I will focus on the legal issues involving the battery of SFSTs approved for use by law enforcement by the NHTSA.

The Vehicle Code’s Standardized Field Sobriety Test Provisions:

The Vehicle Code includes two sections regarding standardized field sobriety tests (SFSTs) that impact drunk driving cases. MCL 257.62a defines “standardized field sobriety test” as one of the tests “validated by the National Highway Traffic Safety Administration”. MCL 257.625s codifies a rule of evidence that permits “a person who is qualified by knowledge, skill, experience, training, or education, in the administration of standardized field sobriety tests, including the horizontal gaze nystagmus (HGN) test, shall be allowed to testify subject to showing of a proper foundation of qualifications.”

Thus, these two statutes make it clear that the admission of a SFST requires them to be administered in substantial compliance with NHTSA standards. Put differently, when the officer fails to follow the NHTSA standards, then the proper remedy is suppression of the SFST results – and more importantly the evidence that follows. People v. Berger, 217 Mich. App. 213; 551 NW2d 421 (1996).

Horizontal Gaze Nystagmus (HGN):

The Michigan Court of Appeals in Berger held that HGN is scientific evidence that has general acceptance and reliability if “the test was properly administered by a qualified person.” Based on Berger, a defendant can challenge the admission of the HGN in one of two ways: (1) the test was improperly administered; or (2) the test administrator was not qualified. Each of these categories present issues that are factually based and therefore will vary in every case.

Thus, under Berger, the HGN test operator must follow the NHTSA standards in administering the HGN test — otherwise the results are inadmissible. NHTSA requires the test administrator to observe all of its factors in administering the test. If the operator fails to observe any one of the NHTSA standards in using the HGN test, then defense counsel should move for suppression of the test results and any other evidence discovered as a result of the HGN test.

Likewise, the training of the officer is the second prong to be considered under Berger. An officer’s qualifications may include: the length of time he or she was an officer; the amount of SFST training; and relevant on-the-job training. People v. Peebles, 216 Mich. App. 661, 668, 550 N.W.2d 589 (1996). If there are any holes in the officer’s qualifications, then the HGN may not be admissible.

People v. Berger can form the basis for a successful challenge to the admissibility of the results of an HGN test.

The Walk And Turn And One Leg Stand:

Both the walk and turn and one leg stand are also subject to challenge under Berger. Still, the most important factor to note here is that neither test has the same legal acceptance as the HGN. While Berger accepted the HGN as a valid scientific procedure, the Court of Appeals has never adopted or endorsed either the walk and turn or one leg stand as acceptable scientific procedures. This distinction means that to gain the admissibility of the results from the walk and turn or the one leg stand tests, the prosecution must establish these SFSTs are admissible under MRE 702. MRE 702 permits the introduction of expert testimony – such as from an officer who conducted a SFST – if the court determines that (1) the testimony is based on sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case. A challenge under MRE 702 may seem like a longshot, but a defendant who employs the right expert on NHTSA standards may be able to successfully suppress the results of both the walk and turn and one leg stand tests.

A challenge under MRE 702 tests whether or not a scientific or technical theory should be presented to the trier of fact. When faced with a proffer of scientific or technical testimony, Michigan courts apply the factors articulated in Daubert v Merrell Dow Pharmaceuticals, Inc, 509 U.S. 579, 593; 113 S Ct 2786; 125 L Ed 2d 469 (1993). See People v Kowalski, 492 Mich. 106, 120; 821 NW2d 14 (2012). Under Daubert, a trial court may consider (1) whether the theory in question has been tested, (2) whether it has been subject to peer review and publication, (3) the potential rate of error, and (4) whether the theory has gained general acceptance. Daubert, 509 U.S. at 593-594. These factors are not exhaustive, however; the inquiry is flexible, and the subject of the inquiry is the scientific validity, and therefore the relevance and reliability, of the theory in question. People v. Toepler, Mich. App. Unpub. No. 320917 (2016).

A Daubert analysis of either SFST opens the door for the defense to use expert testimony to challenge the admissibility of the results from the walk and turn and one leg stand tests. The manner of challenge – like challenges to the HGN — will be dictated by the facts of the particular situation and will likely include the defense’s use of an expert witness. In addition to the Daubert-MRE 702 challenge, a defendant can move for suppression of the walk and turn, and one leg stand tests because the tests were administered improperly or by an unqualified administrator — just like with the HGN.


Effective drunk driving defense typically involves challenges to Standardized Field Sobriety Tests. SFSTs are the go-to tool police officers rely on in drunk driving investigations to preliminarily establish reasonable cause that a driver is under the influence of alcohol. SFSTs have varying degrees of success in predicting a subject’s influence of alcohol. The most reliable SFST is the HGN with an eighty percent rate in predicting a .10 blood alcohol level in a subject. The reliability rate for the walk and turn and one leg stand drops to sixty-eight and sixty-five percent, respectively. NHTSA: Standardized Field Sobriety Tests. Yet, the most important factor in each of the NHTSA recognized SFSTs is that the officer conducting the test does so properly. A SFST that is improperly administered is akin to the old adage of “garbage in, garbage out”. An improper SFST is not reliable and should not be admissible by the trial court.

The inherent reliability of the HGN has been recognized by the Michigan Court of Appeals. This can make the suppression of HGN results more difficult for defendants. Still, police officers often fail to follow the NHTSA standards. Under MCL 257.625s and People v. Berger, HGN results should be suppressed whenever NHTSA standards are not followed. Likewise, when the HGN test operator is not qualified or properly trained, the statute and Berger require suppression.

The walk and turn and one leg stand have not been widely accepted like the HGN. As such, they can be challenged under Berger, and a variety of evidentiary issues created by MRE 702 and Daubert. What must be stressed is that NHTSA standards and SFSTs present highly technical issues for litigation. To successfully attack an officer’s incorrect use of a SFST will often require the testimony of an expert on NHTSA standards employed by the defense.

SFSTs rely on officers often operating in the dark of night by the side of the road to follow standards established by the NHTSA. In the absence of proper training or simply the errant admission of a SFST by an officer, the result can be unreliable results that are inadmissible in a drunk driving prosecution. This blog provides a few of the most common challenges to the admission of SFSTs and the subsequent results of drunk driving investigations from SFST test results.

If you are under investigation or have been charged with drunk driving, contact Satawa Law for your confidential consultation.

Mark Satawa

Mark Satawa is a criminal defense attorney specialized in forensic DNA,
sex crimes, child abuse, shaken baby, medical child abuse, white collar,
and federal crimes.