Standardized Field Sobriety Tests: Why do Police Officers Request People Who Are Suspected of DUI/DWI To Perform Them? a Maryland DUI/DWI Attorney I have become very accustomed to analyzing a client’s performance on the standardized field sobriety tests (at least the police officer’s version of that performance) to determine its legal significance. There are two reasons why police officers request that people suspected of DUI or DWI request the suspect to the perform the standardized field sobriety tests which are the Horizontal Gaze Nystagmus Test (HGN), the Walk and Turn and the One Leg Stand. There are certainly other tests that police officers asks suspect to perform in these situations such as alphabet, counting and finger dexterity tests but the three listed above are the standardized tests recommended by the NTSB.

The primary reason that police officers ask suspects to perform these tests is to allow the officer to develop probable cause to arrest the suspect or at least take him or her into custody and charge them accordingly. The reason for this is that the smell of alcohol alone is not generally considered to be enough to establish probable cause. The police officer will typically run the suspect through the tests and based on his assessment of the person’s performance, either take the person into custody or release him.

The second reason why police officers request that the suspect perform field sobriety tests is to develop evidence to be used against the suspect at trial. Assuming that the police officer details the poor performance in his report, this evidence is usually more than sufficient to convict the suspect of DUI or DWI, even in the absence of a breath or blood test.

A colleague of mine contacted me yesterday to get my take on a DUI case that he was handling in Baltimore County that illustrates the importance of reviewing the client’s performance on the field sobriety tests carefully. The facts of the case were that the defendant was pulled over for driving on the shoulder of I695. There was road construction and as a result the traffic was backed up. The defendant was getting off at the next exit which was only a quarter mile or so up the road, so he drove on the shoulder to the exit and was pulled over.

The officer noted in his report that he detected a moderate odor of alcohol coming from the driver upon approaching the vehicle. He asked the defendant to exit the vehicle and perform the standardized field sobriety tests. He wrote in his report that the defendant displayed six out of six clues on HGN. He noted that he performed the one leg stand satisfactorily and than ,other than executing the turn incorrectly which nearly everyone does, he also performed the walk and turn as he was instructed.

Based on these observations the officer took him into custody and transported him to the police station. The defendant agreed to submit to a breath test and blew a .09. My colleague advised me that the State had offered him a plea to the lesser included offense of driving while impaired, and agreed not to oppose a probation before judgment. He advised me that he was inclined to recommend that his client take the offer but wanted to know what I thought about the case.

I certainly don’t mean to try to take credit for another attorney’s win. Most good criminal defense attorneys, including me, routinely consult other attorneys on their cases and very often the consulted attorney points out something that the attorney handling the case has overlooked. Having said that, in this case I immediately told my colleague that he should reject the offer. My reasoning was that probation before judgment was a virtual certainty under these facts regardless of whether the client takes a plea or loses at trial and as such I didn’t think he had anything to lose by trying the case. I suggested to him that he had a very good shot at having the .09 test result suppressed as the product of an illegal arrest which would very likely result in a not guilty verdict. The reason for this is, as I wrote above, the primary purpose of the standardized field sobriety tests is to allow the police officer to develop probable cause to arrest. In this case the defendant had performed very well on both the one leg stand and the walk and turn. Moreover, the Court’s have held that HGN only establishes the presence of alcohol or drugs in the system and that the presence of nystagmus does not in and of itself establish probable cause. As noted herein, the court’s have also held that the smell of alcohol alone does not establish probable cause.

My colleague took the case to trial in the District Court. The judge agreed that the defendant’s performance on the field sobriety tests did not establish probable cause. He suppressed the .09 breath test result and the client was found not guilty.

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