Field Sobriety Tests: How Reliable Are They?

Aside from Intoxilyzer or blood tests, one of the commonly-used means of Oklahoma police to assess whether an Oklahoma driver is under the influence of drugs or alcohol are field sobriety tests. Officers typically have a suspected drunk driver perform a battery of sobriety tests; failing one or more of them can not only lead to an arrest for DUI, it can possibly also be used by the prosecution as evidence at trial.

 

Field sobriety tests are not, however, foolproof as indicators of intoxication. To begin with, they are limited in their evidentiary value. None of these tests can be used as a correlation to a specific blood alcohol content level, because they may only indicate intoxication (and not necessarily alcohol intoxication). Moreover, even a test that may seem to suggest intoxication might not hold up in court if reasonable doubt can be cast on the way that police officer conducted it.

 

Precision is key. Just as an Intoxilyzer must be properly calibrated for its results to hold up in court, field sobriety tests must be administered correctly to be valid. Even seemingly minor mistakes by the officer during the testing can open the door to challenging the test results, and a successful challenge can make the difference between a conviction for DUI or an acquittal.

 

The National Highway Transportation Safety Administration (NHTSA) establishes the requirements to properly administer field sobriety tests. These guidelines are quite precise; the inadvertent failure of a police officer to follow them properly is a definite possibility.

 

As one example, consider the “horizontal gaze nystagmus” test. This test involves instructing the test subject and then having the test subject follow the track of a stimulus object, such as a flashlight, with his or her eyes while holding still. In theory the test sounds simple to administer, but there are several ways that the police officer can commit errors that invalidate it.

 

The test itself consists of four phases and 14 passes of the stimulus object. The NHTSA requirements are specific on how the test subject is to be positioned, how far from his or her nose the stimulus object should be held, how quickly it should be moved, the maximum angle of deviation that should be used, and the minimum time that should be spent conducting the test; if it takes less than 86 seconds then it is suspect because the officer has performed it too quickly, which in turn shows that one or more of the steps was administered correctly.

 

For anyone accused of DUI in Oklahoma based at least in part on the results of field sobriety tests, what is important to know is that not only is it imperative that the police officer who administered the test followed the correct procedure with exactitude, it is also essential that the Oklahoma DUI defense attorney also be intimately familiar with the details of the test protocols. Only an experienced DUI attorney who has carefully studied the NHTSA requirements for how a valid test should be given will know what to look for when it comes to identifying ways in which the officer may have made a mistake.  The DUI Attorneys at the Hunsucker Legal Group have received the same field sobriety testing training as the police officer on the street and are versed in defending Oklahoma drivers accused of DUI or APC.  Most often, they know the Field Sobriety Manual better than the arresting officer. 

 John Hunsucker

Oklahoma DUI and APC Attorney