How Standardized DUI Field Sobriety Tests Fail to Determine Driving Impairment


If you’ve been pulled over, subject to a field sobriety test, and subsequently arrested for a DUI, there are some important things you need to know about the DUI standardized tests that were used to gauge your level of driving impairment. In this article, the Milwaukee DUI drunk driving lawyers at the law firm of Vanden Heuvel & Dineen, S.C., will explain how these tests might be inaccurate measurements of your ability to drive.

Many scientists have concluded that there is “not a single study” that meaningfully links the Standardized Field Sobriety Tests (SFSTs) to actual driving impairment. In addition, the National Highway Traffic Safety Administration (NHTSA), the United States Department of Transportation (DOT), and NHTSA-commissioned researchers have not stated or proven that these standardized tests can reliably indicate one’s level of driving impairment. In fact, they only state, “Driving a motor vehicle is a very complex activity that involves a wide variety of tasks and operator capabilities. It is unlikely that complex human performance, such as that required to safely drive an automobile, can be measured at roadside.”

There has even been one study that has concluded that “even valid, behavioral tests are likely to be poor predictors … of actual behind-the-wheel driving.”

Even some police agencies agree with the point, at least with respect to the horizontal gaze nystagmus test (HGN), that there are some SFSTs that do not accurately gauge driving impairment. An example is the California Highway Patrol Manual, which states that the HGN test is not a psychophysical test, and that HGN’s indicators are not meant to be considered to be signs of driver impairment.

Whether or not you get a guilty verdict in your DUI trial can hinge largely on DUI standardized tests and the prosecution’s interpretation of the results, but many of these SFSTs are problematic because they fail to accurately determine driving impairment. This is why you need an experienced and dedicated Milwaukee DUI drunk driving lawyer who will point out inconsistencies in the SFSTs to fight for your acquittal. If you’re not already represented by a lawyer, contact the Milwaukee DUI drunk driving lawyers at Vanden Heuvel & Dineen, S.C. today for a free initial consultation.