The next phase of DUI investigation is something the National Highway Traffic Safety Administration (NHTSA) calls “Pre-Arrest Screening,” which seems by its name to imply that the decision to arrest has been made. “Pre-Arrest Screening” sounds like something an officer does to make sure the person being arrested doesn’t have any medical issues, and not to make sure the arrest should happen in the first place. But I digress.
The first step in the “Pre-Arrest Screening” phase is putting the driver through Standardized Field Sobriety Tests (SFSTs), or what a lot of us (law enforcement and lawyers) call “Stupid Human Tricks” after the Dave Letterman bit. The NHTSA’s spent a lot of money developing these tests over the years, and they are quick to tout the “success rate” of these tests in identifying impaired drivers. The problem is that these tests were developed in lab or lab-like settings, with sober test subjects (.00-.05% BAC) or very intoxicated ones (.15% or higher BAC). That’s not to say that they don’t have some validity, but crowing about a test’s ability to identify people with a BAC twice the legal limit strains credulity just a bit, doesn’t it?
The three Standardized Field Sobriety Tests are the Horizontal Gaze Nystagmus test (HGN), the Walk-and-Turn test (WAT), and the One Leg Stand test (OLS).