The Standard Field Sobriety Test (SFST) is given by police officers to drivers they suspect to be intoxicated. The test consists of three different parts: 1) the horizontal gaze nystagmus (HGN) test; 2) the one-leg stand test; and 3) the walk-and-turn test.
The SFST has existed since the 1970s, when police forces across the country began to crack down on drunk drivers more strictly. It has been scientifically validated as a way to determine a driver's state of inebriation. South Carolina courts and other courts around the country will accept the results as evidence in court for the purposes of convicting a driver of DUI. Furthermore, and contrary to popular belief, a DUI conviction can occur on the basis of SFST results, even in the absence of breathalyzer test evidence.