Walckner Law Office

​Attorney James Walckner​​

Massachusetts police officers are trained to administer a series of tests to evaluate whether drivers are impaired.  These field sobriety tests (FST’s) were designed to be successfully performed by the average sober person, and are said to test the mental and physical capabilities needed to safely operate a motor vehicle.  More specifically, FST’s allow police officers to evaluate a driver’s balance, information processing, short-term memory, vision, small muscle control, and coordination.  Proper administration of FST’s tests a driver’s divided attention that requires concentration in one area while performing another task.


After studies by the National Highway Traffic Safety Administration, three tests were found to reliably distinguish drivers having blood alcohol content (BAC) above 0.10%.  Those tests are: (1) Horizontal Gaze Nystagmus, (2) 9-Step Walk and Turn, and (3) the One-Leg Stand.  Other tests often used by police officers, including recitation of the alphabet, thumb-to-finger touch test, and touching of nose are have not been scientifically validated.

​Standardized Field Sobriety Tests (FST)