Definition of Field sobriety tests
In determining reasonable grounds for DWI arrest, many police departments use field sobriety tests in which a suspect is requested to step from his vehicle and engage in a number of physical acts which are designed to test the person’s coordination for the purpose of determining intoxication. The finger-to-nose test, picking up coins, walking a line, reciting the alphabet, and other similar activities have become a fairly common part of DWI arrest procedure.
That's the definition of Field sobriety tests in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.