Wiktionary
pace setter
n. 1 (context racing English) The runner or driver or rider in the lead. 2 (context military English) An individual, selected by the column commander, who travels in the lead vehicle or element to regulate the column speed and establish the pace necessary to meet the required movement order'''Joint Publication 1-02 ''U.S. Department of Defense Dictionary of Military and Associated Terms; 12 April 2001 (As Amended Through 14 April 2006).'''''.