 The exception to this rule is if the yellow flag waves after the white flag is thrown or if the race will not be restarted (typically for rain; but sometimes for darkness if a track does not have night lights), in which case NASCAR will use video evidence to determine the finishing order.When the caution comes out, the pit lane is immediately closed, a rule first implemented following the 1989 Atlanta 500.This is shown by a flashing red light at the entrance to pit road.