At a roadracing event, a member of the officiating crew (or trackday organizer'
s staff) who watches the exit of corners for motorcycle (or other vehicle) crashes.
Generally, cornerworkers hold flags to regulate the racetrack - red, black,
blue, yellow,
green, checkered, and meatball flags - and are equipped with
fire-extinguishers and radios, and a strange will to stand in the hot sun all day while people crash all around them at over 150 MPH.