Where: On any road.
Purpose: To warn the driver that -
A. The road ahead may be obstructed,
B. There could be pedestrians,
C. Rescue teams and police or traffic officers controlling the traffic at the scene,
D. There could be wreckage, injured persons, animals or broken glass on the road surface.
Action: Slow down immediately, look out for someone controlling the traffic and be ready to stop. If there is enough or professional help on the scene, do not stop out of curiosity. Do not look at the collision scene or wreckage, concentrate on the route to be followed without driving over or into anything.