Presence of a police road block ahead. All traffic must slow down and prepare to be stopped.
Where you will see it
On the approach to a police road block, commonly on open roads and at the edge of a town.
What to do
Slow down and prepare to be stopped, as the sign says. Come down to a speed that lets you halt well short of the officers, and wait to be waved on rather than filtering past the vehicle in front.
