What should you do?
Do not drive in the closed lane beyond the signal; if you are already in it, move out safely when the signals direct you.
How to recognise it
A black square with four amber corner lamps and a red X.
Common confusion
A red X means the lane is closed, which is stricter than a flashing amber warning; treat it as a ban on using the lane.
Explanation written by the My Driving Test editorial team using the Department of Transport Traffic Signs Manual conventions and the RSA Rules of the Road.
