What should you do?
Keep left of the island and stay in your lane as the road splits, slowing if the alignment is tight.
How to recognise it
Yellow diamond with an island shape at the top and two curved arrows, one going up on the left and one coming down on the right.
Common confusion
Do not confuse it with the dual carriageway ends sign, which warns of the opposite change where the carriageways come together.
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.
