In plain English
Get ready to give way to traffic coming from your right, pick your lane early, and keep things smooth. The sign buys you time to plan.
Where you'll see it
On the approach to roundabouts, especially fast rural ones where you need to lose speed early.
The common trap
Mixing this up with the blue mini-roundabout circle. The triangle warns a roundabout is coming; the blue circle is an order at a mini one.
Memory anchor
Three arrows chasing each other in a circle — traffic going round and round.