Traffic circle.
What is the difference between roundabout and traffic circle?
Differences between roundabouts and traffic circles
The centre island of a roundabout is smaller than the centre island of a traffic circle. The roundabout has been designed with a tighter curve around the island to encourage lower speeds and may have a sloped curb to allow more room for larger commercial vehicles.
Who calls a roundabout a traffic circle?
Rotaries, traffic circles or however you know them, they're often frustrating for American motorists. They are designed to lessen accidents, but that's not always the effect. In New England, they're called rotaries; in New Jersey, traffic circles; and in much of the rest of the English-speaking world, roundabouts.