Chicane

Chicane: A chicane is a barrier or extra turn, usually incorporated into a race course for increased safety, to slow the vehicles and/or force then to pass through in single file. A chicane might also be a barrier build on a residential street to slow traffic (traffic calming).

He'd felt the first hairpin leading out of the city, but was still waiting for the downhill chicane [?] that prefaced rejoining the main highway.