Detour sign used in Singapore

Detour sign used in the United States

A detour or (British English: diversion) is a (normally temporary) route taking traffic around an area of prohibited or reduced access, such as a construction site. Standard operating procedure for many roads departments is to route any detour over roads within the same jurisdiction as the road with the obstructed area.

On multi-lane highways (e.g., freeways, expressways, city streets, etc.), usually traffic shifts can replace a detour, as detours often congest turn lanes.