detour

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. Types Depending on the roadway affected, and the scope of construction, different types of detours may be used. The most basic is to simply close a stretch of roadway for a defined period of time, diverting all traffic around the site. Other types of detours may also be used, such as a detour that is only in effect at night, only in effect during weekends, or a detour that restricts through traffic while permitting local traffic such as residents and delivery vehicles. Which type of detour to use is decided by a variety of factors – a full closure of a road means construction can be completed more quickly, but also means a more severe impact on traffic.