What is the purpose of a Detour sign?

• A. To indicate a detour after a road section is closed.
• B. To indicate a pedestrian crossing ahead.
• C. To indicate an alternate route in advance of any road section that has been closed or blocked.
• D. To indicate road work only.

Answer: (C)

Detour signs guide drivers to an alternate route before a road section is closed or blocked. They’re placed in advance so motorists can smoothly switch onto the detour and follow the posted route, which helps maintain traffic flow and keep the work zone safe. This purpose matches the idea of directing drivers around closures ahead of time. The other options describe different signs: pedestrian crossing ahead, road work only, or a detour that would appear after a section is already closed, none of which capture the proactive, route-changing function of a detour sign.