Detours and Alternate Routing
When a route is closed, road users need somewhere to go. A good detour is continuous, clearly signed, and appropriate for who is using it — vehicles, trucks, transit, pedestrians, cyclists, and emergency responders.
Last reviewed: June 24, 2026
Why It Matters
- A closure without a clear alternate route pushes road users into confusion and unsafe workarounds, and generates complaints.
- Different users need different detours — a truck route, a transit reroute, and a pedestrian path are not interchangeable.
When It Applies
- Whenever a closure removes a route that vehicles, transit, pedestrians, cyclists, or emergency responders normally use.
Planning Considerations
- Design a continuous detour for each affected user type, verify it can carry the traffic, and check signal and neighborhood impacts.
- Preserve emergency and business access, and coordinate transit reroutes with the transit agency.
Field Considerations
- Sign the detour clearly from beginning to end so users are never left guessing, and monitor how it performs.
- Adjust for unexpected congestion or access problems, within the approved plan.
Inspection Considerations
- Inspectors confirm the detour is continuous, signed, and appropriate for each user, and that emergency and business access is maintained.
Common Compliance Failures
- A detour that dead-ends or loses its signing partway.
- No separate provision for pedestrians, cyclists, or transit.
Upstream Prevention
- Plan and verify a continuous, signed detour for each user type before the closure.
- Coordinate transit, emergency, and business access in advance.
Related Pages
Relevant Signs on MUTCDSignChart.com
For individual sign codes, meanings, and specifications, see the sister site MUTCDSignChart.com. The signs below link directly to their reference pages:
Official Sources
Frequently Asked Questions
What is a detour?
A detour is a temporary route that directs traffic around a closed road using a different set of streets, marked with signs so road users can follow the alternate path. It is used when a road is fully closed.
Who approves a detour route?
A detour is generally reviewed and approved by the agency with jurisdiction over the roads involved, and a detour that crosses jurisdictions may need coordination with more than one agency. Confirm the requirement with the governing agency.