There are two significant closures on the Great River Road route in southeast Iowa with little or no detour signage.
One is a recent development that threatens to become long-term. The road just southeast of Montrose was washed out earlier this year. No detours have been posted. If you approach from the south, there is no easy point to turn around. You have to go three miles back to 320th Street to get any road heading west to US 61/218, and five miles back to J82 to get a paved road. The Montrose police chief has been issuing tickets to drivers caught in the barricaded section.
Lee County should set up a detour for X28 (the designation for the GRR between Keokuk and Montrose) via J82, US 62, and J72 (old IA 404) — or at the very least put up a “No access to Montrose” sign at the Sandusky corner. Great River Road travelers will miss the Galland School marker, but would at least know they can get to it and will have to turn around.
The second development happened six-plus years ago: The bridge carrying Main Street across Cascade Ravine south of downtown Burlington, commonly called the “Cascade Bridge”, is permanently closed to vehicles (and now also to pedestrians) due to age and failing condition. There are signs that warn “Downtown Traffic use Madison and Harrison”, but the GRR arrows still direct into the park and to the closed bridge.
In both cases, I believe the scenic byway signs should be changed until repairs are made to both segments.