The Iowa DOT plans to close IA 38 through Stanwood in two phases for construction. The official detour (PDF) runs 15 miles longer than 38 itself between Stanwood and Monticello and goes through Mount Vernon.
The local enterprising driver (but not semi drivers) may look at this and see an obvious shortcut: Go through Mechanicsville and Morley on X40 and either go east to Olin or pick up US 151 by Anamosa.