ONAWA, Iowa – March 5, 2026 – Crews will be closing the Iowa 175 bridge over Interstate 29 (Exit 112) west of Onawa on Monday, March 16, until Monday, March 30, weather permitting, so work can continue on the bridge maintenance project, according to the Iowa Department of Transportation’s Sioux City construction office.
When the Iowa 175 bridge is closed you will follow a marked detour route as follows:
- Eastbound Iowa 175: At Exit 112 (Onawa/Iowa 175), head south on I-29 towards Council Bluffs to Exit 105 (Blencoe/Monona County Road E-60) where you will head east on Monona County Road E-60 to the northbound I-29 ramp and then head north on I-29 back to Exit 112 (Onawa/Iowa 175).
- Westbound Iowa 175: At Exit 112 (Onawa/Iowa 175), head north on I-29 towards Sioux City to Exit 120 (Whiting/Monona County Road E-24) where you will head west on Monona County Road E-24 to the southbound I-29 exit and then head south on I-29 back to Exit 112 (Onawa/Iowa 175).
Additional Details
- I-29 traffic will be in a head-to-head pattern during the duration of the maintenance project.
- This bridge closure is a phase of the entire maintenance project. Once the bridge is opened back up to traffic, the maintenance project will continue with one lane open on the bridge.
- The project is anticipated to be completed by Friday, May 1, weather permitting.
- Once the bridge maintenance project is completed, the lane closure that has been in place on the bridge will no longer be in place.
The Iowa DOT reminds motorists to drive with caution, obey the posted speed limit and other signs in the work area, and be aware that traffic fines for moving violations are at least double in work zones. As in all work zones, drivers should stay alert, allow ample space between vehicles, and wear seat belts.
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For general information about this closure, please contact Sarah Tracy, District 3 transportation planner, at 712-274-5831 or sarah.tracy@iowadot.us.