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I 129 over Missouri River & I-29

Woodbury County, Iowa · rated Fair in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

I 129 over Missouri River & I-29 in Woodbury County, Iowa, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the superstructure, rated 5 (fair condition) on the 0-9 scale.
It was built in 1976, making it 49 years old at the 2025 inventory.
It carries about 15,800 vehicles a day (traffic count year 2022).
Its listed owner is the state highway agency.
It is one of 182 of the 455 inventoried bridges in Woodbury County rated fair (40.0%); 95 (20.9%) are rated poor.
A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.

Component ratings


Structure	Continuous steel girder and floorbeam
Length	about 2,606 ft
Location	0.5 Mi.w.of JCT.29
NBI structure number	000000000600765
Condition class	Fair

Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.

Bridge	Built	Vehicles/day	Condition
I29 NB Off Ramp over Perry Creek Conduit	2017	91,000	Good
US 77 over Missouri River & Rd	1981	34,600	Fair
I 29 Ia 12 over Drainage-all of Roadway	1957	32,900	Fair
US 77 over I 29 & Ia 12 NB	2012	26,900	Good
I 29 SB over Pierce St Frontage Rd	2018	21,100	Fair
Ia 12 over BNSF Rvr Sts & Ia 376	1936	20,600	Poor