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350TH Street over Drainage Ditch

Worth County, Iowa · rated Good in the 2025 National Bridge Inventory

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

350TH Street over Drainage Ditch in Worth County, Iowa, is rated in good condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the culvert, rated 9 (excellent condition) on the 0-9 scale.
It was built in 2021, making it 4 years old at the 2025 inventory.
It carries about 10 vehicles a day (traffic count year 2022).
Its listed owner is the county highway agency.
It is one of 44 of the 116 inventoried bridges in Worth County rated good (37.9%); 17 (14.7%) are rated poor.
Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
Its condition class and component ratings are unchanged from the 2024 inventory.
Its most recent inspection on record is dated December 2023, on a 24-month routine inspection cycle.
A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.

Component ratings

Component	Rating (2024)	Rating (2025)	FHWA scale meaning
Culvert	9	9	Excellent condition


Structure	Concrete culvert
Length	about 24 ft
Location	0.55 mi. W of Killdeer
NBI structure number	000000000355891
Condition class	Good
Traffic status (item 41)	Open, no restriction
Last inspection (item 90)	December 2023
Inspection interval (item 91)	24 months
Scour (item 113)	8: foundations stable, scour above the top of the footing

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

Bridge	Built	Vehicles/day	Condition
I-35 over Drainage Ditch	1972	20,600	Good
I-35 over Goose Creek	1972	20,100	Fair
NB I 35 over over UP RR	1970	10,700	Fair
SB I 35 over over UP RR	1970	10,500	Fair
NB I-35 over Elk Creek	1972	9,950	Fair
SB I-35 over Elk Creek	1972	9,750	Fair