Home › Iowa › Carroll County › 310TH St over Small Stream

310TH St over Small Stream

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

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

310TH St over Small Stream in Carroll 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 7 (good condition) on the 0-9 scale.
It was built in 1972, making it 53 years old at the 2025 inventory.
It carries about 71 vehicles a day (traffic count year 2022).
Its listed owner is the county highway agency.
It is one of 120 of the 249 inventoried bridges in Carroll County rated good (48.2%); 17 (6.8%) 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 April 2024, 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	7	7	Good condition


Structure	Continuous concrete culvert
Length	about 21 ft
Location	082332301
NBI structure number	000000000362480
Condition class	Good
Traffic status (item 41)	Open, no restriction
Last inspection (item 90)	April 2024
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
US 30 over Ditch #77	1919	13,000	Fair
US 30 over Storm Creek	1955	7,300	Fair
US 30 over over UP RR	1982	6,800	Fair
US 30 over Middle Raccoon River	1982	6,000	Fair
US 71 over UP RR & Rd	1988	5,600	Fair
US 71 over Stream	2000	5,600	Good