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Bridge conditions in Johnson County, Iowa

376 inventoried bridges · 34 rated poor · 2025 National Bridge Inventory

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

Johnson County tracks close to typical: 34 of its 376 inventoried bridges (9.0%) are rated poor, against a national rate of about 7%.

34 of the 376 bridges in Johnson County, Iowa, are rated in poor condition (9.0%) in the 2025 National Bridge Inventory, as of August 20, 2026.
156 bridges (41.5%) are rated good and 186 (49.5%) fair.
The median Johnson County bridge was built in 1980.
The busiest poor-rated bridge is Gilbert St over Ralston Creek (built 1972), carrying about 14,025 vehicles a day.

Good 41.5% · Fair 49.5% · Poor 9.0% of 376 bridges

Bridges rated poor

Every bridge in the county with a poor rating, busiest first. Poor means a major component is rated 4 or lower on FHWA's 0-9 scale; it is a repair flag, not a closure notice.

Bridge	Built	Vehicles/day	Condition
Gilbert St over Ralston Creek	1972	14,025	Poor
Ia 1 NB over Iowa River	1915	10,950	Poor
Iowa Ave over Iowa River	1916	5,400	Poor
Kirkwood Ave over Ralston Creek	1935	4,693	Poor
Dodge St over over Iais RR	1970	4,688	Poor
Washington St over Ralston Creek	1910	2,487	Poor
Johnson St over Ralston Creek	1930	2,356	Poor
Evans St over Ralston Creek	1911	2,176	Poor
FM 520TH St over Iowa River	1971	2,060	Poor
Van Buren St over Ralston Creek	1935	1,082	Poor
FM 520TH St over Pechman Creek	1974	880	Poor
Iowa Ave over Ralston Creek	1910	754	Poor
Rapid Ck Rd over Br Rapid CR	1950	490	Poor
Benton St over Ralston Creek	1935	449	Poor
Dingleberry Rd over Rapid CR	1960	398	Poor
Third Ave over So Br Ralston Creek	1957	341	Poor
Center Ave over Ralston Creek	1957	330	Poor
Center St over Hurtzel Run	1900	269	Poor
FM SW Bayrtwn R over Stream	1964	240	Poor
Sioux Ave over Stream	1966	234	Poor
FM NE Rpd Ck Rd over Br Rapid CR	1950	130	Poor
FM Amana Rd over Br Iowa River	1935	130	Poor
SW Angle Rd over Br Old Mans CR	1920	92	Poor
FM SW Naples Av over Crooked CR	1942	70	Poor
Derby Ave SW over Stream	1954	60	Poor
160TH St over Br Mill CR	1955	60	Poor
Green Castle Av over Small Stream	1900	46	Poor
SW 520TH St over Deer Creek	1900	35	Poor
Eagle Ave over Bradley CR	1915	31	Poor
120TH St over Stream	1952	30	Poor
NE 340TH St over Small	1900	11	Poor
Iowa Johnson Rd over Stream	1925	11	Poor
Maier Ave over Picayune CR	1915	10	Poor
Johnson-iowa Rd over Br Old Mans CR	1915	5	Poor

Busiest bridges in the county

Bridge	Built	Vehicles/day	Condition
I 80 EB over Iowa River	1960	32,900	Good
US 218 over Deer Creek	1970	32,400	Good
I 80 WB over Iowa River	1960	32,050	Good
EB I-80 over over US 6 & Iais RR	1995	31,000	Fair
I 80 WB over over US 6 & Iais RR	1992	31,000	Fair
EB I-80 over Cic Railway	1963	30,600	Fair
WB I-80 over Cic Railway	1963	30,600	Fair
I 380 NB over W-60 & Cric RR	1971	27,900	Fair
I 380 SB over W-60 & Cic RR	1972	27,900	Fair
US 6 over Iowa River	1957	27,600	Fair

Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.

Every bridge in Johnson County → - all 376, busiest first, each with its own condition record.

All of Iowa: Iowa bridge conditions by county · every download on the data page.

Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.