Bridge conditions in Johnson County, Iowa
376 inventoried bridges · 34 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
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 .
- 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.
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.