Total bridges
374
Public highway bridges in Benton County
County profile · official public datasets
Benton County, IA
374 public highway bridges tracked in the FHWA National Bridge Inventory: 34.2% rated Good, 42.8% Fair, 23% Poor.
- 374
- Public bridges
- 34.2%
- Good condition
- 23%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Benton County pairs a higher-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.
- 64th
- of 99 on Poor share
- 23%
- Poor-condition share
- 374
- public highway bridges
- 1984
- avg year built
Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.
Benton County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Benton County ranks #64 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 23%). Benton County, Iowa contains 374 public highway bridges. Roughly 34.2% are rated “Good,” 42.8% “Fair,” and 23% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.
Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.
Source: FHWA National Bridge Inventory. See methodology for full definitions.
Good condition
34.2%
128 of 374 rated 7-9
Fair condition
42.8%
160 of 374 rated 5-6
Poor condition
23%
86 of 374 rated 4 or below
In-state Poor-share rank
#64 of 99
Among Iowa counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 374 NBI-tracked bridges by lowest applicable component rating.
Good 34.2% (128)
Fair 42.8% (160)
Poor 23% (86)
Benton County's Poor-condition bridges carry 35,803 vehicle crossings a day
That is 14.2% of the county's reported daily bridge traffic on 23% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 416 crossings a day against 956 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.
Computed over the 374 of 374 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
29.1% of Benton County's bridges have passed the 50-year mark
109 of the 374 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 34.2% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.
Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.
One structure carries 21.2% of the county's Poor-condition bridge traffic
US 30 over PRAIRIE CREEK, built 1950, carries 7,600 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 86-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 35,803 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Benton County's bridges were built
374 bridges with a recorded construction year, grouped by decade
- 1900s 7
1900–1909
7 bridges
- 1920s 3
1920–1929
3 bridges
- 1940s 9
1940–1949
9 bridges
- 1950s 32
1950–1959
32 bridges
- 1960s 25
1960–1969
25 bridges
- 1970s
1970–1979
63 bridges
- 1980s
1980–1989
84 bridges
- 1990s
1990–1999
75 bridges
- 2000s
2000–2009
34 bridges
- 2010s 28
2010–2019
28 bridges
- 2020s 14
2020–2029
14 bridges
What this shows Construction peaked in the 1980s, when 84 of the county's bridges still in the inventory were built, which is 22.5% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year is 1984, 5 years newer than the Iowa average of 1979.
How Benton County compares with Iowa's closest counties by inventory size
The 5 Iowa counties nearest Benton County in number of bridges, with their condition splits. Its 23% Poor share is the 4th-lowest of these 6. Its average build year of 1984 against a peer-group mean of 1981 is in line with the group.
Showing the 5 closest of 98 Iowa counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Jasper County | 382 | 38.5% | 32.5% | 29.1% | 1977 |
| Benton County (this page) | 374 | 34.2% | 42.8% | 23% | 1984 |
| Clinton County | 372 | 66.7% | 30.4% | 3% | 1986 |
| Johnson County | 372 | 39.5% | 50.3% | 10.2% | 1979 |
| Fayette County | 362 | 35.1% | 40.3% | 24.6% | 1974 |
| Dubuque County | 346 | 50.6% | 40.8% | 8.7% | 1989 |
Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to Benton County's. Source: FHWA National Bridge Inventory, 2024 release.
Nationwide counties with similar inventory size or average build year
Two NBI-derived peer sets for Benton County, both outside Iowa so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IA (374 bridges here).
- Baltimore city County, MD · 374 bridges
- Rankin County, MS · 374 bridges
- Cape Girardeau County, MO · 374 bridges
- Monroe County, WI · 374 bridges
Similar average build year
Nearest mean year-built outside IA (1984 here).
- Hennepin County, MN · avg 1984 · 936 bridges
- Duval County, FL · avg 1984 · 831 bridges
- El Paso County, CO · avg 1984 · 686 bridges
- Bell County, TX · avg 1984 · 660 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
All bridges (374)
FM
PoorOver: MUD CREEK
084112101, Benton, IA
Built 1955 Load: 30.0 t ADT: 200
FM
PoorOver: ROCK CREEK
086122401, Benton, IA
Built 1985 Load: 30.0 t ADT: 430
FM
PoorOver: PRAIRIE CREEK
085101005, Benton, IA
Built 1967 Load: 30.4 t ADT: 550
LOCAL (LWC)
PoorOver: STREAM
083112902, Benton, IA
Built 1977 Load: 30.6 t ADT: 34
FM
PoorOver: PRATT CREEK
086113602, Benton, IA
Built 1956 Load: 30.7 t ADT: 540
FM (LWC)
PoorOver: SMALL STREAM
085120502, Benton, IA
Built 1980 Load: 31.1 t ADT: 20
LOCAL
PoorOver: BR WILDCAT CK
084102702, Benton, IA
Built 1957 Load: 31.3 t ADT: 15
FM
PoorOver: PRAIRIE CREEK
082110801, Benton, IA
Built 1959 Load: 31.6 t ADT: 45
LOCAL
PoorOver: WEASEL CK
082100701, Benton, IA
Built 1957 Load: 31.7 t ADT: 28
FM
PoorOver: OPOSSUM CREEK
084101601, Benton, IA
Built 1959 Load: 32.3 t ADT: 1,090
FM
PoorOver: HINKLE CREEK
085113201, Benton, IA
Built 1962 Load: 32.6 t ADT: 570
4TH ST
PoorOver: HINKLE CREEK
085101700, Benton, IA
Built 1973 Load: 32.7 t ADT: 3,197
13 AVE
PoorOver: BUCKEYE CREEK
082122204, Benton, IA
Built 1976 Load: 32.9 t ADT: 1,002
LOCAL
PoorOver: MUD CREEK
084111502, Benton, IA
Built 1976 Load: 33.0 t ADT: 26
FM
PoorOver: PRAIRIE CREEK
082101402, Benton, IA
Built 1961 Load: 33.3 t ADT: 766
FM (LWC)
PoorOver: SMALL STREAM
086100702, Benton, IA
Built 1990 Load: 34.4 t ADT: 330
LOCAL
PoorOver: BR PRAIRIE CK
082110502, Benton, IA
Built 1958 Load: 35.9 t ADT: 25
FM
PoorOver: HINKLE CREEK
085112804, Benton, IA
Built 1988 Load: 36.4 t ADT: 530
FM
PoorOver: PRATT CREEK
086112502, Benton, IA
Built 1989 Load: 36.9 t ADT: 540
30 AVE
PoorOver: SMALL NATURAL STREAM
082091710, Benton, IA
Built 1958 Load: 41.5 t ADT: 1,561
FM
PoorOver: DRY CREEK
083091102, Benton, IA
Built 1961 Load: 42.6 t ADT: 1,444
LOCAL
PoorOver: DRY CREEK
083091202, Benton, IA
Built 1976 Load: 45.5 t ADT: 39
LOCAL
PoorOver: STEIN CK
084121704, Benton, IA
Built 1999 Load: 51.2 t ADT: 11
FM
PoorOver: PRAIRIE CREEK
082112101, Benton, IA
Built 1960 Load: 62.9 t ADT: 820
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.