Total bridges
489
Public highway bridges in Black Hawk County
County profile · official public datasets
Black Hawk County, IA
489 public highway bridges tracked in the FHWA National Bridge Inventory: 52.8% rated Good, 40.7% Fair, 6.5% Poor.
- 489
- Public bridges
- 52.8%
- Good condition
- 6.5%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Black Hawk County posts a top-10% lowest Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- Top 8%
- lowest Poor share in state
- 6.5%
- Poor-condition share
- 489
- public highway bridges
- 1983
- 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.
Black Hawk County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Black Hawk County ranks #8 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.5%). Black Hawk County, Iowa contains 489 public highway bridges. Roughly 52.8% are rated “Good,” 40.7% “Fair,” and 6.5% “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
52.8%
258 of 489 rated 7-9
Fair condition
40.7%
199 of 489 rated 5-6
Poor condition
6.5%
32 of 489 rated 4 or below
In-state Poor-share rank
#8 of 99
Among Iowa counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 489 NBI-tracked bridges by lowest applicable component rating.
Good 52.8% (258)
Fair 40.7% (199)
Poor 6.5% (32)
Black Hawk County's Poor-condition bridges carry 34,702 vehicle crossings a day
That is 2.2% of the county's reported daily bridge traffic on 6.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,084 crossings a day against 3,129 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 488 of 489 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
29% of Black Hawk County's bridges have passed the 50-year mark
142 of the 489 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 52.8% 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 24.2% of the county's Poor-condition bridge traffic
E RIDGEWAY AVE over DRY RUN CREEK, built 1950, carries 8,392 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 32-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 34,702 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Black Hawk County's bridges were built
489 bridges with a recorded construction year, grouped by decade
- 1900s 8
1900–1909
8 bridges
- 1920s 4
1920–1929
4 bridges
- 1930s 5
1930–1939
5 bridges
- 1940s 20
1940–1949
20 bridges
- 1950s 38
1950–1959
38 bridges
- 1960s 39
1960–1969
39 bridges
- 1970s 45
1970–1979
45 bridges
- 1980s
1980–1989
122 bridges
- 1990s
1990–1999
92 bridges
- 2000s
2000–2009
67 bridges
- 2010s 37
2010–2019
37 bridges
- 2020s 12
2020–2029
12 bridges
What this shows Construction peaked in the 1980s, when 122 of the county's bridges still in the inventory were built, which is 24.9% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1983) matches the Iowa average (1979).
How Black Hawk County compares with Iowa's closest counties by inventory size
The 5 Iowa counties nearest Black Hawk County in number of bridges, with their condition splits. Its 6.5% Poor share is the 4th-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1983 is in line with the group.
Showing the 5 closest of 98 Iowa counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Polk County | 545 | 57.8% | 35.8% | 6.4% | 1986 |
| Linn County | 506 | 46.4% | 47.2% | 6.3% | 1987 |
| Black Hawk County (this page) | 489 | 52.8% | 40.7% | 6.5% | 1983 |
| Woodbury County | 455 | 39.3% | 39.6% | 21.1% | 1985 |
| Sioux County | 449 | 62.4% | 34.7% | 2.9% | 1982 |
| Plymouth County | 432 | 52.1% | 26.4% | 21.5% | 1974 |
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 Black Hawk 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 Black Hawk County, both outside Iowa so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IA (489 bridges here).
- Suffolk County, MA · 489 bridges
- Shasta County, CA · 492 bridges
- Lyon County, KS · 492 bridges
- St. Clair County, IL · 486 bridges
Similar average build year
Nearest mean year-built outside IA (1983 here).
- Dallas County, TX · avg 1983 · 3,230 bridges
- Bexar County, TX · avg 1983 · 2,342 bridges
- Sedgwick County, KS · avg 1983 · 1,333 bridges
- Will County, IL · avg 1983 · 649 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
All bridges (489)
E TAMA RD
FairOver: TRIB TO MILLER CREEK
87-13-34-03-10, Black Hawk, IA
Built 1974 Load: 31.4 t ADT: 314
RICKARD RD
FairOver: TRIB TO SPRING CREEK
88-11-34-01-10, Black Hawk, IA
Built 1984 Load: 31.4 t ADT: 44
IA 57
FairOver: CEDAR RIVER
0.8 MI. W OF JCT. 218, Black Hawk, IA
Built 1974 Load: 31.5 t ADT: 14,000
IA 281
FairOver: WAPSIE RIVER OVERFLOW
2.7 MI. W OF SR V62, Black Hawk, IA
Built 1967 Load: 31.5 t ADT: 1,240
W RIDGEWAY AVE
FairOver: BLACK HAWK CREEK
CITY BRIDGE NO. 2, Black Hawk, IA
Built 1979 Load: 31.6 t ADT: 4,164
NB US 63
FairOver: CEDAR RIVER
0.2 mi N of Jct. U.S. 218, Black Hawk, IA
Built 1968 Load: 31.7 t ADT: 3,450
N UNION RD
FairOver: BEAVER CREEK
90-14-28-06-20, Black Hawk, IA
Built 1954 Load: 31.7 t ADT: 1,394
GILBERTVILLE RD
FairOver: I-380
1.2 MI. N OF JCT. SR V49, Black Hawk, IA
Built 1982 Load: 31.7 t ADT: 815
V62
FairOver: I-380
2.3 MI. N OF S.R. V65, Black Hawk, IA
Built 1984 Load: 31.7 t ADT: 314
N PILOT GROVE RD
FairOver: POYNER CREEK
89-11-20-02-10, Black Hawk, IA
Built 1984 Load: 31.9 t ADT: 59
IA 281
FairOver: ELK RUN CREEK
0.3 mi. E of Jct. SR V43, Black Hawk, IA
Built 1955 Load: 32.0 t ADT: 1,050
BUTTERFIELD RD
FairOver: DRAINAGE
000000000, Black Hawk, IA
Built 1950 Load: 32.1 t ADT: 260
RIVER FOREST RD
FairOver: I-380
0.8 MI. S OF S JCT. 218, Black Hawk, IA
Built 1981 Load: 32.1 t ADT: 330
ASHLEY RD
FairOver: TRIB TO CEDAR RIVER
87-11-07-03-10, Black Hawk, IA
Built 1983 Load: 32.3 t ADT: 44
MAIN ST
FairOver: UNIV BR DRY RUN CREEK
AT 18TH ST, Black Hawk, IA
Built 1962 Load: 32.4 t ADT: 9,191
W QUARRY RD
FairOver: ROCK CREEK
87-14-13-01-10, Black Hawk, IA
Built 1987 Load: 32.5 t ADT: 5
US 63
FairOver: DRAINAGE DITCH
3.4 MI. S OF JCT. US 20, Black Hawk, IA
Built 1960 Load: 32.7 t ADT: 5,500
US 63
FairOver: STREAM
0.7 MI. S OF JCT. 20, Black Hawk, IA
Built 1960 Load: 32.7 t ADT: 8,400
US 218
FairOver: STREAM
4.3 mi. S of Jct. U.S. 20, Black Hawk, IA
Built 1952 Load: 32.7 t ADT: 4,110
VINCENT RD
FairOver: CASTLE HILL CREEK
CITY CULVERT NO. 46C, Black Hawk, IA
Built 1988 Load: 32.7 t ADT: 684
SARAH DRIVE
FairOver: DRAINAGE
CITY CULVERT NO. 55C, Black Hawk, IA
Built 1993 Load: 32.7 t ADT: 2,967
US 20
FairOver: DRAINAGE DITCH
1.3 mi. W of jct. SR V65, Black Hawk, IA
Built 1980 Load: 32.7 t ADT: 10,700
WB US 20
FairOver: IA 58
At the Jct. Iowa #27 & 58, Black Hawk, IA
Built 1984 Load: 32.7 t ADT: 7,050
E BIG ROCK RD
FairOver: ELK RUN CREEK
89-12-03-01-10, Black Hawk, IA
Built 1963 Load: 33.0 t ADT: 49
EASTMAN RD
FairOver: TRIB TO MILLER CREEK
87-12-08-01-10, Black Hawk, IA
Built 1983 Load: 33.2 t ADT: 11
E AIRLINE HWY
FairOver: TRIB TO ELK RUN CREEK
89-11-07-01-10, Black Hawk, IA
Built 1986 Load: 33.3 t ADT: 59
S CANFIELD RD
FairOver: TRIB TO INDIAN CREEK
88-11-08-04-10, Black Hawk, IA
Built 1996 Load: 33.8 t ADT: 2,769
COTTER RD
FairOver: MILLER CREEK
87-12-04-02-10, Black Hawk, IA
Built 1986 Load: 33.9 t ADT: 59
LINCOLN RD
FairOver: TRIB TO BLACK HAWK CREEK
87-14-15-02-10, Black Hawk, IA
Built 1985 Load: 33.9 t ADT: 59
HOLMES RD
FairOver: TRIB TO ROCK CREEK
87-14-24-02-10, Black Hawk, IA
Built 1985 Load: 33.9 t ADT: 39
W TAMA RD
FairOver: GIVEN CREEK
87-14-32-01-10, Black Hawk, IA
Built 1985 Load: 34.1 t ADT: 49
US 20
FairOver: DRAINAGE
2.4 MI. E OF E JCT. I-380, Black Hawk, IA
Built 1980 Load: 34.5 t ADT: 10,700
W REINBECK RD
FairOver: TRIB TO MILLER CREEK
87-13-28-01-10, Black Hawk, IA
Built 2001 Load: 34.7 t ADT: 11
EVANSDALE DR
FairOver: I-380
AT JCT. OF EVANSDALE DR., Black Hawk, IA
Built 1982 Load: 34.7 t ADT: 4,760
I 380 NB
FairOver: IANR RR TX ST CEDAR RVR
0.4 MI. S OF JCT. 218, Black Hawk, IA
Built 1983 Load: 34.7 t ADT: 19,950
SB 218 EB 57
FairOver: CEDAR RIVER OVERFLOW
0.2 mi. E of jct. IA 27, Black Hawk, IA
Built 1974 Load: 35.1 t ADT: 9,800
EB US 20
FairOver: US 63 SERGEANT RD TRAIL
AT JCT. US 63, Black Hawk, IA
Built 1983 Load: 35.1 t ADT: 11,450
DYSART RD
FairOver: TRIB TO MILLER CREEK
88-12-19-04-10, Black Hawk, IA
Built 1981 Load: 35.2 t ADT: 1,463
WB 20
FairOver: US 218
AT W JCT. I-380, Black Hawk, IA
Built 1983 Load: 35.3 t ADT: 10,200
I380 SB FLYOVER
FairOver: US 20 & US 218
AT N JCT. 20, Black Hawk, IA
Built 1983 Load: 35.3 t ADT: 9,700
ASHLEY RD
FairOver: TRIB TO CEDAR RIVER
87-11-07-03-20, Black Hawk, IA
Built 1946 Load: 35.5 t ADT: 44
NB 218 WB 57
FairOver: CEDAR RIVER OVERFLOW
0.2 MI. E OF IA. 27, Black Hawk, IA
Built 1974 Load: 35.8 t ADT: 9,800
ANSBOROUGH AVE
FairOver: TRIB TO MILLER CREEK
87-13-33-02-10, Black Hawk, IA
Built 1988 Load: 35.9 t ADT: 15
PINE STREET
FairOver: SMALL NATURAL STREAM
42.639833 -92.456111, Black Hawk, IA
Built 1968 Load: 36.0 t ADT: 1,109
BRANDON RD
FairOver: CEDAR RIVER
87-11-19-04, Black Hawk, IA
Built 2012 Load: 36.0 t ADT: 1,542
7TH ST
FairOver: DRAINAGE DITCH
0.1 mi. S of Jct. SR C50, Black Hawk, IA
Built 1993 Load: 36.0 t ADT: 737
CO HWY D
FairOver: DRAINAGE
000000000, Black Hawk, IA
Built 1975 Load: 36.3 t ADT: 1,438
S ELK RUN RD
FairOver: ELK RUN CREEK
89-12-34-04, Black Hawk, IA
Built 1971 Load: 36.3 t ADT: 3,574
BISHOP AVE
FairOver: BLOWERS CREEK
CITY CULVERT NO. 21C, Black Hawk, IA
Built 1900 Load: 36.6 t ADT: 1,339
FM D-38
FairOver: I-380
2.8 mi. S of S Jct. US 20, Black Hawk, IA
Built 1984 Load: 36.9 t ADT: 854
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.