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.

Total bridges

489

Public highway bridges in Black Hawk County

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

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).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

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.

Bridge inventory size and condition shares for Black Hawk County and the 5 Iowa counties closest to it in inventory size
County Bridges Poor
Polk County 545 6.4%
Linn County 506 6.3%
Black Hawk County (this page) 489 6.5%
Woodbury County 455 21.1%
Sioux County 449 2.9%
Plymouth County 432 21.5%

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).

Similar average build year

Nearest mean year-built outside IA (1983 here).

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 489 Good 258 Fair 199 Poor 32

All bridges (489)

BAKER RD

Good

Over: CAMP CREEK

89-11-13-04-10, Black Hawk, IA

Built 2002 Load: 33.3 t ADT: 10

MERNER AVE

Good

Over: DRAINAGE

000000000, Black Hawk, IA

Built 2016 Load: 33.4 t ADT: 106

BURTON RD

Good

Over: TRIB TO CEDAR RIVER

90-13-26-02-10, Black Hawk, IA

Built 2016 Load: 33.4 t ADT: 49

ANSBOROUGH AVE

Good

Over: US 218

IN WATERLOO, Black Hawk, IA

Built 1991 Load: 33.5 t ADT: 5,414

W 18TH ST

Good

Over: CEDAR RIVER

CITY BRIDGE NO. 20, Black Hawk, IA

Built 2003 Load: 33.6 t ADT: 10,921

BIG ROCK RD

Good

Over: NO NAME CREEK

CITY CULVERT NO. 31C, Black Hawk, IA

Built 2009 Load: 33.7 t ADT: 100

BIG ROCK RD

Good

Over: NO NAME CREEK

CITY CULVERT NO. 32C, Black Hawk, IA

Built 2009 Load: 33.7 t ADT: 100

LONE TREE RD

Good

Over: US 218

1.7 mi N of IA 57 & IA 58, Black Hawk, IA

Built 1995 Load: 34.0 t ADT: 2,358

W REINBECK RD

Good

Over: ROCK CREEK

87-14-25-01-10, Black Hawk, IA

Built 1998 Load: 34.3 t ADT: 39

W CEDAR-WAPSI RD

Good

Over: CEDAR RIVER

90-14-16-05-10, Black Hawk, IA

Built 2020 Load: 34.3 t ADT: 1,178

RAMPS D & J

Good

Over: CEDAR RIVER OVERFLOW

AT JCT. OF IA. 58, Black Hawk, IA

Built 1995 Load: 34.4 t ADT: 8,400

MARQUIS RD W

Good

Over: STREAM

90-13-04-01, Black Hawk, IA

Built 2012 Load: 34.5 t ADT: 20

RAMP J (SB)

Good

Over: IA 57

AT JCT. OF IA 57, Black Hawk, IA

Built 1995 Load: 34.5 t ADT: 3,320

DUNKERTON RD

Good

Over: US 218

At Jct. Dunkerton Rd., Black Hawk, IA

Built 1995 Load: 34.5 t ADT: 599

E MARQUIS RD

Good

Over: PRINCIPAL

90-13-01-01, Black Hawk, IA

Built 2011 Load: 34.6 t ADT: 70

NEWELL ST

Good

Over: BLOWERS CREEK

CITY BRIDGE NO. 14, Black Hawk, IA

Built 1978 Load: 34.7 t ADT: 2,186

FOX RD

Good

Over: TRIB TO SPRING CREEK

88-11-23-01-10, Black Hawk, IA

Built 2000 Load: 34.7 t ADT: 49

E AIRLINE HWY

Good

Over: TRIB TO ELK RUN CREEK

89-12-11-01-10, Black Hawk, IA

Built 2000 Load: 34.7 t ADT: 15

W 27TH ST

Good

Over: TRIB TO BEAVER CREEK

89-14-19-01-10, Black Hawk, IA

Built 1994 Load: 34.7 t ADT: 854

VIKING RD

Good

Over: STREAM

000000000, Black Hawk, IA

Built 1990 Load: 34.7 t ADT: 7,193

N ELK RUN RD

Good

Over: TRIB TO ELK RUN CREEK

89-12-03-02-10, Black Hawk, IA

Built 1974 Load: 35.0 t ADT: 1,463

V49(RAYMOND RD)

Good

Over: I-380

AT JCT. S.R. V49, Black Hawk, IA

Built 1980 Load: 35.2 t ADT: 3,830

BRANDON RD

Good

Over: WOLF CREEK

87-11-19-04-10, Black Hawk, IA

Built 2012 Load: 35.3 t ADT: 1,542

RAMP J(SB)US218

Good

Over: IA 58

0.1 MI. N OF JCT. IA. #57, Black Hawk, IA

Built 1995 Load: 35.4 t ADT: 3,320

BARCLAY RD

Good

Over: POYNER CREEK

89-11-17-03-10, Black Hawk, IA

Built 1987 Load: 35.9 t ADT: 59

NEWELL ST

Good

Over: CAMP CREEK

89-11-23-01-10, Black Hawk, IA

Built 1988 Load: 35.9 t ADT: 44

RAMP B (EB)

Good

Over: CEDAR RIVER OVERFLOW

At Jct. U.S. 218 & IA 57, Black Hawk, IA

Built 1995 Load: 36.1 t ADT: 3,400

NB US 218

Good

Over: SINK CREEK

.7 mi S of jct US 20/I380, Black Hawk, IA

Built 1983 Load: 36.2 t ADT: 6,050

OSAGE RD

Good

Over: SPRING CREEK

89-11-36-01-10, Black Hawk, IA

Built 1985 Load: 36.3 t ADT: 648

US 218 SB

Good

Over: FLETCHER AVE

0.8 mi. N of Jct U.S. 63, Black Hawk, IA

Built 1991 Load: 36.3 t ADT: 11,100

W EAGLE ROAD

Good

Over: MILLER CREEK

87-13-20-01-10, Black Hawk, IA

Built 1988 Load: 36.4 t ADT: 471

SB US 218

Good

Over: LINCOLN ST & OVERFLO

0.3 Mi. N of Jct. IA 57, Black Hawk, IA

Built 1995 Load: 36.4 t ADT: 8,850

GILBERTVILLE RD

Good

Over: TRIB TO CEDAR RIVER

88-12-09-04-10, Black Hawk, IA

Built 1988 Load: 36.5 t ADT: 1,206

NB I-380

Good

Over: INDIAN CREEK

2.1 MI. S OF JCT. 20, Black Hawk, IA

Built 1984 Load: 36.6 t ADT: 8,450

NB US 218

Good

Over: NB US 63

3.6 mi. N of US 20, Black Hawk, IA

Built 1991 Load: 36.6 t ADT: 10,800

W CONGER ST

Good

Over: CEDAR RIVER

CITY BRIDGE NO. 12, Black Hawk, IA

Built 1977 Load: 36.7 t ADT: 10,190

US 218 SB

Good

Over: SB US 63

At jct. U.S. #63, Black Hawk, IA

Built 1991 Load: 36.7 t ADT: 11,250

CEDAR HEIGHTS DR

Good

Over: DRAINAGE

000000000, Black Hawk, IA

Built 1983 Load: 36.9 t ADT: 10,200

KATOSKI DR

Good

Over: DRAINAGE

CITY BRIDGE NO. 9, Black Hawk, IA

Built 1986 Load: 36.9 t ADT: 749

SB I-380

Good

Over: INDIAN CREEK

2.1 MI. S OF JCT. 20, Black Hawk, IA

Built 1984 Load: 36.9 t ADT: 8,450

E REINBECK RD

Good

Over: MUD CREEK

87-12-29-01-10, Black Hawk, IA

Built 1983 Load: 37.1 t ADT: 11

NB US 218

Good

Over: OVER CC & P RR

0.5 mi. N of Jct. IA 57, Black Hawk, IA

Built 1995 Load: 37.1 t ADT: 8,850

HAMMOND AVE

Good

Over: SMALL STREAM

CITY CULVERT NO. 50C, Black Hawk, IA

Built 1991 Load: 37.2 t ADT: 6,813

US 218 NB

Good

Over: SB US 63

At jct. U.S. #63, Black Hawk, IA

Built 1991 Load: 37.2 t ADT: 11,250

COTTER RD

Good

Over: TRIB TO MILLER CREEK

87-12-04-02-20, Black Hawk, IA

Built 2019 Load: 37.3 t ADT: 59

COTTER RD

Good

Over: MUD CREEK

87-12-21-02-10, Black Hawk, IA

Built 2013 Load: 37.3 t ADT: 5

HESS RD

Good

Over: TRIB TO MILLER CREEK

87-13-01-02-10, Black Hawk, IA

Built 2020 Load: 37.3 t ADT: 29

ANSBOROUGH AVE

Good

Over: TRIB TO MILLER CREEK

87-13-09-02-10, Black Hawk, IA

Built 2010 Load: 37.3 t ADT: 15

E QUARRY RD

Good

Over: TRIB TO MILLER CREEK

87-13-14-01-10, Black Hawk, IA

Built 2021 Load: 37.3 t ADT: 39

HAMMOND AVE

Good

Over: TRIB TO MILLER CREEK

87-13-14-02-10, Black Hawk, IA

Built 2021 Load: 37.3 t ADT: 15

Read our methodology - how this data is sourced, computed, and verified.

Related

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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.