Total bridges
296
Public highway bridges in Story County
County profile · official public datasets
Story County, IA
296 public highway bridges tracked in the FHWA National Bridge Inventory: 33.1% rated Good, 53% Fair, 13.9% Poor.
- 296
- Public bridges
- 33.1%
- Good condition
- 13.9%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Story County pairs a better-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.
- Top 30%
- lowest Poor share in state
- 13.9%
- Poor-condition share
- 296
- public highway bridges
- 1968
- 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.
Story County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Story County ranks #30 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 13.9%). Story County, Iowa contains 296 public highway bridges. Roughly 33.1% are rated “Good,” 53% “Fair,” and 13.9% “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
33.1%
98 of 296 rated 7-9
Fair condition
53%
157 of 296 rated 5-6
Poor condition
13.9%
41 of 296 rated 4 or below
In-state Poor-share rank
#30 of 99
Among Iowa counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 296 NBI-tracked bridges by lowest applicable component rating.
Good 33.1% (98)
Fair 53% (157)
Poor 13.9% (41)
Story County's Poor-condition bridges carry 4,593 vehicle crossings a day
That is 0.5% of the county's reported daily bridge traffic on 13.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 112 crossings a day against 3,682 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 296 of 296 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
63.9% of Story County's bridges have passed the 50-year mark
189 of the 296 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 33.1% 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 22.4% of the county's Poor-condition bridge traffic
E15/115TH ST over LONG DICK CREEK, built 1964, carries 1,028 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 41-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 4,593 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Story County's bridges were built
296 bridges with a recorded construction year, grouped by decade
- pre-1900 1
Built before 1900
1 bridges
- 1900s 14
1900–1909
14 bridges
- 1910s 17
1910–1919
17 bridges
- 1920s 10
1920–1929
10 bridges
- 1930s 15
1930–1939
15 bridges
- 1940s 9
1940–1949
9 bridges
- 1950s 26
1950–1959
26 bridges
- 1960s
1960–1969
71 bridges
- 1970s
1970–1979
37 bridges
- 1980s 18
1980–1989
18 bridges
- 1990s 16
1990–1999
16 bridges
- 2000s 19
2000–2009
19 bridges
- 2010s
2010–2019
34 bridges
- 2020s 9
2020–2029
9 bridges
What this shows Construction peaked in the 1960s, when 71 of the county's bridges still in the inventory were built, which is 24% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1968, 11 years older than the Iowa average of 1979.
How Story County compares with Iowa's closest counties by inventory size
The 5 Iowa counties nearest Story County in number of bridges, with their condition splits. Its 13.9% Poor share is the 4th-lowest of these 6. Its average build year of 1968 against a peer-group mean of 1980 is 12 years older.
Showing the 5 closest of 98 Iowa counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Cedar County | 301 | 42.9% | 37.5% | 19.6% | 1983 |
| Crawford County | 301 | 42.5% | 48.5% | 9% | 1982 |
| Story County (this page) | 296 | 33.1% | 53% | 13.9% | 1968 |
| Cass County | 295 | 25.4% | 41% | 33.6% | 1976 |
| Delaware County | 293 | 39.2% | 53.9% | 6.8% | 1981 |
| Scott County | 291 | 34.7% | 55% | 10.3% | 1980 |
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 Story 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 Story County, both outside Iowa so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IA (296 bridges here).
- Marion County, IL · 296 bridges
- Vigo County, IN · 296 bridges
- Guadalupe County, TX · 296 bridges
- Clark County, WI · 296 bridges
Similar average build year
Nearest mean year-built outside IA (1968 here).
- Montgomery County, PA · avg 1968 · 828 bridges
- San Joaquin County, CA · avg 1968 · 644 bridges
- Providence County, RI · avg 1968 · 476 bridges
- Imperial County, CA · avg 1968 · 444 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (157)
170TH ST
FairOver: SKUNK RIVER
084230703, Story, IA
Built 1939 Load: 28.1 t ADT: 139
R38/500TH AVE
FairOver: ONION CREEK
084243002, Story, IA
Built 1970 Load: 28.1 t ADT: 2,404
SB I-35
FairOver: BEAR CREEK
3.3 MILES S OF JCT SR E18, Story, IA
Built 1967 Load: 28.8 t ADT: 15,250
150TH ST
FairOver: BEAR CREEK
085233205, Story, IA
Built 1985 Load: 28.8 t ADT: 50
STATE AVE
FairOver: US 30
1.0 mile East of SR R38, Story, IA
Built 1971 Load: 28.9 t ADT: 2,229
NB I-35
FairOver: BEAR CREEK
3.3 MILES SOUTH OF SR E18, Story, IA
Built 1967 Load: 29.2 t ADT: 15,250
190TH ST/E29
FairOver: DYE CREEK
084212001, Story, IA
Built 1973 Load: 29.4 t ADT: 669
650TH AVE
FairOver: EAST BR INDIAN CREEK
083223404, Story, IA
Built 1976 Load: 30.2 t ADT: 1,228
E AVE
FairOver: W BR INDIAN CREEK
000000000, Story, IA
Built 1967 Load: 31.5 t ADT: 555
IA 210
FairOver: CALAMUS CREEK
0.9 MILE W OF JCT SR S27, Story, IA
Built 1954 Load: 31.5 t ADT: 1,920
SB I-35
FairOver: LONG DICK CREEK
0.5 MILES N OF SR E18, Story, IA
Built 1967 Load: 32.2 t ADT: 14,850
WB US 30
FairOver: US 69
AT US 69 JUNCTION, Story, IA
Built 1963 Load: 32.7 t ADT: 9,850
US 69
FairOver: WALNUT CREEK
0.2 MILE N OF JCT SR E57, Story, IA
Built 1913 Load: 32.7 t ADT: 6,700
6TH ST
FairOver: WEST INDIAN CREEK
000000000, Story, IA
Built 1964 Load: 32.7 t ADT: 1,850
I-35
FairOver: BALLARD CREEK
1.9 MILES N OF JCT IA 210, Story, IA
Built 1964 Load: 32.7 t ADT: 46,600
I-35
FairOver: WALNUT CREEK
4.2 MILES N OF JCT IA 210, Story, IA
Built 1964 Load: 32.7 t ADT: 46,600
E29 190TH ST
FairOver: I-35
4.9 MILES N OF JCT. US 30, Story, IA
Built 1966 Load: 32.7 t ADT: 1,845
I 35 NB
FairOver: US 30
AT JUNCTION WITH US 30, Story, IA
Built 1964 Load: 32.8 t ADT: 14,400
EB US 30
FairOver: US 69 & BIKE PATH
AT JCT. OF US 69, Story, IA
Built 1963 Load: 32.9 t ADT: 9,850
I 35 SB
FairOver: US 30
AT JUNCTION WITH US 30, Story, IA
Built 1964 Load: 33.1 t ADT: 15,950
R38/500TH AVE
FairOver: IOWAY CREEK
084240702, Story, IA
Built 1976 Load: 33.2 t ADT: 1,496
SR R38
FairOver: US 30
AT JUNCTION SR R38 NB, Story, IA
Built 1971 Load: 33.5 t ADT: 2,493
IA 210
FairOver: I-35
AT JCT. I-35, Story, IA
Built 1964 Load: 33.7 t ADT: 4,220
310TH ST
FairOver: ROCK CREEK
082222301, Story, IA
Built 1988 Load: 33.7 t ADT: 40
180TH ST/E29
FairOver: RICHLAND 81 OPEN DITCH
084222201, Story, IA
Built 2009 Load: 33.7 t ADT: 1,028
170TH ST
FairOver: SMALL
084240701, Story, IA
Built 2006 Load: 33.9 t ADT: 1,137
EB US 30
FairOver: OVER UP RR
0.1 MILE W OF JCT SR S14, Story, IA
Built 1963 Load: 34.7 t ADT: 7,900
MINNESOTA AVE
FairOver: OVER UPRR
A66600500, Story, IA
Built 1980 Load: 34.7 t ADT: 488
LINCOLN WAY
FairOver: I-35
1.0 MI NORTH OF JCT US 30, Story, IA
Built 1966 Load: 34.9 t ADT: 5,642
670TH AVE
FairOver: EAST INDIAN CREEK
084221202, Story, IA
Built 1915 Load: 35.1 t ADT: 26
SB I-35
FairOver: BIKE PATH
1.1 MI. N OF JCT. IA 210, Story, IA
Built 1964 Load: 35.2 t ADT: 23,300
E15 115TH ST
FairOver: I-35
AT JUNCTION SR E15, Story, IA
Built 1965 Load: 35.3 t ADT: 4,079
690TH AVE
FairOver: DYE CREEK
083210502, Story, IA
Built 1998 Load: 35.5 t ADT: 45
WB US 30
FairOver: OVER UP RR
0.1 MILE W OF JCT SR S14, Story, IA
Built 1963 Load: 35.6 t ADT: 7,900
SB I-35
FairOver: OVER UP RR
1.4 MI. N OF JCT. US 30, Story, IA
Built 1966 Load: 35.9 t ADT: 18,000
WEST T AVE
FairOver: WEST BR INDIAN CREEK
083230103, Story, IA
Built 1997 Load: 36.2 t ADT: 139
640TH AVE
FairOver: EAST BR INDIAN CREEK
1.3 miles S of E18, Story, IA
Built 2015 Load: 36.3 t ADT: 15
I-35 NB
FairOver: 13TH ST
1.8 MILES N OF JCT US 30, Story, IA
Built 1966 Load: 36.4 t ADT: 13,200
R70/580TH AVE
FairOver: SKUNK RIVER
082230904, Story, IA
Built 1989 Load: 36.6 t ADT: 818
NB I-35
FairOver: BIKE PATH
1.1 MILES N OF JCT IA 210, Story, IA
Built 1964 Load: 36.8 t ADT: 23,300
ARRASMITH TRL
FairOver: D D
084242308, Story, IA
Built 1996 Load: 37.5 t ADT: 319
E26/C.S. RD
FairOver: IOWAY CREEK
084242005, Story, IA
Built 1982 Load: 38.5 t ADT: 3,640
NB I-35
FairOver: OVER UP RR
1.5 MILES N OF JCT US 30, Story, IA
Built 1966 Load: 38.8 t ADT: 18,000
E41 LINCOLN HWY
FairOver: DYE CREEK
083210701, Story, IA
Built 2001 Load: 39.8 t ADT: 1,048
I 35 SB
FairOver: 13TH ST
1.9 MILES N OF JCT US 30, Story, IA
Built 1966 Load: 40.8 t ADT: 13,200
S DAYTON AVE
FairOver: US 30
0.8 MILE WEST OF I-35, Story, IA
Built 1994 Load: 40.8 t ADT: 5,164
200TH ST
FairOver: DD 81
084222603, Story, IA
Built 2000 Load: 41.5 t ADT: 40
R 38/510TH AVE
FairOver: WALNUT CREEK
083242902, Story, IA
Built 2010 Load: 41.6 t ADT: 4,647
6TH ST
FairOver: OVER UPRR
A19000665, Story, IA
Built 1966 Load: 42.2 t ADT: 3,863
E18/130TH ST
FairOver: MIDDLE MINERVA CREEK
085211901, Story, IA
Built 1973 Load: 42.9 t ADT: 638
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.