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.
All bridges (296)
NB I-35
FairOver: LONG DICK CREEK
0.5 MILES N OF SR E18, Story, IA
Built 1967 Load: 43.1 t ADT: 14,850
W RIVERSIDE RD
FairOver: SKUNK RIVER
084242207, Story, IA
Built 1989 Load: 43.7 t ADT: 3,301
WB US 30
FairOver: UNIVERISTY BLVD
1.5 MILES W OF JCT US 69, Story, IA
Built 1971 Load: 45.4 t ADT: 8,900
LINCOLN WAY
FairOver: OVER UP RR
000000000, Story, IA
Built 1984 Load: 46.0 t ADT: 5,356
W 4TH ST
FairOver: WEST BR INDIAN CREEK
000000000, Story, IA
Built 1998 Load: 52.3 t ADT: 1,119
R38 500TH AVE
FairOver: CLEAR CREEK
084243106, Story, IA
Built 1969 Load: 59.2 t ADT: 2,712
R70/580TH AVE
FairOver: SMALL STREAM
083233302, Story, IA
Built 1987 Load: 99.9 t ADT: 818
290TH ST
GoodOver: I-35
4.0 MILES N OF JCT IA 210, Story, IA
Built 1964 Load: 14.9 t ADT: 139
150TH ST
GoodOver: KEIGLEY BRANCH
085243501, Story, IA
Built 1977 Load: 16.3 t ADT: 100
STANGE RD(ISU)
GoodOver: IOWAY CREEK (STANGE)
0.1 MILE N OF SR 13TH ST, Story, IA
Built 1965 Load: 16.7 t ADT: 15,397
US 30
GoodOver: RICHARDS CREEK
0.1 MILE EAST OF JCT I-35, Story, IA
Built 1963 Load: 18.1 t ADT: 14,000
DUNN STREET
GoodOver: DRAINAGE DITCH #70
Dunn Street, Story, IA
Built 1969 Load: 18.1 t ADT: 170
S 16TH ST (ISU)
GoodOver: WORRELL CREEK
0.1 MILE E OF UNIV BLVD, Story, IA
Built 1974 Load: 20.4 t ADT: 9,754
140TH ST
GoodOver: KEIGLEY BRANCH
085242701, Story, IA
Built 1977 Load: 20.9 t ADT: 34
500TH AVE
GoodOver: US 30
1.1 MI. W of SR. R-38, Story, IA
Built 1971 Load: 22.7 t ADT: 170
13TH ST
GoodOver: IOWAY CREEK (13TH)
City of Ames, Story, IA
Built 1974 Load: 24.1 t ADT: 9,563
150TH ST
GoodOver: I-35
2.1 MILES SOUTH OF SR E18, Story, IA
Built 1967 Load: 24.6 t ADT: 71
E23 170TH ST
GoodOver: I-35
2.1 MILES NORTH OF SR E29, Story, IA
Built 1967 Load: 25.3 t ADT: 139
R38/S DAKOTA AV
GoodOver: WORRELL CREEK
083241714, Story, IA
Built 2010 Load: 25.3 t ADT: 4,647
US 65
GoodOver: STREAM
2.4 MILES N OF JCT SR E18, Story, IA
Built 1990 Load: 27.5 t ADT: 1,440
BEACH ROAD
GoodOver: COLLEGE CREEK
0.1 mi. N of Lincolnway, Story, IA
Built 1973 Load: 29.0 t ADT: 4,878
US 65
GoodOver: DRAINAGE DITCH
2.9 MILES N OF JCT US 30, Story, IA
Built 1987 Load: 30.1 t ADT: 2,110
US 69
GoodOver: IOWAY CREEK
0.6 mi. N of Jct. US 30, Story, IA
Built 1924 Load: 30.3 t ADT: 24,600
595TH AVE
GoodOver: SKUNK RIVER
082232203, Story, IA
Built 2002 Load: 31.1 t ADT: 290
US 69
GoodOver: KEIGLEY BRANCH
1.1 Mi. S of SR E18, Story, IA
Built 2016 Load: 32.4 t ADT: 4,850
E18 W MAPLE ST
GoodOver: BEAR CREEK
E18 ov Bear Creek, Story, IA
Built 2021 Load: 32.4 t ADT: 2,533
I 35 NB
GoodOver: SOUTH SKUNK RIVER
2.6 MILES S OF JCT US 30, Story, IA
Built 2018 Load: 32.4 t ADT: 23,300
I 35 SB
GoodOver: SOUTH SKUNK RIVER
2.6 MI. S OF Jct. U.S. 30, Story, IA
Built 2017 Load: 32.4 t ADT: 23,300
E57 260TH ST
GoodOver: I 35
2.0 MILES S OF JCT 30/35, Story, IA
Built 2017 Load: 32.4 t ADT: 50
I35 NB TO US 30 EB
GoodOver: DRAINAGE DITCH
AT JCT. US 30, Story, IA
Built 2017 Load: 32.4 t ADT: 1,420
290TH ST
GoodOver: DRAINAGE DITCH
0.4 Mi E of US Hwy 69, Story, IA
Built 2019 Load: 32.4 t ADT: 120
11TH ST
GoodOver: US 30
0.9 MILE E OF JCT SR S14, Story, IA
Built 1995 Load: 32.6 t ADT: 1,997
HYLAND AVE
GoodOver: CLEAR CREEK
A69200620, Story, IA
Built 1984 Load: 32.7 t ADT: 7,253
BROAD ST
GoodOver: SKUNK RIVER
085241201, Story, IA
Built 1996 Load: 32.7 t ADT: 5,834
US 30
GoodOver: WORRELL CREEK
2.0 mi. W of Jct. U.S. 69, Story, IA
Built 1971 Load: 32.7 t ADT: 23,700
US 30
GoodOver: DYE CREEK
2.1 MILES W OF JCT US 65, Story, IA
Built 1963 Load: 32.7 t ADT: 9,400
663RD AVE
GoodOver: SMALL STREAM
082222608, Story, IA
Built 2011 Load: 32.7 t ADT: 71
IA 210
GoodOver: ROCK CREEK
1.2 MILE WEST OF SR S28, Story, IA
Built 1974 Load: 32.7 t ADT: 1,400
R70/580TH AVE
GoodOver: BALLARD CREEK
082231604, Story, IA
Built 1989 Load: 32.7 t ADT: 818
210TH ST
GoodOver: DYE CREEK
0.15 mi E. of US Hwy 65, Story, IA
Built 2019 Load: 32.7 t ADT: 26
590TH AVE
GoodOver: OVRFLW OF MILFORD 13
0.33 Mi. S of NW Co., Story, IA
Built 2017 Load: 33.7 t ADT: 45
E29/190TH ST
GoodOver: WEST BR INDIAN CREEK
084232301, Story, IA
Built 2005 Load: 33.7 t ADT: 1,217
690TH AVE
GoodOver: MIDDLE MINERVA CREEK
0.3 Mi S E18, Story, IA
Built 2020 Load: 33.7 t ADT: 11
550TH AVE
GoodOver: HAMILTON-STORY 1 OPEN DD
1.5 miles S of E18, Story, IA
Built 2015 Load: 33.7 t ADT: 80
I 35
GoodOver: SOUTH SKUNK RVR OVERFLOW
1.9 mi. S of US 30, Story, IA
Built 2017 Load: 33.7 t ADT: 46,600
6TH ST
GoodOver: IOWAY CREEK
Brookside Park, Story, IA
Built 2016 Load: 34.0 t ADT: 3,863
E63 305TH ST
GoodOver: CALAMUS CREEK
0.3 Mi E S14, Story, IA
Built 2016 Load: 34.0 t ADT: 90
N DAKOTA AVE
GoodOver: ONION CREEK
084243204, Story, IA
Built 2014 Load: 34.7 t ADT: 1,197
730TH AVE
GoodOver: MIDDLE MINERVA CREEK
085212502, Story, IA
Built 1983 Load: 34.9 t ADT: 26
US 65
GoodOver: DYE CREEK
1.8 MI. N OF US 30, Story, IA
Built 1979 Load: 35.3 t ADT: 2,110
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.