County profile · official public datasets

Riley County, KS

224 public highway bridges tracked in the FHWA National Bridge Inventory: 56.7% rated Good, 37.9% Fair, 5.4% Poor.

224
Public bridges: 56.7%
Good condition: 5.4%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

Riley County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

62nd
of 104 on Poor share: 5.4%
Poor-condition share: 224
public highway bridges: 1976
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.

Riley County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Riley County ranks #62 of 104 Kansas counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 5.4%). Riley County, Kansas contains 224 public highway bridges. Roughly 56.7% are rated “Good,” 37.9% “Fair,” and 5.4% “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

224

Public highway bridges in Riley County

Good condition

56.7%

127 of 224 rated 7-9

Fair condition

37.9%

85 of 224 rated 5-6

Poor condition

5.4%

12 of 224 rated 4 or below

In-state Poor-share rank

#62 of 104

Among Kansas counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 224 NBI-tracked bridges by lowest applicable component rating.

Good

56.7% (127)

Fair

37.9% (85)

Poor

5.4% (12)

Riley County's Poor-condition bridges carry 878 vehicle crossings a day

That is 0.2% of the county's reported daily bridge traffic on 5.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 73 crossings a day against 2,583 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 224 of 224 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

45.1% of Riley County's bridges have passed the 50-year mark

101 of the 224 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 56.7% 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 40% of the county's Poor-condition bridge traffic

RS 1092 R.4-32.0F over MCDOWELL CREEK, built 1980, carries 351 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 12-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 878 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

4
1920s

21
1930s

14
1940s

14
1950s

15
1960s

28
1970s

18
1980s

23
1990s

15
2000s

24
2010s

37
2020s

11

What this shows Construction peaked in the 2010s, when 37 of the county's bridges still in the inventory were built, which is 16.5% of those with a recorded year. That cohort is now 5 to 14 years old in the 2024 inventory. Its average build year (1976) matches the Kansas average (1972).

How Riley County compares with Kansas's closest counties by inventory size

The 5 Kansas counties nearest Riley County in number of bridges, with their condition splits. Its 5.4% Poor share is the 3rd-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1963 is 13 years newer.

Showing the 5 closest of 103 Kansas counties eligible for comparison.

Bridge inventory size and condition shares for Riley County and the 5 Kansas counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Greenwood County	235	24.7%	54%	21.3%	1957
Clay County	231	51.9%	42.9%	5.2%	1970
Allen County	227	45.4%	43.6%	11%	1959
Lincoln County	225	33.3%	56.4%	10.2%	1957
Riley County (this page)	224	56.7%	37.9%	5.4%	1976
Ford County	223	50.2%	49.8%	0%	1972

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 Riley 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 Riley County, both outside Kansas so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside KS (224 bridges here).

Conecuh County, AL · 224 bridges
Sac County, IA · 224 bridges
Clarke County, MS · 224 bridges
Sullivan County, MO · 224 bridges

Similar average build year

Nearest mean year-built outside KS (1976 here).

Marion County, IN · avg 1976 · 958 bridges
Mohave County, AZ · avg 1976 · 641 bridges
Comanche County, OK · avg 1976 · 593 bridges
Prince George's County, MD · avg 1976 · 576 bridges

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

All 224 Good 127 Fair 85 Poor 12

Good-condition bridges (127)

Sort:

Riley County Bridge Snapshot

Condition distribution

Riley County's Poor-condition bridges carry 878 vehicle crossings a day

45.1% of Riley County's bridges have passed the 50-year mark

One structure carries 40% of the county's Poor-condition bridge traffic

How Riley County compares with Kansas's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Good-condition bridges (127)

EB K18 HWY

LOCAL G.0-6.2T

RS 128 F.5-5.9F

EB K-18 HWY

RS 130 B.4-17.5F

US77 HWY

LOCAL P.6-31.0T

EB K-18

WB K-18

W 56TH AVE

RS 128 E.2-5.6F

US-24 HWY EB

K113 HWY

K113 HWY SB

LOCAL J.6-4.1T

US77 HWY

SCENIC DRIVE

K-18 / K-177 HWY

K-113 HWY

MILLER PKWY/DAVIS

Y.3-34.0T Min Spr

12TH ST OVER K-18

PARALLEL I.7-0.0T

RS 1092 Q.8-33.5F

MINOR I.0-0.8T

K18 & SKYWAY DR

K-113 HWY NB

RS 1925 P.1-24.5F

LOCAL D.5-9.1T

LOCAL CC.0-27.0C

LOCAL O.7-0.5T

AIRPORT ROAD

K-18 HWY WB

K-18 HWY EB

PICKERING Y.3-35.0

CIMARRON TRAIL

COLLEGE AVE T.5-24

LOCAL U.6-27.2C

LOCAL H.0-5.5

K-114 HWY

Local J.0-16.2

(URBAN) V.0-24.2F

JERUSALE I.7-1.9F

RS 1925 M.6-23.2F

EB K18 OVER KS RIV

SKYWAY DR.

WB K18 HWY

K18 HWY WB

MINOR P.6-25.7

LOCAL J.3-2.7T

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