County profile · official public datasets

Arapahoe County, CO

391 public highway bridges tracked in the FHWA National Bridge Inventory: 26.1% rated Good, 66.8% Fair, 7.2% Poor.

391
Public bridges: 26.1%
Good condition: 7.2%
Poor condition

The verdict

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

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

52nd
of 64 on Poor share: 7.2%
Poor-condition share: 391
public highway bridges: 1984
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.

Arapahoe County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Arapahoe County ranks #52 of 64 Colorado counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 7.2%). Arapahoe County, Colorado contains 391 public highway bridges. Roughly 26.1% are rated “Good,” 66.8% “Fair,” and 7.2% “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

391

Public highway bridges in Arapahoe County

Good condition

26.1%

102 of 391 rated 7-9

Fair condition

66.8%

261 of 391 rated 5-6

Poor condition

7.2%

28 of 391 rated 4 or below

In-state Poor-share rank

#52 of 64

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

Condition distribution

Share of 391 NBI-tracked bridges by lowest applicable component rating.

Good

26.1% (102)

Fair

66.8% (261)

Poor

7.2% (28)

Arapahoe County's Poor-condition bridges carry 313,856 vehicle crossings a day

That is 4.1% of the county's reported daily bridge traffic on 7.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 11,209 crossings a day against 18,155 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 391 of 391 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

33.8% of Arapahoe County's bridges have passed the 50-year mark

132 of the 391 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 26.1% 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 14.7% of the county's Poor-condition bridge traffic

US 285 ML over LITTLE DRY CREEK, built 1955, carries 46,000 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 28-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 313,856 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1930s

11
1950s

16
1960s

85
1970s

41
1980s

73
1990s

68
2000s

65
2010s

23
2020s

9

What this shows Construction peaked in the 1960s, when 85 of the county's bridges still in the inventory were built, which is 21.7% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1984) matches the Colorado average (1982).

How Arapahoe County compares with Colorado's closest counties by inventory size

The 5 Colorado counties nearest Arapahoe County in number of bridges, with their condition splits. Its 7.2% Poor share is the 6th-lowest of these 6. Its average build year of 1984 against a peer-group mean of 1983 is in line with the group.

Showing the 5 closest of 63 Colorado counties eligible for comparison.

Bridge inventory size and condition shares for Arapahoe County and the 5 Colorado counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Jefferson County	464	33.8%	59.9%	6.3%	1984
Denver County	458	41.9%	56.3%	1.7%	1991
Arapahoe County (this page)	391	26.1%	66.8%	7.2%	1984
Mesa County	319	35.1%	63.3%	1.6%	1981
Boulder County	311	34.4%	63.3%	2.3%	1987
Pueblo County	264	29.5%	65.9%	4.5%	1973

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

Similar inventory size

Nearest county inventories outside CO (391 bridges here).

Lee County, FL · 391 bridges
Kingman County, KS · 391 bridges
Wayne County, OH · 391 bridges
DeKalb County, GA · 392 bridges

Similar average build year

Nearest mean year-built outside CO (1984 here).

Hennepin County, MN · avg 1984 · 936 bridges
Duval County, FL · avg 1984 · 831 bridges
Bell County, TX · avg 1984 · 660 bridges
Steuben County, NY · avg 1984 · 627 bridges

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

All 391 Good 102 Fair 261 Poor 28

Fair-condition bridges (261)

Sort:

Arapahoe County Bridge Snapshot

Condition distribution

Arapahoe County's Poor-condition bridges carry 313,856 vehicle crossings a day

33.8% of Arapahoe County's bridges have passed the 50-year mark

One structure carries 14.7% of the county's Poor-condition bridge traffic

How Arapahoe County compares with Colorado's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Fair-condition bridges (261)

TOWER ROAD

COUNTY ROAD 30

SH 83 RAMP TO I225

KENTUCKY AVE

ALAMEDA AVE

PRINCE STREET

SB BUCKLEY ROAD

LOWELL BLVD

HAVANA ST/SH 30 ML

QUINCY AVE

I 25 ML

E-470 NB

SH 88 (BELLEVIEW)

SH 83 ML

I 70 ML

COUNTY ROAD 6

EXPOSITION AVE

CHAMBERS ROAD

EB ALAMEDA AVE

ALAMEDA AVENUE

S PLATTE RIVER DR.

HAMPDEN AVENUE

BROADWAY

ASPEN STREET

COUNTY ROAD 129

COUNTY ROAD 18

E. ILIFF AVE.

COUNTY ROAD 30

COUNTY ROAD 30

COUNTY ROAD 30

COUNTY ROAD 30

COUNTY ROAD 30

HARVARD AVE

COUNTY ROAD 38

JOLIET ST

INVERNESS DR EAST

EASTER AVE

INVERNESS DR E.

BLACKHAWK ST

7TH PLACE

DILLON WAY

1ST AVENUE

WB MISSISSIPPI AVE

EB MISSISSIPPI AVE

GUN CLUB RD

JEWELL AVENUE

MEXICO AVE

JEWELL AVENUE

FLANDERS STREET

HAMPDEN AVE

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