County profile · official public datasets

Adams County, CO

535 public highway bridges tracked in the FHWA National Bridge Inventory: 43.9% rated Good, 49.2% Fair, 6.9% Poor.

535
Public bridges: 43.9%
Good condition: 6.9%
Poor condition

The verdict

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

Adams County pairs a higher-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.

49th
of 64 on Poor share: 6.9%
Poor-condition share: 535
public highway bridges: 1990
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.

Adams County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Adams County ranks #49 of 64 Colorado counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.9%). Adams County, Colorado contains 535 public highway bridges. Roughly 43.9% are rated “Good,” 49.2% “Fair,” and 6.9% “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.

Total bridges

535

Public highway bridges in Adams County

Good condition

43.9%

235 of 535 rated 7-9

Fair condition

49.2%

263 of 535 rated 5-6

Poor condition

6.9%

37 of 535 rated 4 or below

In-state Poor-share rank

#49 of 64

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

Condition distribution

Share of 535 NBI-tracked bridges by lowest applicable component rating.

Good

43.9% (235)

Fair

49.2% (263)

Poor

6.9% (37)

Adams County's Poor-condition bridges carry 578,957 vehicle crossings a day

That is 5.2% of the county's reported daily bridge traffic on 6.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 16,082 crossings a day against 21,840 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 531 of 535 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

21.3% of Adams County's bridges have passed the 50-year mark

114 of the 535 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 43.9% 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 8.4% of the county's Poor-condition bridge traffic

I 270 ML WBND over SOUTH PLATTE RIVER, built 1969, carries 48,500 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 37-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 578,957 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1930s

3
1940s

6
1950s

18
1960s

61
1970s

42
1980s

67
1990s

152
2000s

134
2010s

45
2020s

7

What this shows Construction peaked in the 1990s, when 152 of the county's bridges still in the inventory were built, which is 28.4% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year is 1990, 8 years newer than the Colorado average of 1982.

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

The 5 Colorado counties nearest Adams County in number of bridges, with their condition splits. Its 6.9% Poor share is the 5th-lowest of these 6. Its average build year of 1990 against a peer-group mean of 1986 is in line with the group.

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

Bridge inventory size and condition shares for Adams County and the 5 Colorado counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Weld County	614	36.8%	58.5%	4.7%	1986
Larimer County	559	49%	49%	2%	1987
Adams County (this page)	535	43.9%	49.2%	6.9%	1990
Jefferson County	464	33.8%	59.9%	6.3%	1984
Denver County	458	41.9%	56.3%	1.7%	1991
Arapahoe County	391	26.1%	66.8%	7.2%	1984

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

Similar inventory size

Nearest county inventories outside CO (535 bridges here).

Marathon County, WI · 530 bridges
Merced County, CA · 528 bridges
LaSalle County, IL · 528 bridges
Nueces County, TX · 528 bridges

Similar average build year

Nearest mean year-built outside CO (1990 here).

Maricopa County, AZ · avg 1990 · 2,847 bridges
Tarrant County, TX · avg 1990 · 2,617 bridges
Fairfax County, VA · avg 1990 · 751 bridges
Guilford County, NC · avg 1990 · 736 bridges

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

All 535 Good 235 Fair 263 Poor 37

Good-condition bridges (235)

Sort:

Adams County Bridge Snapshot

Condition distribution

Adams County's Poor-condition bridges carry 578,957 vehicle crossings a day

21.3% of Adams County's bridges have passed the 50-year mark

One structure carries 8.4% of the county's Poor-condition bridge traffic

How Adams 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

Good-condition bridges (235)

I 25 RAMP

SH 2 ML SBND

US 36 ML

I 76 ML WBND

I 76 ML EBND

US 36 EBND ML

US 36 ML

75TH AVE

72ND AVENUE

CLAUDE COURT

SH 128 ML/120TH AV

WOLF CREEK ROAD

E-470 NB

E-470 NB

E-470 SB

E-470 SB

US 36 ML

I 76 ML EBND

E-470 NB

I 76 ML WBND

I 76 ML

I 76 ML WBND

E-470 SB

I 76 ML WBND

I 76 ML WBND

I 76 ML EBND

I 76 EBND ML

E-470 SB

I76 EB RAMP TO I25

86TH AVENUE

86TH AVENUE

SB E470 RAMP-120TH

E-470 NB

E-470 NB

E-470 NB

E-470 SB

E-470 SB

BUCKLEY ROAD

SH 224 ML

112TH AVENUE

TOWER ROAD

E-470 NB

E-470 SB

SH 7 ML

CONVERSE ROAD

I 225 ML

E-470 SB

RAMP TO I 70 EBND

I 76 EBND ML

I 76 WBND ML

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