County profile · official public datasets

Navajo County, AZ

277 public highway bridges tracked in the FHWA National Bridge Inventory: 52.7% rated Good, 45.1% Fair, 2.2% Poor.

277
Public bridges: 52.7%
Good condition: 2.2%
Poor condition

The verdict

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

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

9th
of 15 on Poor share: 2.2%
Poor-condition share: 277
public highway bridges: 1972
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.

Navajo County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Navajo County ranks #9 of 15 Arizona counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 2.2%). Navajo County, Arizona contains 277 public highway bridges. Roughly 52.7% are rated “Good,” 45.1% “Fair,” and 2.2% “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

277

Public highway bridges in Navajo County

Good condition

52.7%

146 of 277 rated 7-9

Fair condition

45.1%

125 of 277 rated 5-6

Poor condition

2.2%

6 of 277 rated 4 or below

In-state Poor-share rank

#9 of 15

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

Condition distribution

Share of 277 NBI-tracked bridges by lowest applicable component rating.

Good

52.7% (146)

Fair

45.1% (125)

Poor

2.2% (6)

Navajo County's Poor-condition bridges carry 27,920 vehicle crossings a day

That is 1.9% of the county's reported daily bridge traffic on 2.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 4,653 crossings a day against 5,999 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 277 of 277 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

55.2% of Navajo County's bridges have passed the 50-year mark

153 of the 277 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 52.7% 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 75.7% of the county's Poor-condition bridge traffic

I-40 WB over SB 40, built 1969, carries 21,131 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 6-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 27,920 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

1
1910s

3
1920s

1
1930s

21
1940s

12
1950s

23
1960s

58
1970s

68
1980s

40
1990s

15
2000s

22
2010s

11
2020s

2

What this shows Construction peaked in the 1970s, when 68 of the county's bridges still in the inventory were built, which is 24.5% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1972, 5 years older than the Arizona average of 1977.

How Navajo County compares with Arizona's closest counties by inventory size

The 5 Arizona counties nearest Navajo County in number of bridges, with their condition splits. Its 2.2% Poor share is the 2nd-lowest of these 6. Its average build year of 1972 against a peer-group mean of 1967 is 5 years newer.

Showing the 5 closest of 14 Arizona counties eligible for comparison.

Bridge inventory size and condition shares for Navajo County and the 5 Arizona counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
La Paz County	306	64.1%	32.4%	3.6%	1961
Navajo County (this page)	277	52.7%	45.1%	2.2%	1972
Yuma County	262	50.4%	47.7%	1.9%	1973
Apache County	259	48.3%	45.9%	5.8%	1973
Gila County	259	60.2%	37.5%	2.3%	1975
Graham County	179	44.1%	52%	3.9%	1954

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

Similar inventory size

Nearest county inventories outside AZ (277 bridges here).

Delaware County, IN · 277 bridges
Porter County, IN · 277 bridges
Shelby County, OH · 277 bridges
Florence County, SC · 277 bridges

Similar average build year

Nearest mean year-built outside AZ (1972 here).

Santa Clara County, CA · avg 1972 · 964 bridges
Madison County, AL · avg 1972 · 710 bridges
Kern County, CA · avg 1972 · 668 bridges
York County, PA · avg 1972 · 569 bridges

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

All 277 Good 146 Fair 125 Poor 6

All bridges (277)

Sort:

Navajo County Bridge Snapshot

Condition distribution

Navajo County's Poor-condition bridges carry 27,920 vehicle crossings a day

55.2% of Navajo County's bridges have passed the 50-year mark

One structure carries 75.7% of the county's Poor-condition bridge traffic

How Navajo County compares with Arizona's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

All bridges (277)

IRR BIA RT 551

IRR BIA RTE 1

I-40 EB

SR 277

US 163

SR 260

Lone Pine Dam Road

I-40 WB

W Mahoney St

I-40 EB

I-40 WB

Porter Mountain Rd

IRR BIA RTE 42

SR 77

I-40 EB

I-40 WB

I-40 EB

I-40 WB

I-40 EB

I-40 WB

Paper Mill Road

IRR BIA RTE 8066

I-40 EB

SR 99

SR 260

SR 260

I-40 WB

IRR SR 87

IRR SR 87

SR 77

IRR SR 87

US 160

US 180

I-40

IRR SR 264

SR 260

US 60

US 60

SR 77

SR 77

IRR SR 87

IRR SR 87

IRR SR 87

US 180

SR 260

IRR SR 264

I 40; EB WB & NFR

I 40; EB & WB

SR 260

US 60

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