County profile · official public datasets

San Juan County, UT

50 public highway bridges tracked in the FHWA National Bridge Inventory: 24% rated Good, 74% Fair, 2% Poor.

50
Public bridges: 24%
Good condition: 2%
Poor condition

The verdict

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

San Juan 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 48%
lowest Poor share in state: 2%
Poor-condition share: 50
public highway bridges: 1974
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.

San Juan County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, San Juan County ranks #14 of 29 Utah counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 2%). San Juan County, Utah contains 50 public highway bridges. Roughly 24% are rated “Good,” 74% “Fair,” and 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

Public highway bridges in San Juan County

Good condition

24%

12 of 50 rated 7-9

Fair condition

74%

37 of 50 rated 5-6

Poor condition

1 of 50 rated 4 or below

In-state Poor-share rank

#14 of 29

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

Condition distribution

Share of 50 NBI-tracked bridges by lowest applicable component rating.

Good

24% (12)

Fair

74% (37)

Poor

2% (1)

San Juan County's Poor-condition bridges carry 430 vehicle crossings a day

That is 0.6% of the county's reported daily bridge traffic on 2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 430 crossings a day against 1,636 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 50 of 50 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

60% of San Juan County's bridges have passed the 50-year mark

30 of the 50 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 24% 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 100% of the county's Poor-condition bridge traffic

SR-95 over COTTONWOOD WASH, built 1959, carries 430 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 1-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 430 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1940s

1
1950s

11
1960s

13
1970s

8
1980s

6
1990s

6
2000s

2
2010s

1
2020s

2

What this shows Construction peaked in the 1960s, when 13 of the county's bridges still in the inventory were built, which is 26% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1974, 10 years older than the Utah average of 1984.

How San Juan County compares with Utah's closest counties by inventory size

The 5 Utah counties nearest San Juan County in number of bridges, with their condition splits. Its 2% Poor share is the 3rd-lowest of these 6. Its average build year of 1974 against a peer-group mean of 1978 is in line with the group.

Showing the 5 closest of 28 Utah counties eligible for comparison.

Bridge inventory size and condition shares for San Juan County and the 5 Utah counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Juab County	60	8.3%	88.3%	3.3%	1980
Beaver County	53	17%	79.2%	3.8%	1977
Morgan County	53	0%	96.2%	3.8%	1967
Sanpete County	52	30.8%	69.2%	0%	1986
San Juan County (this page)	50	24%	74%	2%	1974
Tooele County	35	17.1%	82.9%	0%	1979

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 San Juan 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 San Juan County, both outside Utah so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside UT (50 bridges here).

Oglethorpe County, GA · 50 bridges
Randolph County, GA · 50 bridges
Putnam County, IL · 50 bridges
Simpson County, KY · 50 bridges

Similar average build year

Nearest mean year-built outside UT (1974 here).

Knox County, TN · avg 1974 · 588 bridges
Summit County, OH · avg 1974 · 563 bridges
Onondaga County, NY · avg 1974 · 472 bridges
Orange County, NY · avg 1974 · 472 bridges

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

All 50 Good 12 Fair 37 Poor 1

All bridges (50)

Sort:

San Juan County Bridge Snapshot

Condition distribution

San Juan County's Poor-condition bridges carry 430 vehicle crossings a day

60% of San Juan County's bridges have passed the 50-year mark

One structure carries 100% of the county's Poor-condition bridge traffic

How San Juan County compares with Utah'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 (50)

SR-163

COUNTY ROAD

SR-163

SR-162

NO DATA ENTERED

COUNTY ROAD.#236

US-191 (SR-191)

COUNTY ROAD

SR-163

SR-262

NEEDLES ENTRANCE R

IRR BIA RTE N5099

SR-162

SR-163

IRR BIA RTE N6325

SR-162

US-191 (SR-191)

US-191 (SR-191

SR-163

SR-95

LASAL MT. LOOP RD.

SR-95

US-491

SR-262

SR-262

US-191 (SR-191)

US-191 (SR-191)

NEEDLES ENTRANCE R

NEEDLES ENTRANCE R

COUNTY ROAD

US-191 (SR-191)

SR-162

County Rd

SR-163

SR-163

SR-95

US-191 (SR-191)

US-191 (SR-191)

IRR BIA RTE 6440

IRR BIA RTE N6310

SR-276

SR-276

SR-276

SR-95

McElmo Creek RD

US-191 (SR-191)

SR-163

SR-162

SR-162

SR-95

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