County profile · official public datasets

Box Elder County, UT

184 public highway bridges tracked in the FHWA National Bridge Inventory: 23.4% rated Good, 70.7% Fair, 6% Poor.

184
Public bridges: 23.4%
Good condition: 6%
Poor condition

The verdict

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

Box Elder 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.

26th
of 29 on Poor share: 6%
Poor-condition share: 184
public highway bridges: 1977
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.

Box Elder County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Box Elder County ranks #26 of 29 Utah counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6%). Box Elder County, Utah contains 184 public highway bridges. Roughly 23.4% are rated “Good,” 70.7% “Fair,” and 6% “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

184

Public highway bridges in Box Elder County

Good condition

23.4%

43 of 184 rated 7-9

Fair condition

70.7%

130 of 184 rated 5-6

Poor condition

11 of 184 rated 4 or below

In-state Poor-share rank

#26 of 29

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

Condition distribution

Share of 184 NBI-tracked bridges by lowest applicable component rating.

Good

23.4% (43)

Fair

70.7% (130)

Poor

6% (11)

Box Elder County's Poor-condition bridges carry 10,641 vehicle crossings a day

That is 0.6% of the county's reported daily bridge traffic on 6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 967 crossings a day against 10,462 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 182 of 184 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

46.7% of Box Elder County's bridges have passed the 50-year mark

86 of the 184 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 23.4% 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 79.1% of the county's Poor-condition bridge traffic

SR-126 over I-15 (SR-15) NBL AND SBL, built 1968, carries 8,412 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 11-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 10,641 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

1
1920s

1
1930s

6
1940s

12
1950s

16
1960s

36
1970s

35
1980s

24
1990s

23
2000s

11
2010s

17
2020s

2

What this shows Construction peaked in the 1960s, when 36 of the county's bridges still in the inventory were built, which is 19.6% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1977, 7 years older than the Utah average of 1984.

How Box Elder County compares with Utah's closest counties by inventory size

The 5 Utah counties nearest Box Elder County in number of bridges, with their condition splits. Its 6% Poor share is the 6th-lowest of these 6. Its average build year of 1977 against a peer-group mean of 1985 is 8 years older.

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

Bridge inventory size and condition shares for Box Elder County and the 5 Utah counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Box Elder County (this page)	184	23.4%	70.7%	6%	1977
Washington County	177	20.3%	78.5%	1.1%	1987
Sevier County	157	19.1%	80.3%	0.6%	1983
Davis County	139	28.8%	70.5%	0.7%	1996
Summit County	138	14.5%	81.2%	4.3%	1982
Weber County	129	14.7%	80.6%	4.7%	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 Box Elder 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 Box Elder County, both outside Utah so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside UT (184 bridges here).

Independence County, AR · 184 bridges
Mills County, IA · 184 bridges
Henderson County, KY · 184 bridges
Adams County, OH · 184 bridges

Similar average build year

Nearest mean year-built outside UT (1977 here).

San Diego County, CA · avg 1977 · 1,632 bridges
King County, WA · avg 1977 · 1,238 bridges
Riverside County, CA · avg 1977 · 1,117 bridges
Shelby County, TN · avg 1977 · 1,077 bridges

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

All 184 Good 43 Fair 130 Poor 11

Fair-condition bridges (130)

Sort:

Box Elder County Bridge Snapshot

Condition distribution

Box Elder County's Poor-condition bridges carry 10,641 vehicle crossings a day

46.7% of Box Elder County's bridges have passed the 50-year mark

One structure carries 79.1% of the county's Poor-condition bridge traffic

How Box Elder 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

Fair-condition bridges (130)

I-15 (SR-15) NBL

CO RD (CALLS FORT)

COUNTY ROAD

SR-126

CO.RD.-INTCHG.X-RD

I-15 (SR-15) NBL

I-15 (SR-15) SBL

SR 13

US-91 (SR-91)

I-15 SB OFF RAMP

FOREST ST.INT.X-RD

US-89 (SR-89)

16800 N.ST FA# 506

10800 WEST-CO.RD.

I-15 (SR-15) SBL

COUNTY ROAD

TOWN RD. 8800 NO.

I-15 (SR-15) SBL

I-15 NB ON-RAMP

COUNTY ROAD

HONEYVILLE CITY ST

I-15 (SR-15) NBL

I-15 (SR-15) SBL

COUNTY RD. FA.#504

I-15 (SR-15) SBL

ELWOOD TOWN ROAD

I-84 (SR-84)

I-84 (SR-84)

CO. RD. 20800 NO.

I-15 NB ON-RAMP

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