County profile · official public datasets

Salt Lake County, UT

659 public highway bridges tracked in the FHWA National Bridge Inventory: 23.8% rated Good, 72.4% Fair, 3.8% Poor.

659
Public bridges: 23.8%
Good condition: 3.8%
Poor condition

The verdict

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

Salt Lake 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.

22nd
of 29 on Poor share: 3.8%
Poor-condition share: 659
public highway bridges: 1993
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.

Salt Lake County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Salt Lake County ranks #22 of 29 Utah counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 3.8%). Salt Lake County, Utah contains 659 public highway bridges. Roughly 23.8% are rated “Good,” 72.4% “Fair,” and 3.8% “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

659

Public highway bridges in Salt Lake County

Good condition

23.8%

157 of 659 rated 7-9

Fair condition

72.4%

477 of 659 rated 5-6

Poor condition

3.8%

25 of 659 rated 4 or below

In-state Poor-share rank

#22 of 29

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

Condition distribution

Share of 659 NBI-tracked bridges by lowest applicable component rating.

Good

23.8% (157)

Fair

72.4% (477)

Poor

3.8% (25)

Salt Lake County's Poor-condition bridges carry 395,180 vehicle crossings a day

That is 1.4% of the county's reported daily bridge traffic on 3.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 15,807 crossings a day against 36,885 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 633 of 659 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

17.3% of Salt Lake County's bridges have passed the 50-year mark

114 of the 659 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 23.8% 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 25.2% of the county's Poor-condition bridge traffic

SR-201 (2100 S.ST) over 3200 WEST ST. INT. X-RD., built 1980, carries 99,668 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 25-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 395,180 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1930s

10
1940s

5
1950s

16
1960s

48
1970s

66
1980s

112
1990s

147
2000s

142
2010s

76
2020s

37

What this shows Construction peaked in the 1990s, when 147 of the county's bridges still in the inventory were built, which is 22.3% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year is 1993, 9 years newer than the Utah average of 1984.

How Salt Lake County compares with Utah's closest counties by inventory size

The 5 Utah counties nearest Salt Lake County in number of bridges, with their condition splits. Its 3.8% Poor share is the 5th-lowest of these 6. Its average build year of 1993 against a peer-group mean of 1988 is 5 years newer.

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

Bridge inventory size and condition shares for Salt Lake County and the 5 Utah counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Salt Lake County (this page)	659	23.8%	72.4%	3.8%	1993
Utah County	271	37.3%	61.6%	1.1%	1995
Box Elder County	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

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

Similar inventory size

Nearest county inventories outside UT (659 bridges here).

Sumner County, KS · 659 bridges
Bell County, TX · 660 bridges
Alameda County, CA · 658 bridges
Lancaster County, NE · 661 bridges

Similar average build year

Nearest mean year-built outside UT (1993 here).

Marshall County, MS · avg 1993 · 255 bridges
Rowan County, NC · avg 1993 · 245 bridges
Cabarrus County, NC · avg 1993 · 236 bridges
Daviess County, IN · avg 1993 · 221 bridges

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

All 659 Good 157 Fair 477 Poor 25

Fair-condition bridges (477)

Sort:

Salt Lake County Bridge Snapshot

Condition distribution

Salt Lake County's Poor-condition bridges carry 395,180 vehicle crossings a day

17.3% of Salt Lake County's bridges have passed the 50-year mark

One structure carries 25.2% of the county's Poor-condition bridge traffic

How Salt Lake 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 (477)

SR-71 126th SO.ST.

I-15 (SR-15) NBL

I-15 (SR-15) NBL

US-89 (SR-89)

I-15 (SR-15) NBL

I-15 (SR-15) NBL

I-15 (SR-15) SBL

VISTA STATION BLVD

I-215 (SR-215) NBL

RP.I215EB TO I15SB

I-15 (SR-15) SBL

I-15 (SR-15) NBL

I-15 (SR-15) SBL

SR-151 106TH SOUTH

RP.I15SB toSR201WB

I-15 (SR-15) SBL

I-80 (SR-80) WBL

I-15 (SR-15) NBL

RP.I215SB TO I80EB

I-80 (SR-80) EBL

RP.I-15NB toI-80EB

I-15 (SR-15) SBL

I-15 NB COL-DIST.

I-80 (SR-80) EBL

I-215 (SR-215) SBL

I-80WB (SR-80)

GOLDEN PHEASANT DR

SR-71 123rd SOUTH

I-15 (SR-15) NBL

I-15 (SR-15) SBL

RAMP to I-80 EB

RP.2100 S.to I15SB

US-89 (SR-89)

SR-154 -BNGTR.HWY.

RP.I215NB TO I80EB

I-15 (SR-15) SBL

3950 SOUTH STREET

SR-154 BNGTR.HWY.

UNION PARK AVE.

AIRPORT SHUTTLE RD

I-80 (SR-80)EBL

12000 SOUTH STREET

I-15 (SR-15) NBL

I-80 WB COL-DIST.

SR-154 -BNGTR.HWY.

I-15

1300 EAST STREET

I-80 (SR-80) EBL

SR-154 -BNGTR.HWY.

I-80 (SR-80) WBL

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