County profile · official public datasets

Platte County, WY

160 public highway bridges tracked in the FHWA National Bridge Inventory: 31.3% rated Good, 60% Fair, 8.8% Poor.

160
Public bridges: 31.3%
Good condition: 8.8%
Poor condition

The verdict

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

Platte 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.

16th
of 23 on Poor share: 8.8%
Poor-condition share: 160
public highway bridges: 1970
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.

Platte County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Platte County ranks #16 of 23 Wyoming counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.8%). Platte County, Wyoming contains 160 public highway bridges. Roughly 31.3% are rated “Good,” 60% “Fair,” and 8.8% “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

160

Public highway bridges in Platte County

Good condition

31.3%

50 of 160 rated 7-9

Fair condition

60%

96 of 160 rated 5-6

Poor condition

8.8%

14 of 160 rated 4 or below

In-state Poor-share rank

#16 of 23

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

Condition distribution

Share of 160 NBI-tracked bridges by lowest applicable component rating.

Good

31.3% (50)

Fair

60% (96)

Poor

8.8% (14)

Platte County's Poor-condition bridges carry 15,376 vehicle crossings a day

That is 5.1% of the county's reported daily bridge traffic on 8.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,098 crossings a day against 2,117 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 160 of 160 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

66.3% of Platte County's bridges have passed the 50-year mark

106 of the 160 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 31.3% 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 22.6% of the county's Poor-condition bridge traffic

I-25 NBL over Machinery Pass, built 1972, carries 3,471 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 14-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 15,376 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

4
1930s

6
1940s

3
1950s

21
1960s

48
1970s

44
1980s

17
1990s

6
2000s

3
2010s

8

What this shows Construction peaked in the 1960s, when 48 of the county's bridges still in the inventory were built, which is 30% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1970, 6 years older than the Wyoming average of 1976.

How Platte County compares with Wyoming's closest counties by inventory size

The 5 Wyoming counties nearest Platte County in number of bridges, with their condition splits. Its 8.8% Poor share is the 5th-lowest of these 6. Its average build year of 1970 against a peer-group mean of 1977 is 7 years older.

Showing the 5 closest of 22 Wyoming counties eligible for comparison.

Bridge inventory size and condition shares for Platte County and the 5 Wyoming counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Fremont County	177	47.5%	46.3%	6.2%	1981
Crook County	176	30.7%	67.6%	1.7%	1974
Sheridan County	170	23.5%	71.8%	4.7%	1975
Platte County (this page)	160	31.3%	60%	8.8%	1970
Campbell County	152	25.7%	71.7%	2.6%	1980
Converse County	137	14.6%	72.3%	13.1%	1974

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

Similar inventory size

Nearest county inventories outside WY (160 bridges here).

Clay County, KY · 160 bridges
Kittson County, MN · 160 bridges
Rio Arriba County, NM · 160 bridges
Delaware County, OK · 160 bridges

Similar average build year

Nearest mean year-built outside WY (1970 here).

Hamilton County, OH · avg 1970 · 783 bridges
Yavapai County, AZ · avg 1970 · 543 bridges
Garfield County, OK · avg 1970 · 504 bridges
San Luis Obispo County, CA · avg 1970 · 401 bridges

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

All 160 Good 50 Fair 96 Poor 14

Fair-condition bridges (96)

Sort:

Platte County Bridge Snapshot

Condition distribution

Platte County's Poor-condition bridges carry 15,376 vehicle crossings a day

66.3% of Platte County's bridges have passed the 50-year mark

One structure carries 22.6% of the county's Poor-condition bridge traffic

How Platte County compares with Wyoming'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 (96)

14th Street

12th Street

Pl Cnty Rd 59

Pl Cnty Rd 59

Pl Cnty Rd 133

I-25 NBL

I-25 NBL

I-25 SBL

WYO 34

I-25 Service Road

US 26

WYO 310

Pl Cnty Rd 81

Pl Cnty Rd 204

I-25 NBL

I-25 SBL

I-25 NBL

I-25 SBL

I-25 NBL

I-25 SBL

WYO 34

WYO 319

I-25 SBL

US 26

WYO 34

I-25 SBL

I-25 NBL

I-25 SBL

I-25 NBL

Pl Cnty Rd 109S

Pl Cnty Rd 245-1

I-25 SBL Off Ramp

WYO 34

Pl Cnty Rd 133

I-25 SBL

I-25 NBL

I-25 NBL

WYO 320

Pl Cnty Rd 269

WYO 34

Pl Cnty Rd 272

I-25 NBL

WYO 34

I-25 NBL

I-25 SBL

Skyline Drive

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