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I-25 Nbl over WYO 312 (South Street)

Platte County, Wyoming · rated Fair in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

I-25 Nbl over WYO 312 (South Street) in Platte County, Wyoming, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
It was built in 1975, making it 50 years old at the 2025 inventory.
It carries about 3,657 vehicles a day (traffic count year 2024).
Its listed owner is the state highway agency.
It is one of 94 of the 159 inventoried bridges in Platte County rated fair (59.1%); 15 (9.4%) are rated poor.
A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.

Component ratings

Source: FHWA National Bridge Inventory, 2025 data as reported by the Wyoming department of transportation.

Bridge	Built	Vehicles/day	Condition
US 87 Bus over I-25	1975	6,322	Good
US 26 over North Platte River	1983	4,832	Fair
I-25 NBL and SBL over Rock Creek	1975	3,865	Fair
I-25 Nbl over Machinery Pass	1966	3,743	Poor
I-25 Nbl over Laramie River	1966	3,743	Good
I-25 Nbl over Laramie River Road	1966	3,743	Fair