I-25 Sbl over WYO 312 (South Street)
Platte County, Wyoming · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- I-25 Sbl over WYO 312 (South Street) in Platte County, Wyoming, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- 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 3,526 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.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated April 2021, on a 24-month routine inspection cycle.
- 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.
View this bridge on a map → (42.05139, -104.96559)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous steel frame |
| Length | about 145 ft |
| Location | Wheatland Marginal |
| NBI structure number | CBF |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | April 2021 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Wyoming department of transportation.
Busiest bridges in Platte County
| 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 |
All bridges nearby: Platte County, WY bridge conditions · every bridge in Platte County · Wyoming bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.