Thorp Prairie Road over Hiline Canal
Kittitas County, Washington · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Thorp Prairie Road over Hiline Canal in Kittitas County, Washington, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 1979, making it 46 years old at the 2025 inventory.
- It carries about 432 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 133 of the 313 inventoried bridges in Kittitas County rated good (42.5%); 35 (11.2%) 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 October 2024, on a 24-month routine inspection cycle.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (47.12373, -120.80108)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Continuous prestressed concrete tee beam |
| Length | about 79 ft |
| Location | 01.38 E I-90 X-ing |
| NBI structure number | 081326000000000 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | October 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 9: foundations on dry land well above flood elevations |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Washington department of transportation.
Busiest bridges in Kittitas County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-90 over Coal Creek | 1928 | 18,069 | Fair |
| I-90 over Coal Creek | 1956 | 18,069 | Poor |
| I-90 over Animal Crossing | 2010 | 18,069 | Good |
| I-90 over Animal Crossing | 2012 | 18,069 | Good |
| I-90 over Gold Creek | 2011 | 18,069 | Fair |
| I-90 over Gold Creek | 2012 | 18,069 | Good |
All bridges nearby: Kittitas County, WA bridge conditions · every bridge in Kittitas County · Washington bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.