Old Hwy 99 over Prairie Creek
Thurston County, Washington · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Old Hwy 99 over Prairie Creek in Thurston County, Washington, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 8 (very good condition) on the 0-9 scale.
- It was built in 2010, making it 15 years old at the 2025 inventory.
- It carries about 11,240 vehicles a day (traffic count year 2021).
- Its listed owner is the county highway agency.
- It is one of 118 of the 199 inventoried bridges in Thurston County rated good (59.3%); 2 (1.0%) 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 June 2023, 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 → (46.79662, -123.01201)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 8 | 8 | Very good condition |
| Superstructure | 8 | 8 | Very good condition |
| Substructure | 8 | 8 | Very good condition |
Bridge details
| Structure | Prestressed concrete slab |
| Length | about 62 ft |
| Location | 1. S Jct I-5 |
| NBI structure number | 088277000000000 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | June 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Washington department of transportation.
Busiest bridges in Thurston County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-5 over Owr N RR | 1957 | 69,477 | Fair |
| I-5 over Henderson Blvd | 1957 | 69,477 | Good |
| I-5 over Nisqually River | 1937 | 62,815 | Fair |
| I-5 over Nisqually River | 1967 | 62,815 | Fair |
| US 101 NB over I-5 Ramps Street | 1990 | 62,306 | Good |
| I-5 over Pacific Ave | 1957 | 59,814 | Fair |
All bridges nearby: Thurston County, WA bridge conditions · every bridge in Thurston County · Washington bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.