Pioneer Highway over Thomsen Slough
FairSnohomish County, Washington · 8.0 E JCT SR 532 · Structure no. 0000364B0000000
- Built
- 1919
- 106 years old, rebuilt 2003
- Condition
- Fair
- inspected July 2024
- Type
- Arch - Deck
- Concrete
- Length
- 40 ft
- 1 main span
- Daily traffic
- 4,051
- 2022 count
- Owner
- County
- County Highway Agency
About this bridge
Pioneer Highway over Thomsen Slough is a concrete arch - deck carrying Pioneer Highway over Thomsen Slough in Snohomish County, Washington. It was built in 1919 and reconstructed in 2003, so it is 106 years old, older than the Washington average of 49.8 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
It carries about 4,051 vehicles a day, roughly 14% of them trucks, projected to reach 6,000 by 2046. The structure is 40 ft (12.2 m) long and 31 ft wide. If it were closed, the detour would be 6.2 mi (10 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 8 Very Good | No problems noted. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Pioneer Highway over Thomsen Slough built?
It was built in 1919, making it 106 years old in 2025. It was reconstructed in 2003.
What condition is Pioneer Highway over Thomsen Slough in?
The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in July 2024.
How much traffic does Pioneer Highway over Thomsen Slough carry?
About 4,051 vehicles per day (2022 count), of which roughly 14% are trucks.
How long is Pioneer Highway over Thomsen Slough?
The structure is 40 ft (12.2 m) long with a longest span of 40 ft (12.2 m) and a deck 31 ft wide.
Who owns Pioneer Highway over Thomsen Slough?
It is owned by the County Highway Agency.