SR 99 over Terrain
GoodKing County, Washington · 3.3 N JCT SR 509 · Structure no. 0017847B0000000
- Built
- 2011
- 14 years old
- Condition
- Good
- inspected October 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete Continuous
- Length
- 951 ft
- 7 main spans
- Daily traffic
- 28,886
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
SR 99 over Terrain is a prestressed concrete continuous stringer/multi-beam or girder carrying SR 99 over Terrain in King County, Washington. It was built in 2011, so it is 14 years old, younger than the Washington average of 49.8 years.
The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 28,886 vehicles a day, roughly 4% of them trucks, projected to reach 47,503 by 2039. The structure is 951 ft (289.9 m) long and 58 ft wide. If it were closed, the detour would be 1.9 mi (3 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 8 Very Good | No problems noted. |
| Superstructure | 8 Very Good | No problems noted. |
| Substructure | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was SR 99 over Terrain built?
It was built in 2011, making it 14 years old in 2025.
What condition is SR 99 over Terrain in?
The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in October 2024.
How much traffic does SR 99 over Terrain carry?
About 28,886 vehicles per day (2023 count), of which roughly 4% are trucks.
How long is SR 99 over Terrain?
The structure is 951 ft (289.9 m) long with a longest span of 150 ft (45.7 m) and a deck 58 ft wide.
Who owns SR 99 over Terrain?
It is owned by the State Highway Agency.