SR 18 over Terrain
GoodKing County, Washington · 6.3 E JCT SR 169 · Structure no. 0015927A0000000
- Built
- 2001
- 24 years old
- Condition
- Good
- inspected October 2023
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 141 ft
- 1 main span
- Daily traffic
- 25,373
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
SR 18 over Terrain is a prestressed concrete stringer/multi-beam or girder carrying SR 18 over Terrain in King County, Washington. It was built in 2001, so it is 24 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 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 25,373 vehicles a day, roughly 17% of them trucks, projected to reach 38,039 by 2039. The structure is 141 ft (43 m) long and 52 ft wide. If it were closed, the detour would be 29.8 mi (48 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 | 7 Good | Some minor problems. |
| 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 18 over Terrain built?
It was built in 2001, making it 24 years old in 2025.
What condition is SR 18 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 2023.
How much traffic does SR 18 over Terrain carry?
About 25,373 vehicles per day (2023 count), of which roughly 17% are trucks.
How long is SR 18 over Terrain?
The structure is 141 ft (43 m) long with a longest span of 138 ft (42.1 m) and a deck 52 ft wide.
Who owns SR 18 over Terrain?
It is owned by the State Highway Agency.