S178th ST over I-5
GoodKing County, Washington · 4.0 N JCT SR 516 · Structure no. 0007401A0000000
- Built
- 1964
- 61 years old
- Condition
- Good
- inspected March 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 322 ft
- 4 main spans
- Daily traffic
- 13,400
- 2002 count
- Owner
- State
- State Highway Agency
About this bridge
S178th ST over I-5 is a prestressed concrete stringer/multi-beam or girder carrying S178th ST over I-5 in King County, Washington. It was built in 1964, so it is 61 years old, older 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 13,400 vehicles a day, roughly 1% of them trucks, projected to reach 23,423 by 2036. The structure is 322 ft (98.1 m) long and 33 ft wide. If it were closed, the detour would be 3.7 mi (6 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 | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was S178th ST over I-5 built?
It was built in 1964, making it 61 years old in 2025.
What condition is S178th ST over I-5 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 March 2024.
How much traffic does S178th ST over I-5 carry?
About 13,400 vehicles per day (2002 count), of which roughly 1% are trucks.
How long is S178th ST over I-5?
The structure is 322 ft (98.1 m) long with a longest span of 102 ft (31.1 m) and a deck 33 ft wide.
Who owns S178th ST over I-5?
It is owned by the State Highway Agency.