I-405 S-W Ramp over Northup Way
GoodKing County, Washington · 0.1 N JCT SR 520 · Structure no. 0007596G0000000
- Built
- 1966
- 59 years old
- Condition
- Good
- inspected July 2021
- Type
- Slab
- Concrete Continuous
- Length
- 136 ft
- 3 main spans
- Daily traffic
- 9,907
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I-405 S-W Ramp over Northup Way is a concrete continuous slab carrying I-405 S-W Ramp over Northup Way in King County, Washington. It was built in 1966, so it is 59 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 9,907 vehicles a day, roughly 5% of them trucks, projected to reach 15,568 by 2039. The structure is 136 ft (41.5 m) long and 27 ft wide. If it were closed, the detour would be 3.1 mi (5 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 I-405 S-W Ramp over Northup Way built?
It was built in 1966, making it 59 years old in 2025.
What condition is I-405 S-W Ramp over Northup Way 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 July 2021.
How much traffic does I-405 S-W Ramp over Northup Way carry?
About 9,907 vehicles per day (2023 count), of which roughly 5% are trucks.
How long is I-405 S-W Ramp over Northup Way?
The structure is 136 ft (41.5 m) long with a longest span of 54 ft (16.5 m) and a deck 27 ft wide.
Who owns I-405 S-W Ramp over Northup Way?
It is owned by the State Highway Agency.