I-405 over I-5
GoodSnohomish County, Washington · 3.3 N JCT SR 527 · Structure no. 0011855A0000000
- Built
- 1981
- 44 years old
- Condition
- Good
- inspected April 2024
- Type
- Stringer/Multi-beam or Girder
- Steel Continuous
- Length
- 560 ft
- 4 main spans
- Daily traffic
- 17,871
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I-405 over I-5 is a steel continuous stringer/multi-beam or girder carrying I-405 over I-5 in Snohomish County, Washington. It was built in 1981, so it is 44 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 17,871 vehicles a day, roughly 5% of them trucks, projected to reach 27,400 by 2039. The structure is 560 ft (170.7 m) long and 55 ft wide. If it were closed, the detour would be 6.2 mi (10 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 over I-5 built?
It was built in 1981, making it 44 years old in 2025.
What condition is I-405 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 April 2024.
How much traffic does I-405 over I-5 carry?
About 17,871 vehicles per day (2023 count), of which roughly 5% are trucks.
How long is I-405 over I-5?
The structure is 560 ft (170.7 m) long with a longest span of 165 ft (50.3 m) and a deck 55 ft wide.
Who owns I-405 over I-5?
It is owned by the State Highway Agency.