I-405 over I-5
FairSnohomish County, Washington · 3.3 N JCT SR 527 · Structure no. 0011855C0000000
- Built
- 1982
- 43 years old
- Condition
- Fair
- inspected April 2024
- Type
- Stringer/Multi-beam or Girder
- Steel Continuous
- Length
- 646 ft
- 5 main spans
- Daily traffic
- 25,479
- 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 1982, so it is 43 years old, younger than the Washington average of 49.8 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
It carries about 25,479 vehicles a day, roughly 5% of them trucks, projected to reach 39,065 by 2039. The structure is 646 ft (196.9 m) long and 43 ft wide. If it were closed, the detour would be 6.2 mi (10 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| 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 1982, making it 43 years old in 2025.
What condition is I-405 over I-5 in?
The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in April 2024.
How much traffic does I-405 over I-5 carry?
About 25,479 vehicles per day (2023 count), of which roughly 5% are trucks.
How long is I-405 over I-5?
The structure is 646 ft (196.9 m) long with a longest span of 142 ft (43.3 m) and a deck 43 ft wide.
Who owns I-405 over I-5?
It is owned by the State Highway Agency.