Did you know? The oldest bridge in the NBI was built in 1697.
Did you know? The oldest bridge in the NBI was built in 1697.
Why did the bridge go to therapy? It had too many spans of anxiety.
over SWINOMISH SLOUGH
0.95 JCT MORRIS ON MAPLE
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This bridge has a Fair overall condition rating of 6 out of 9. While it is not classified as structurally deficient, it shows some deterioration that is being monitored.
The bridge carries 3,101 vehicles per day and is 69 years old.
Its sufficiency rating of 49.2 places it below the national average of 63.6.
The NBI records a navigation clearance of 75 feet — the minimum vertical space below the bridge deck. The total height of the bridge structure (including towers, railings, and superstructure) may be higher.
For travelers with bridge anxiety
This bridge has some features that may be challenging for travelers with bridge anxiety. See the tips below for a more comfortable crossing.
This bridge is 797 feet long — a moderate crossing, about 30 seconds.
An arch bridge design with some openness to the surroundings.
About 75 feet above ground — an elevated crossing, similar to a 5-10 story building.
About 3,101 vehicles cross daily — light traffic, a smooth crossing.
The deck is 30 feet wide with 1-2 lanes — a narrower crossing.
This bridge crosses over water. Focus on the road ahead — the water is far below.
This comfort score is designed to help individuals with bridge anxiety plan their travel. All bridges in the National Bridge Inventory are regularly inspected and deemed safe for travel. This is not medical advice — if you experience severe anxiety, please consult a healthcare professional.
Year Built
1957
69 years old
Structure Type
Steel Arch (Thru)
Total Length
797 ft
242.9 m
Deck Width
30 ft
9.1 m
Spans
1
sections between supports
Max Span
580 ft
longest unsupported section (176.8 m)
Traffic Lanes
2 lanes
Two-way traffic
Clearance Below
75 ft
navigation clearance under deck
Clearance height compared to familiar objects
Height shown is the navigation clearance below the bridge deck. The total height of the bridge structure (including towers and superstructure) may be higher.
Daily Traffic
3,101vehicles/day
48.38575°N, 122.50163°W
Steel Arch (Thru)
A steel arch bridge uses a curved steel structure to carry loads primarily through compression. These bridges are known for their elegant appearance and structural efficiency.
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Data from the National Bridge Inventory (NBI), maintained by the Federal Highway Administration (FHWA).
Data year: 2025. Conditions may have changed since the last inspection.
This information is provided for educational and informational purposes only. It should not be used as the sole basis for any decisions related to bridge safety or transportation planning. Always consult official sources and local authorities for the most current data.