Bridges: the original social network. Connecting communities since 850 BC.
Bridges: the original social network. Connecting communities since 850 BC.
Did you know? The oldest bridge in the NBI was built in 1697.
over DUWAMISH RIVER
0.1 N JCT SR 509
Parametric wireframe generated from real NBI dimensions. Drag to rotate, scroll to zoom.
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This bridge has a Fair overall condition rating of 5 out of 9. While it is not classified as structurally deficient, it shows some deterioration that is being monitored.
The bridge carries 48,204 vehicles per day and is 70 years old (reconstructed in 1998).
Its sufficiency rating of 59.0 places it below the national average of 63.6.
The NBI records a navigation clearance of 41 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 3010 feet long — a longer crossing, over 1 minute.
A movable bridge — it may occasionally stop for boat traffic.
About 41 feet above ground — moderate height, similar to a 3-5 story building.
About 48,204 vehicles cross daily — moderate traffic, some congestion possible.
The deck is 58 feet wide with 3-4 lanes — standard width.
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
1956
70 years old (rebuilt 1998)
Structure Type
Steel Movable (Bascule)
Total Length
3,010 ft
917.4 m
Deck Width
58 ft
17.7 m
Spans
1
sections between supports
Max Span
277 ft
longest unsupported section (84.4 m)
Traffic Lanes
3 lanes
One-way traffic
Clearance Below
41 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
48,204vehicles/day
47.53758°N, 122.33469°W
Steel Movable (Bascule)
A movable bridge can change position to allow passage of boats or other traffic. Steel movable bridges include lift, bascule (drawbridge), and swing types.
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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.