Crunching the numbers on America's infrastructure...
Crunching the numbers on America's infrastructure...
Why did the bridge go to therapy? It had too many spans of anxiety.
over SR 522 SAMMAMISH R
8.7 N JCT SR 520
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 6 out of 9. While it is not classified as structurally deficient, it shows some deterioration that is being monitored.
The bridge carries 56,311 vehicles per day and is 58 years old (reconstructed in 1997).
Its sufficiency rating of 64.3 is above the national average of 63.6.
The NBI records a navigation clearance of 16 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 may cause some awareness for travelers with bridge anxiety, but has manageable characteristics.
This bridge is 1410 feet long — a moderate crossing, about 30 seconds.
A standard overpass design with solid barriers on each side.
About 16 feet above ground — standard overpass height.
About 56,311 vehicles cross daily — heavy traffic, congestion likely during rush hours.
The deck is 43 feet wide with 2-3 lanes — moderate 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
1968
58 years old (rebuilt 1997)
Structure Type
Concrete (Continuous) Box Beam (Multiple)
Total Length
1,410 ft
429.8 m
Deck Width
43 ft
13.1 m
Spans
13
sections between supports
Max Span
122 ft
longest unsupported section (37.2 m)
Traffic Lanes
3 lanes
One-way traffic
Clearance Below
16 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
56,311vehicles/day
47.75564°N, 122.18564°W
Concrete (Continuous) Box Beam (Multiple)
A concrete box beam bridge uses hollow rectangular concrete sections. The box shape provides excellent torsional resistance and allows for longer spans.
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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.