Seattle Metro Explorer
A living portrait of the Seattle metro. Travel time corridors color-coded by congestion, ferries moving across the Sound in real time, live highway cameras on click, mountain pass conditions, and highway alerts.
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Layers
What this proves
Real-time public APIs, live animated ferry positions, highway camera feeds, and travel time congestion ratios across the Puget Sound region, built in one session.
How it works
What it does
The Seattle Metro Explorer is a real-time map of the Puget Sound region that pulls from 5 live WSDOT and WSF data feeds:
- Travel Times - ~100 named highway corridors with current vs average time, color-coded green/yellow/orange/red by congestion ratio
- Ferry Positions - Every Washington State Ferry in service, updated every 15 seconds, showing heading, speed, route, and ETA
- Highway Cameras - 400+ WSDOT traffic cameras. Click any purple dot to see the live snapshot
- Highway Alerts - Active incidents, construction, and road closures
- Mountain Passes - Current conditions for Snoqualmie, Stevens, and White Pass
How it works
The build uses a server-side API proxy (/api/seattle-metro) that caches WSDOT responses to avoid hammering the public APIs. Travel times cache for 2 minutes, ferries for 10 seconds, cameras for 5 minutes. The client polls ferries every 15 seconds for smooth position updates.
The map renders with Mapbox GL JS on a dark basemap. Travel time corridors are plotted as colored markers at corridor start points. Ferries render as directional triangles rotated by heading. Cameras and alerts lazy-load when you toggle them on (no wasted API calls for hidden layers).
All data comes from free public APIs: WSDOT Traveler Information API and WSF Vessel Locations API. The only requirement is a free API key registered via email at wsdot.wa.gov.
Why this exists
No other city data explorer shows live ferry positions. The combination of real-time travel times + animated vessels + live cameras creates a "living portrait" effect that makes the metro feel alive, not just mapped.
This build proves that compelling real-time data visualization can be built in a single session using AI-augmented development, with free public data sources.
Get the next build and workflow breakdown.