West Contra Costa Collision Map

EMS dispatch transcripts vs. SWITRS official records

— incidents — dispatch — SWITRS gap: —

West Contra Costa Collision Map

3,189
crashes mapped
5
jurisdictions
2014–2025
date range

This map tracks bicycle and pedestrian collisions in El Cerrito, Richmond, Albany, and Berkeley — comparing official SWITRS records against EMS dispatch radio transcripts to measure how many crashes go unreported.

Data sources

SWITRS (currently shown) — California's official Statewide Integrated Traffic Records System, exported from tims.berkeley.edu. Covers only crashes that were reported to law enforcement.

EMS Dispatch (coming soon) — extracted from Broadcastify scanner archive recordings using Whisper transcription and Claude. Will reveal crashes that were responded to by EMS but never filed as police reports.

Methodology

About 40% of SWITRS records lack GPS coordinates and are geocoded using Claude (address normalization) and the Google Maps API. Geocoded incidents are validated against a West Contra Costa bounding box.

Incident

Collision type

Bicycle
Pedestrian

Size = severity

Fatal
Severe injury
Other visible injury
Complaint of pain
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