Mobile Broadband Testing

CalSPEED: Measuring Mobile Broadband in California

Mobile networks reach millions of people — but how well do they actually perform? CalSPEED helps answer that question with independent data collected at more than 4,000 locations across urban neighborhoods, rural communities, and Tribal lands.

CalSPEED’s Mobile Field Test Program measures, maps, and reports real‑world mobile broadband service throughout the state. The program collects measurements from devices in the field using custom‑developed, open‑source software. The results are publicly accessible and used by policymakers, advocates, researchers, and consumers to assess mobile broadband services across California.

What does CalSPEED measure?

CalSPEED collects data about the cellular mobile networks of AT&T, T‑Mobile, and Verizon in California, including:

• Download & Upload Speeds — How fast can data move to and from your device?
• Latency (Round‑Trip Time) — How quickly does your network respond?
• Jitter (Delay Variation) — Is performance steady, or does it vary unpredictably?
• Data Loss — Are packets being dropped during transmission?
• Dozens of other metrics.

Test results reflect performance at a specific place and time; actual experience varies by location, terrain/buildings, network usage, and device.

What can you do with CalSPEED data?

CalSPEED publishes point‑in‑time measurements of mobile broadband performance at particular locations. Stakeholders can use these results to:

• Support evidence‑based decisions — Incorporate CalSPEED results into your analysis and research so decisions are aligned with observed network performance.
• Monitor drive test progress — Use Progress Tracker dashboards to see visited sites, completed tests, and where results are missing during field testing.
• View performance at tested sites — See download/upload speeds and latency recorded during each test session.
• Add local context — Enrich results with publicly available information (e.g., county/city/place names, U.S. Census sociodemographic data, and fire‑threat designations) to understand where measurements were taken.
• Plan follow‑up work — Identify places that merit additional measurement, validation, or community engagement around mobile service.