The short version
- Posted signs always govern. Limits in the data may be missing, outdated or wrong.
- It stays on your phone. Your location is matched to the built-in data on the device and is never sent anywhere.
- It is free to download. The parts derived from OpenStreetMap are offered here under the Open Database License, with the script that builds the file.
What the data is
One file, street_limits.bin, holds about 65,000 road pieces in the Los Angeles area (33.70° to 34.35° N, 118.70° to 118.10° W). Each piece has its geometry, its posted limit in each direction (or none when the limit is unknown), its road class, its name and the source of its limit. The app reads the file in place and matches each GPS fix to the street you are driving on.
Where several sources cover a street, the more specific one wins, in this order:
- Official documents: City of Glendale Municipal Code 10.24.020, and LADOT Speed Safety System program documents for a few camera streets.
- LADOT’s layer of streets posted 35 mph or less (January 2025).
- LADOT’s Speed Limit Map, with the AB 43 speed limit reductions applied.
- LADOT’s 25 mph layer for City of Los Angeles local streets (the California prima facie limit, as LADOT labels it).
- Los Angeles County Public Works, for county roads.
- Caltrans District 7, for freeway mainlines.
- OpenStreetMap, only where none of the above covers a road.
Not included: school-zone and time-of-day limits, and advisory speeds. Inside a speed camera’s segment, the app shows the camera’s own posted limit instead.
Sources and credits
- Speed limit data: City of Los Angeles Department of Transportation.
- Speed limits: City of Glendale Municipal Code 10.24.020.
- Contains data from County of Los Angeles, Department of Public Works, Speed Network; eGIS road centerlines. Not endorsed by the County.
- Source: California Department of Transportation (Caltrans), District 7.
- Speed limit data © OpenStreetMap contributors, available under the Open Database License.
The full list, with every layer’s address and retrieval date, is in the notice file below.
Speed Cams is not affiliated with or endorsed by LADOT, the City of Los Angeles, the City of Glendale, the County of Los Angeles, Caltrans or the OpenStreetMap Foundation.
Download
The road pieces with source codes 0 and 1 are derived from OpenStreetMap and form a Derivative Database under the Open Database License 1.0. They are offered here, in the exact file the app ships, together with the script and inputs that build it.
| File | What it is | Size |
|---|---|---|
| street_limits.bin | The dataset, exactly as built into the app (format version 2). SHA-256 863d1724ee2fa11f852676f357507cbdd74e7dc92be397065c0cfc7f5c84b783 | 2.8 MB |
| street_limits.NOTICE.txt | Sources, credits, license and the disclaimer | 5 KB |
| street_limits.manifest.json | Machine-readable manifest: every source with its address, query, count and retrieval time; counts and checks | 20 KB |
| build_speed_limits.py | The script that builds the file (Python standard library only). Its opening comment documents the file format. | 190 KB |
| street_limits_overrides.json | Limits taken from official documents, each with its citation | 7 KB |
| street_limits_suppress.json | OpenStreetMap values removed because an official document contradicts them | 1 KB |
OpenStreetMap snapshot: October 27, 2026. To rebuild the file, run python3 -I build_speed_limits.py build; it downloads the same public layers and OpenStreetMap extracts.
License texts: Open Database License 1.0 · OpenStreetMap copyright and license. A wrong limit from OpenStreetMap can be fixed on OpenStreetMap.
Contact
Found a wrong limit, or have a question about the data? Email support@speedcam.cc.