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LA County Mapped License Plate Readers
A free dataset from The Basin  ·  basin.la/data/index.html#la-alpr-cameras
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The full method, the column definitions and the known limits are written up and
available on request: data@basin.la

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ABOUT THIS DATASET
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LA-ALPR-CAMERAS
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Every automated license plate reader that volunteers have tagged in OpenStreetMap across
Los Angeles County's 88 incorporated cities, placed inside a Census city boundary and
joined to 2025 population and land area. Ships the city summary and the point-level table
behind it.

Published by The Basin (basin.la). Built 2026-08-16.


READ THIS BEFORE YOU USE IT
---------------------------

These are volunteer observations, not a register. No public inventory of automated
license plate readers exists for Los Angeles County. The locations here were surveyed and
tagged by OpenStreetMap contributors, many of them organised through the DeFlock project,
who photograph readers and record their positions.

That has three consequences, and none of them can be corrected downstream:

1. Every count is a floor. A city's number is what has been found, not what is there.
2. Coverage is uneven, and not randomly so. A city with an active local privacy
   community gets mapped more thoroughly than one without. The undercount is likely
   correlated with the same things everything else in this county is correlated with, so
   comparisons between two cities carry more risk than the headline totals do.
3. A mapped reader is an observed location, not a verified working camera. Nothing
   here establishes that a given reader is powered on.

Population and land area are firm 2025 Census figures. Any rate in this release is
therefore only as good as its numerator, which is the soft half.


WHAT IS IN THE BOX
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At the 2026-08-16 build: 3,127 mapped readers inside the 88 cities, of which 2,190 carry a
Flock Safety tag, plus 2,164 more outside every city limit. Seventy-nine cities have at
least one mapped Flock reader; four have no mapped reader of any kind.


PER-RESIDENT DENOMINATOR BREAKS IN THREE CITIES
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Industry (199 residents), Vernon (207) and Irwindale (1,439) are industrial districts
incorporated to be workplaces. Their daytime populations run to tens of thousands of people
who live elsewhere. A per-resident rate in those three cities describes commuters, not
residents, and they top the per-resident ranking for that reason alone. Both per-resident
columns are shipped because they are the right measure for most of the county, but they
should not be ranked without excluding or flagging those three.

Per square mile has the opposite bias: it rewards small cities and buries large ones. The
City of Los Angeles covers 470 square miles and will sit near the bottom of any density
ranking regardless of how many readers it has.


LICENSING
---------

The reader locations come from OpenStreetMap and are licensed ODbL 1.0, which is
share-alike. That is not the same as attribution, and it is why this release is not offered
for commercial license on the catalogue's usual terms. See "Terms: sources and rights" below.

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TERMS: SOURCES AND RIGHTS
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     because several catalogued datasets have no sources.py entry and the
     generator refuses to run until they do. Keep this file in step with

LA COUNTY MAPPED LICENSE PLATE READERS
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Sources, rights and terms. Licenses were read from each publisher on 2026-08-16.


WHAT THIS IS
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Not the records. The reader locations underneath this release were surveyed and tagged by
OpenStreetMap contributors, and the table below says exactly where to get them. What The
Basin added is the assembly: the Overpass extraction, the point-in-polygon join to Census
places, the vendor tagging, the denominators and the documentation. The method and its known limits are under "About this dataset" above.


RIGHTS POSTURE
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HOLD for commercial licensing. FREE to download.

This is not a rights problem, and it is a different situation from the other HOLD releases in
the catalogue. Nothing here is encumbered by a disputed claim. The reader locations come from
OpenStreetMap under the Open Database License 1.0, which is share-alike: section 4.4
requires that any Derivative Database made publicly available be offered under ODbL as well.
That is incompatible with selling this release on the proprietary terms the rest of the
catalogue uses, so it is not sold at all.

Share-alike cuts the other way too. Publishing the derived database openly is the licence
working as intended rather than a concession, which is why this release is in the free tier.


UPSTREAM SOURCES
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| Source | Publisher | License |
|---|---|---|
| Automated license plate reader locations tagged in OpenStreetMap <https://www.openstreetmap.org/copyright> | OpenStreetMap contributors, surveyed via the DeFlock project | Open Database License (ODbL) 1.0 <https://opendatacommons.org/licenses/odbl/1-0/> |
| Population Estimates, place within county (summary level 157) | US Census Bureau | US government work |
| TIGERweb incorporated-place boundaries | US Census Bureau | US government work |


WHAT YOU MUST DO
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Attribution alone does not discharge ODbL. If you publicly use a database derived from this
one, you must offer that derived database under ODbL as well.

Credit both parties:

    Contains information from OpenStreetMap, made available under ODbL 1.0.
    (c) OpenStreetMap contributors. Data processing: The Basin (basin.la).

The Census population and area figures carry no additional restriction.


WHAT THIS IS NOT
----------------

- It is not a register of license plate readers. No such public register exists.
- Every count is a floor. A city's number is what volunteers have found, not what is there.
- Coverage is uneven between cities and the unevenness is not random, so a comparison of two
  cities carries more risk than the headline totals do.
- A mapped reader is an observed location, not a verified working camera.

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LICENCE
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This release is derived from OpenStreetMap and is therefore offered under the
Open Database License (ODbL) 1.0, not under The Basin's usual terms.

    Contains information from OpenStreetMap, which is made available under the
    Open Database License (ODbL) 1.0.
    https://opendatacommons.org/licenses/odbl/1-0/

Reader locations were surveyed and tagged by OpenStreetMap contributors, many of
them organised through the DeFlock project.
    (c) OpenStreetMap contributors, ODbL 1.0

ODbL is share-alike, not attribution-only. If you publicly use a database derived
from this one, section 4.4 requires you to offer that derived database under ODbL
as well. Attribution on its own does not discharge that obligation.

Census population and land-area figures are US government works and carry no
additional restriction.

Cleaning, the city join and the documentation are by The Basin (basin.la) and are
released here under the same terms. Please credit The Basin alongside
OpenStreetMap when you use it.

No warranty. The full method and the known limits are available on request:
data@basin.la

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The Basin  ·  basin.la  ·  data@basin.la
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