Automated license plate readers are mounted across San Jose and photograph passing vehicles. After a hit-and-run, the obvious question is whether one of them caught the car that left. The answer is more restricted than most people expect, and the part that decides your case is not access — it is timing.
An automated license plate reader, or ALPR, is a camera that photographs vehicles as they pass and uses optical character recognition to read the plate. Each read is stored with a timestamp and a location. Fixed units sit on poles at intersections and along arterials; mobile units are mounted on patrol vehicles. Hundreds of California law enforcement agencies operate them, and private operators run them at commercial properties as well.
For a hit-and-run this sounds decisive. The driver is gone, the plate is the entire case, and a camera may well have recorded it. That instinct is right. What follows is what the law actually permits.
California regulates ALPR data under Title 1.81.23 of the Civil Code, added by SB 34 in 2015. The provision that governs access is Cal. Civ. Code section 1798.90.55(b): a public agency shall not sell, share, or transfer ALPR information, except to another public agency, and only as otherwise permitted by law.
That restriction is not limited to informal requests. In published guidance, the California Department of Justice has advised agencies that when responding to a Public Records Act request or to compulsory process in litigation seeking ALPR information, they should consider all applicable privileges and exemptions, bearing in mind the command in section 1798.90.55(b).
The practical consequence is straightforward. A private individual generally cannot obtain ALPR data directly — not through a public records request, and not reliably through a civil subpoena. The statute permits transfer between public agencies. It does not contemplate release to the person a vehicle hit.
Section 1798.90.55 also creates a private right of action for a person harmed by a violation of these provisions. That is a claim about misuse of the data, and it is separate from anything to do with a collision. It is being litigated in California right now, and it is not the subject of this page.
The responding law enforcement agency can query its own ALPR system as part of its own investigation. That is the realistic path for a hit-and-run victim: not personal access to the data, but a police investigation that uses it.
Which turns the whole question into one of speed. An agency can only search records that still exist, and it can only search a time and place if you gave it one.
ALPR records do not persist indefinitely. Retention varies by agency, by system and by contract, and it is short.
| Operator | Retention | Source |
|---|---|---|
| California Highway Patrol | Not more than 60 days, unless the data is being used as evidence or for the investigation of felonies | Statutory, cited in the SB 34 legislative digest |
| Local police and sheriff agencies | Set by each agency's published ALPR usage and privacy policy. Frequently shorter than 60 days. | Agency policy, required to be published under SB 34 |
| Private operators | Set by contract and by the operator's own posted ALPR privacy policy | Operator policy |
Do not rely on a single number. Ask the responding agency what its retention period is for its own system. SB 34 requires each operator to publish a usage and privacy policy, so the figure is obtainable.
What actually determines whether an ALPR search is possible at all.
City streets in San Jose go to the San Jose Police Department; freeways and state routes go to the California Highway Patrol. Reporting today rather than next week is the single largest factor in whether any camera record still exists when someone looks.
An ALPR search runs against a place and a time window. “Somewhere on Story Road Tuesday evening” is not searchable. The nearest cross streets, the direction the vehicle was heading and the time to within a few minutes are what make a query possible.
Colour, body style, make if you saw it, any partial plate, damage, decals. A partial plate combined with a time and a location is often enough to narrow a search that a full description alone would not.
Hit-and-run involving injury is addressed by Cal. Veh. Code section 20001; property damage only by section 20002. Classification affects how a case is investigated, and under the CHP retention rule, data being used as evidence or for a felony investigation is not subject to the ordinary 60-day limit.
Ask the investigating officer directly whether an ALPR query is possible for that time and location, and put the request in writing so there is a record of when you asked. A written follow-up within the first week costs nothing and is worth having.
Photograph the damage to your vehicle before repair, keep dashcam footage, and note every nearby business that might have a camera facing the street. Private surveillance footage is commonly overwritten within 72 hours unless someone asks the owner to hold it.
ALPR data is one of several records that disappear on their own schedule after a collision. Business and traffic camera footage is routinely overwritten within days unless a preservation request is sent. Vehicle event data recorder information stays in the car until it is downloaded and is gone once the vehicle is repaired or sold for salvage. Independent witnesses move and stop answering their phones.
None of this is recoverable later. The window in which a hit-and-run claim can be built is measured in days, while the window in which it can be filed is measured in years. Those are two different clocks and only one of them is forgiving.
A hit-and-run claim does not necessarily end when the driver is not found. Uninsured motorist coverage under Cal. Ins. Code section 11580.2 is written to respond in exactly this situation, and it is frequently the only coverage available after an unidentified driver leaves the scene. Checking your own declarations page is worth doing on day one rather than after the investigation stalls.
The general California deadline for a personal injury lawsuit is two years from the date of injury under Cal. Code Civ. Proc. section 335.1. If a public entity is involved — a city vehicle, a dangerous roadway condition — an administrative claim is required within six months under Cal. Gov. Code section 911.2. Property damage runs three years under section 338. A criminal hit-and-run investigation running in parallel does not pause any of these.
Every category of camera evidence discussed on this page shares one property: it disappears on a schedule nobody announces. Private business systems commonly overwrite within days. Residential doorbell cameras retain footage only as long as the subscription tier allows. Municipal and agency systems follow their own retention policies.
The practical consequence is that a request made in week one and the identical request made in month two produce completely different outcomes. In the second case the footage is simply gone, and no legal process recovers it.
Identify every camera with a possible view of the scene as soon as you are able, note the business or address, and put a preservation request in writing immediately.
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