FAQs

How does ALPR work in Fleet 3?

The Fleet 3 Dual-View Camera includes a dedicated 4K image sensor for ALPR image capture and Axon’s AI-enabled plate-reading software. The 60° field of view camera reads plates across three lanes out to 50 feet in front of the vehicle and passes those reads to the hub. Plate reads are compared to lists of plates of interest (hotlists) and matches generate alerts that display on the Fleet Dashboard application for officer disposition. Plate reads and hits are encrypted, stored on the hub, and securely uploaded to CJIS certified cloud storage.

How do I enable Fleet 3 ALPR?

ALPR is a subscription service activated by an Axon Evidence administrator. No additional equipment is required. If the subscription is activated on initial deployment, the service will be immediately enabled. If subscription is activated after Fleet 3 initial deployment, it will become available in each vehicle within 10 minutes. Vehicles must be connected to Axon Evidence.

Can I use ALPR independent of Fleet 3 system/cameras?

No, ALPR is only available in the Fleet 3 in-car video system.

How do I turn on ALPR in the vehicle?

Once enabled, Fleet 3 ALPR will activate automatically when Fleet 3 powers on.

How do I turn ALPR off?

Unless your agency terminates its subscription, ALPR is functioning whenever Fleet 3 is powered on. Even if Fleet Dashboard is not running or the MDT is off, ALPR will function and the Dual-View camera will still produce audible alerts.

Fleet Dashboard settings let you suspend hotlist alerts, during which reads and hits are still collected but alerts, with the exception of those defined by your agency as “High Priority”, are suspended.

How are High priority alerts defined?

Your admin defines your agency's alert priorities in Axon Evidence when they create the hotlist.

What configuration options does ALPR have?

In the vehicle – Use Axon Fleet Dashboard to mute alerts, which suspends low and normal priority alerts (high priority alerts remain active).
In the office – Your admin defines which offense categories will generate alerts and assign priorities: high, normal, or low.
In Axon Evidence: The Fleet 3 Hub will sync hotlist alert configurations within five minutes of configurations being saved in Axon Evidence, assuming the hub is powered on and connected to Axon Evidence.

How well does ALPR perform compared to legacy systems?

Legacy ALPR systems rely on camera technology that was initially developed for fixed ALPR applications. The typical ALPR camera focuses on one lane of travel, with a very narrow field of view and very specific focal length, yielding a capture area that is approximately 4x4x6 feet. Plates must pass through this small capture area to be read.

In fixed applications, this works quite well, but when mounted to a mobile application, the capture area is not static, so many plates simply do not pass through the read area and are never read. To counter this, these systems may employ multiple cameras.

Conversely, Axon Fleet 3 ALPR uses a wide 60° field of view covering three lanes out to 50 feet away. While a legacy ALPR system with two forward facing cameras has a detection area of approximately 192 cu. feet, ALPR's detection area is nearly 90 times greater.

ALPR is not active IR illuminated like traditional ALPR systems. Plate capture is dependent on sufficient illumination. In low light/night conditions, the capture area is limited to the headlight illuminated area within the 3 lanes in front of the vehicle: everything the light touches. Generally, if you cannot read the plate with your eyes, the camera can't either.

How accurate is ALPR?

ALPR read accuracy is equal to or greater than 90% in all conditions.

What happens when I get a false positive alert?

Each hit alert lets you quickly identify the alert as correct or incorrect based on the plate read text comparison to the plate image and the plate state comparison to the hotlist state of origin. If either is incorrect, simply select Incorrect or Wrong State/Province in the alert window to close the alert. In addition, if the false positive is related to a plate that has not yet been removed from the hotlist, use the suspend alerts feature to prevent additional alerts.

How fast does the hit alert happen after the plate read?

ALPR will alert within one second after the plate is read to assist in a fast response even in high closing speed scenarios.

How can I help improve ALPR capability in my area?

Sign up for the Axon Customer Experience Improvement Program (ACEIP) at the Tier 1 level. This data sharing agreement lets us use anonymized data collected by your agency to support continuous product improvements. The data includes the plate crop and metadata such as date, time, and read confidence score. Axon does not collect GPS location, hotlist information, or any agency input into the record, other than correct/incorrect determination. For details, see https://www.axon.com/aceip.

What is ALPR low-light performance and how does this compare to the dedicated ALPR system my agency already has?

The Dual-View camera is mounted behind the windshield and is not IR-illuminated. It will read plates in low light conditions if the plates are sufficiently illuminated by ambient light sources or headlights. Fleet 3 will generally not read plates in total darkness. In low light or nighttime conditions, license plates illuminated by headlights can be detected and read accurately.

How is installation of Fleet 3 ALPR different than traditional ALPR systems?

ALPR is embedded into Fleet 3. There is no additional installation effort required to enable ALPR. No additional equipment, no holes to drill, no additional external mounting hardware or cables, and no complicated camera aiming/calibration process.

How does ALPR work with other technology in the car, like CAD and ICV?

ALPR is integrated with the Fleet 3 in-car video evidence system and shares a common application (Fleet Dashboard) that runs on an MDC or mobile device. Move easily between ALPR and in-car video work-flows within the Fleet Dashboard application on your device. Video evidence and ALPR read/hit records upload to Axon Evidence. Once an alert is detected and confirmed correct, ALPR automatically copies the plate number to the clipboard for easy pasting into the CAD application.

How does the environment affect ALPR performance?

Unlike traditional ALPR systems, the Fleet 3 front camera is inside the vehicle and behind the windshield, protected from harsh weather conditions with the exception of extreme temperatures (heat/cold). Operational temperature range is -40 ⁰C to +85 ⁰C.

ALPR performance, much like driving visibility, is degraded by heavy precipitation (rain/snow) or fog. The camera must be able to see plates clearly enough to read them.

Accumulation of precipitation on the windshield (rain or snow) that obstructs or partially obstructs the camera's clear view will degrade performance. The degree of performance degradation is positively correlated to the severity of the precipitation.
An advantage of Fleet 3 ALPR over traditional systems is the benefit of the vehicles windshield wipers to clear accumulations of precipitation from the camera's view. Traditional, externally mounted systems have no built in windshield wiper or other device to keep the camera view clear.
Fog will also degrade performance. Unlike precipitation, windshield wipers provide no mitigation. The degree of performance degradation is positively correlated to the severity of the fog.

What will ALPR do if multiple hot plates are read at the same time?

All hits are saved, with the highest severity hit prioritized for alert.

What will ALPR do if I am following the same plate(s) for a while?

This is referred to as a "long track", meaning Fleet 3 maintains a track on the same plate for a period of time after the initial read. Fleet 3 will generate a sub-record of geo-position and time stamp every two minutes, which will be included in the read record. This will continue as long as the plate is not out of view of the camera for longer than 10 minutes. Records with long tracks will show a time range of detection in the record search results, indicating the vehicle was spotted either multiple times in succession or stayed in frame for an extended period of time.

For example, if a plate is read and then goes out of frame but returns nine minutes later, a subsequent read of that same plate is collected and recorded on the original read record. If that same plate goes out of frame for 11 minutes, a new record is created.

Does ALPR recognize plate state of origin and vehicle color, make, and model?

Axon Fleet 3 uses artificial intelligence (AI) to process ALPR reads and establish a range of attributes including vehicle color, make, and type to support vehicle-based investigations. However, as part of Axon's partnership with Flock Safety, ALPR customers in the U.S. can elect to use the Vehicle Characteristic feature from Flock Safety to both capture and search on these characteristics in Flock Safety.

Does ALPR require an LTE connection?

Yes. Several features rely on communication with Axon Evidence over LTE to function:

Downloading and maintaining the most current hotlist
Supporting Amber Alert, BOLO, and other high priority alert distributions
Read and hit record uploading

Basic ALPR functionality (plate reading and alerting against on-board hotlists) do not require LTE connection to be active and will continue to function even during temporary loss of LTE signal.

What happens to hit/read records?

Both read and hit records are generated in the Fleet 3 Hub and temporarily stored there before uploading. You can view the records stored in the hub on the reads and hits pages in Dashboard. Copies of read and hit records are stored on the hub for 24 hours. Both read and hit records are uploaded to Axon Evidence cloud storage where they can be searched for investigative purposes and used for evidence in a case.

If your agency has both Fleet 3 ALPR (mobile) and Flock Safety ALPR (fixed), you can establish an API connection between Axon Evidence and Flock Safety that lets you search across both Axon and Flock Safety records in Flock’s Search interface.

How long are hit/read records retained?

Hit and read record retention is agency configurable. The default retention period is 30 days, after which records are deleted and cannot be retrieved.

Flock Safety adheres to applicable laws for ALPR data retention. Contact your Flock representative if you need more information on this.

Can I search read records with ALPR?

Yes. ALPR supports record searching by full or partial plate number, vehicle, owner, category (hit/read), and date/time range.

Users with Flock integration can also search by vehicle characteristics such as plate state of origin, type/body, make, color, unique identifiers such as "roof rack". Integration also allows search by location across both Axon and Flock records.

What if retention periods for my ALPR and Flock Safety systems differ?

Records in Axon Evidence follow the retention rules of their originating system: ALPR (Axon Evidence or Flock Safety. However, a record assigned to an ongoing case in Axon Evidence will follow Axon Evidence retention rules regardless of the originating system.

What types of hotlists does ALPR support?

Axon ALPR supports any hotlist you are using today, including NCIC vehicle list, state, provincial, regional, and any lists generated by your agency. Upload hotlists in Axon Evidence or automatically via Axon API (requires PSO service to build the integration).

How are agency hotlists supported?

Axon Evidence supports creation and management of hotlists, editing expiry settings, and configuring alert categories. Agency lists are broadcast to each Fleet 3 installed vehicle and stored in the Fleet 3 Hub.

Who in my agency can create a hotlist?

This is up to your agency. Your agency's administrator can assign list creation privileges to any user in your agency.

Can we edit state and NCIC hotlists, like if we discover an incorrect record?

No, not directly. Errors must be corrected at the source. This requires a strict CJIS protocol your agency is already trained to follow.

How often are hotlists updated?

NCIC and state list update intervals are based on the respective data update intervals defined by those agencies. NCIC is four times per day (every six hours). Agency-generated lists can be updated any time in Axon Evidence and the Fleet 3 hub checks for new or updated hotlists every 30 minutes.

For high priority alerts like AMBER Alerts, BOLOs, and ATLs, Axon Evidence can quickly create a single hot record that can be immediately broadcast to all Fleet 3 installed vehicles.

Can we remove or correct a high-priority alert, such as if the plate is incorrect or the vehicle is apprehended?

Yes, Axon Evidence lets you edit and delete any agency-created hotlist.

What happens to the list if my vehicle doesn't have an active LTE connection (out of range) at the time my hotlist record is updated?

Your vehicle will update its list, including any missed changes, within 30 minutes of regaining an active data connection.

How do I identify Fleet 3 systems with out-of-date hotlists?

The hub details page in Axon Evidence identifies list status by list type, such as agency or NCIC. Go to Admin > Inventory > Vehicles:

Who has access to the read/hit record database?

Your admin will assign access privileges to hit/read records to individual users within your agency. If your agency uses Flock Safety, you can also access Axon read/hit records through their search tool. Similarly, your agency's Flock Safety admin can assign access rights to individual users in your agency. Neither Axon, Flock, nor any unauthorized third party or law enforcement agency ever has access to your agency's data.

Can I share read/hit data with other/partner law enforcement agencies?

Axon currently partners with Flock Safety for data sharing. All Fleet 3 ALPR agencies can search for both Flock and Axon records in Flock Safety Search.

Any third party willing to sign Axon’s Partner API Terms of Use may use the Search API to support third-party integrations.

Does Axon's search application require a warrant number or have other process limitations before I can search a read/hit database?

Search reason is a required field for any search and is logged and auditable. This helps ensure plate read data is accessed only for appropriate reasons. Your admin grants users search privileges per your agency's policy. This addresses some states' legal requirements for ALPR usage and is core to Axon's ethical approach to use of ALPR.

Can I save my search results?

Search results can be saved as evidence and assigned to cases. Read records saved as evidence are subject to your agency's evidence retention policy.

In what regions does ALPR work?

ALPR is currently trained to read plates within the U.S., Canada, and the UK, with constant expansion into additional international regions.