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Surveillance Technology Information
What is the use and purpose of the technology, such as assisting in ongoing criminal investigations, locating missing children, or locating stolen vehicles?
Automated License Plate Reader (ALPR)

ALPR may be used in conjunction with any routine patrol operation or criminal investigation. ALPR-equipped patrol cars may query captured license plate information against the DMV published lists of stolen license plates for the detection of stolen vehicles. The captured data may be used for investigative purposes when data is captured in an area later determined to be the site of criminal activity, to determine the historical location of vehicles associated with a criminal investigation, and to canvass license plates around any crime scene.

Body Worn Camera (BWC)

The purpose of the BWC is to record encounters between police personnel and the public. Law enforcement’s use of BWCs has proven effective in reducing violent confrontations and complaints against officers. BWCs provide additional documentation of police/public encounters and may be an important tool for collecting evidence and maintaining public trust.

Mobile Audio/Video (MAV)

The purpose of the MAV is to record law enforcement activity. The MAV captures audio and video of activity from the perspective of the police vehicle. The MAV has a forward facing camera and a wireless microphone. The MAV may also have a prisoner compartment camera and microphone inside the vehicle.

Who is authorized to collect or access the data collected?
Automated License Plate Reader (ALPR)

All data will be closely safeguarded and protected by both procedural and technological means. No member of this department shall operate ALPR equipment or access ALPR data without first completing department-approved training. Members who are trained and approved to access ALPR data are permitted to access the data for legitimate law enforcement purposes only, such as when the data relate to a specific criminal investigation or department-related civil or administrative action.

Body Worn Camera (BWC)

Officers shall collect BWC recordings during enforcement related contacts. Enforcement related contacts include the following: Traffic stops, field interviews, detentions, arrests, persons present at calls who are accused of crimes, and consensual encounters in which the officer is attempting to develop reasonable suspicion on the subject of the encounter.

Officers may review their own recordings. Detectives are responsible for reviewing, updating and tracking digital evidence associated with their assigned cases. Digital evidence may also be accessed for limited administrative purposes. The Commander may consider requests to review any recording and approve such requests.

Mobile Audio/Video (MAV)

The MAV automatically records footage upon the officer activating the patrol vehicle’s forward facing red light. The MAV continuously records and it will prepend approximately 20-30 seconds of footage captured prior to activation. The officer also has the ability to manually activate MAV recordings. Recordings are collected automatically upon the patrol vehicle returning to the station. The recordings are saved locally to a storage server and made available to authorized users through an online portal.

Recordings may be accessed and reviewed in any of the following situations: for use when preparing reports or statements, by a supervisor investigating a specific act of officer conduct, by a supervisor to assess officer performance, to assess proper functioning of MAV systems, by department investigators who are participating in an official investigation, by department personnel who request to review recordings, by an officer who is captured on or referenced in the video or audio data and reviews and uses such data for any purpose relating to his/her employment, by court personnel through proper process or with permission of the Chief of Police, by the media through proper process or with permission of the Chief of Police, to assess possible training value, and recordings may also be shown for training purposes.

How the system is monitored to ensure that the data are secure
Automated License Plate Reader (ALPR)

All ALPR data downloaded to the mobile workstation and in storage shall be accessible only through a login/password-protected system capable of documenting all access of information by name, date and time.

Body Worn Camera (BWC)

The BWC footage is stored in digital format on a server which is accessible to authorized personnel through a system which requires user name and password. The system has security controls which regulate who has the ability to view or export BWC footage. Audit logs document when videos are exported and require the user to document why the footage is being copied.

Mobile Audio/Video (MAV)

The BWC footage is stored in digital format on a server which is accessible to authorized personnel through a system which requires user name and password. The system has security controls which regulate who has the ability to view or export BWC footage. Audit logs document when videos are exported and require the user to document why the footage is being copied.

Who owns the surveillance technology?
Automated License Plate Reader (ALPR)

The Town of Atherton owns the hardware used to record and store ALPR information. The Town of Atherton uses software developed for the specific purpose of making the gathered data accessible to authorized users. The software is licensed to the Town of Atherton for this purpose.

Body Worn Camera (BWC)

The Town of Atherton owns the BWCs. The Town of Atherton uses software developed for the specific purpose of making the gathered data accessible to authorized users. The software is licensed to the Town of Atherton for this purpose.

Mobile Audio/Video (MAV)

The Town of Atherton owns the MAV systems used to record and store the videos. The Town of Atherton uses software developed for the specific purpose of making the gathered data accessible to authorized users. The software is licensed to the Town of Atherton for this purpose.

What measures were taken to ensure the accuracy of the data?
Automated License Plate Reader (ALPR)

Upon detection of a stolen license plate or vehicle, the operator must visually confirm the automatically captured information matches the actual plate of the suspect vehicle. The ALPR system preserves a photograph of the license plate, allowing such comparison during future analysis.

Body Worn Camera (BWC)


The BWCs capture audio and video. Other data captured include the time and date watermarked on the video. Such information could be cross-checked against dispatch logs which use date and time information from a reliable source. The recording platform uses hash values to ensure recordings are not altered before or after storage on the server.

Mobile Audio/Video (MAV)

The MAV system has security features which prevent the deletion of videos without authorization. The system maintains an audit log which records the activity associated with all videos stored on the system. Security controls regulate which users can view videos and export them from the system. The recording platform uses hash values to ensure recordings are not altered before or after storage on the server.

How long the data will be retained?
Automated License Plate Reader (ALPR)

All ALPR data downloaded to the server should be stored for a minimum of one year (Government Code § 34090.6) and in accordance with the established records retention schedule. Thereafter, ALPR data should be purged unless it has become, or it is reasonable to believe it will become, evidence in a criminal or civil action or is subject to a discovery request or other lawful action to produce records. In those circumstances the applicable data should be downloaded from the server onto portable media and booked into evidence.

Body Worn Camera (BWC)

All BWC data downloaded to the server should be stored for a minimum of one year (Government Code § 34090.6) and in accordance with the established records retention schedule. Thereafter, BWC data should be purged unless it has become, or it is reasonable to believe it will become, evidence in a criminal or civil action or is subject to a discovery request or other lawful action to produce records. In those circumstances the applicable data should be downloaded from the server onto portable media and booked into evidence.

Mobile Audio/Video (MAV)

All MAV data downloaded to the server should be stored for a minimum of one year (Government Code § 34090.6) and in accordance with the established records retention schedule. Thereafter, MAV data should be purged unless it has become, or it is reasonable to believe it will become, evidence in a criminal or civil action or is subject to a discovery request or other lawful action to produce records. In those circumstances the applicable data should be downloaded from the server onto portable media and booked into evidence.