5-09/550.30 - Field Protocols - Patrol



Automated License Plate Recognition (ALPR) is useful in general patrol assignments when the patrol vehicle is in a position to monitor vehicular traffic.

ALPR-equipped vehicles should be deployed regularly.  When not in use, ALPR-equipped vehicles shall be secured.

Personnel shall perform an upload of hotlist data prior to the deployment of an ALPR system to prevent potential traffic stops using outdated hotlist information.

When the ALPR system indicates a hit, prior to making the traffic stop and when safe to do so, personnel shall:

  • Verify that the license plate information matches the license plate image of the vehicle.
  • Confirm that the hit is still “active” by either running the license plate through the vehicle’s Mobile Digital Computer (MDC) or via their radio to dispatch (if confirming via SCC, advise the request is for an ALPR hit on a vehicle).
  • If a decision is made to initiate a “Code-9” due to an ALPR hit on a stolen vehicle and prior to receiving a secondary confirmation, the deputy shall advise SCC they are following a vehicle due to an ALPR stolen vehicle hit.  

Proactive/manual entry of ALPR hotlist in the field is permitted for:

  • Dispatched reports of crimes, “Be on the Look Outs” (BOLOs), Amber, Blue, Silver, or Yellow Alerts, or other law enforcement alerts in which a license plate number is part of the broadcast.
  • When directed or authorized by the unit commander for a legitimate law enforcement purpose.
  • Department members should query their ALPR system to ascertain if there is a prior read of the license plate which is the subject of the particular alert, bulletin, or alarm.

Proactive/manual entry of ALPR hotlist in the field is required for Amber Alerts, missing child, or critical missing persons.  Additionally, Department members must query their ALPR system to ascertain if there is a prior scan or read of the license plate which is the subject of the alert.

ALPR may be used in special operations or details such as:

  • High crime area patrols;
  • Gang investigation/suppression;
  • Driving under the influence initiatives;
  • Enforcement details;
  • Directed criminal investigations;
  • Other investigations subject to authorization from the investigating unit’s unit commander.

When a violent crime occurs, the Department may solicit assistance from other law enforcement agencies with ALPR-equipped vehicles to assist in identifying potential vehicle license plates and/or to gather license plate data in a particular area.  Similarly, other law enforcement agencies may request assistance from this Department in the event of the same.  Any mutual aid request shall be directed through the station’s operations staff.  Consideration should be given to deploying ALPR strategically, such as at a perimeter, choke points, major highway, or other avenues of approach or escape. 

Personnel shall log that they are using a mobile ALPR system in their Mobile Digital Computer (MDC) worksheet when logging on. 

  • Deputies shall ensure that logs and arrests associated with the ALPR system are complete and utilize the appropriate ALPR statistical code.
  • If the deputy’s log has an arrest associated with an ALPR hit, this information will be provided to the Advanced Surveillance and Protection Unit (ASAP) to retain the information for the case file.
  • The deputy’s log will be retained until all ALPR-related arrests have reached a final disposition.

When desk personnel receive a hit from a fixed ALPR system, which is the result of license plate data taken from a fixed camera, they shall confirm the current status of the vehicle via their CAD terminal or SCC.  While waiting for confirmation, desk personnel shall advise field patrol units of the ALPR hit, the location, direction of travel, the vehicle description, request Aero Bureau, and coordinate responding field units.