In APCO, Association of Public-Safety Communications Officials 10-codes, 10-77 means "Estimated Time of Arrival" or "ETA". It is used by officers, dispatchers, and units to communicate how long it will take to reach a location, allowing dispatch and other units to coordinate response times and manage resources effectively.
Here’s how it might be used in a real-world scenario:
- Officer: "Dispatch, unit 5, 10-77 approximately 5 minutes to 789 Oak Street."
- Dispatch: "10-4, unit 5, advise if ETA changes or en route status updates."
In this exchange, the officer provides an estimated arrival time to the incident location. Using 10-77 ensures dispatch and other units are aware of resource timing, which improves coordination and allows for staging or rerouting additional units if needed.
Operational Purpose
10-77 is critical for situational awareness, resource management, and timely response. By reporting ETA, officers help dispatch prioritize calls, coordinate multiple units, and maintain an organized response, especially during emergencies requiring simultaneous attention at multiple locations.
This code is commonly used for responses such as:
- Emergencies including fires, medical incidents, or accidents
- Routine patrols requiring arrival at a designated location
- Assistance calls or backup requests
- Traffic or roadway hazard responses
Officer Safety And Coordination
Providing a 10-77 update ensures all units and dispatch maintain awareness of who is arriving and when. Units may coordinate location using 10-20, acknowledge instructions with 10-4, or indicate en route status using 10-76. Accurate ETA reporting helps prevent response overlaps, resource gaps, or miscommunication during dynamic situations.
Variations And Agency Practices
Some agencies may require periodic 10-77 updates if travel time is extended due to traffic, hazards, or unforeseen delays. Local protocols often define acceptable ETA ranges, frequency of updates, and when adjustments should be communicated to dispatch or other units.
Plain-Language Alternatives
Agencies emphasizing plain-language communication may replace 10-77 with phrases such as:
- "ETA 5 minutes to location."
- "Expected arrival in approximately 10 minutes."
- "Responding, arrival estimated shortly."
Related 10-Codes
Codes commonly associated with 10-77 include 10-4 (acknowledgment), 10-20 (location), 10-23 (arrived on scene/standby), 10-76 (en route/responding), and 10-74 (assist/backup requested). Together, these codes support coordinated, safe, and efficient response operations.