What does 10-39 mean?

The 10-39 code is used in law enforcement to indicate "Urgent use lights and siren." This means that the officer or unit should proceed with heightened urgency, requiring the activation of lights and sirens to respond quickly to a situation that demands immediate attention. In practice, this can involve responding to an emergency call or a critical incident where speed is necessary to ensure safety or the successful resolution of the situation.

The other codes listed serve different purposes and do not relate to the command for urgent response. For example, "Correct time" is used for requesting or providing the accurate time, while "Emergency situation" is a broader description that doesn't specify the need for urgent action. "Robbery in progress" describes a specific crime scenario and does not imply an urgent response in terms of using lights and sirens. Thus, the designation of 10-39 is clearly defined and focused on urgent and immediate response protocols within law enforcement operations.