When many different emergency teams (like police, fire, and health) work at the same big accident site, what special Incident Command System (ICS) rule helps them all make decisions together as one team?

The special Incident Command System (ICS) rule that helps many different emergency teams make decisions together as one team at a big accident site is called Unified Command. ICS is a standardized, on-scene management system designed for all-hazards incidents, enabling effective and efficient management by integrating personnel, equipment, and procedures within a common organizational structure. Unified Command is an application of ICS used when an incident involves multiple agencies or jurisdictions that each have legal, geographical, or functional authority and responsibility. Instead of a single Incident Commander overseeing the entire operation, Unified Command brings together the designated Incident Commanders from each primary agency or jurisdiction involved. For instance, at a large-scale hazardous materials incident on a highway, there might be an Incident Commander from the state police, another from the local fire department, and one from the environmental protection agency. These Incident Commanders work collaboratively to establish a common set of incident objectives, which are the specific goals they aim to achieve during the response. Based on these shared objectives, they then jointly develop a single, integrated Incident Action Plan. This plan outlines the strategies and tactics to be used, assigning tasks and resources across all participating agencies. While each agency maintains its independent authority over its own personnel and resources, all strategic and tactical decisions regarding the overall incident are made jointly by the Unified Command members. This collaborative decision-making process ensures that all response efforts are coordinated, resources are optimized, and all agencies work cohesively towards common goals, effectively operating as one team.