Command units can be found at any major incident. Whether the emergency involves a natural disaster, fire or hazardous material, a command unit provides a central point of control and communications for those at the scene.

Although most departments still establish the initial incident command on the ground or from the back of a small command vehicle, many departments have found there are advantages to having a dedicated command unit take over some of the more critical functions. To understand these advantages, one must understand how and why departments use these vehicles.

Most modern fire departments find themselves responding to fewer structure fires. On a daily basis, they may handle emergency medical calls, vehicle accidents, specialized rescues, hazmat releases, wildland-urban interface fires, evacuations, explosions and more. Add responses to deal with the aftermath of various natural disasters, and there's a need to establish command at many different types of emergency situations.

In the past, some departments specified small command areas built into their pumpers, rescues or hazmat units. While this approach may work for departments that respond to only a single type of major incident, it can be awkward for other situations. For example, using a rescue with a built-in command area at a hazmat incident may mean the unit has to remain in one location at the scene for an extended period. In that situation, the vehicle can't be repositioned to take advantage of its rescue capabilities or respond to other rescue incidents, effectively taking it out of service. Having a single command unit designed to handle all types of incidents can free other apparatus and personnel to handle their specific functions more effectively.

Another reason departments use dedicated command units is to accommodate the many different types of communication equipment needed at major incidents. In addition to the wide range of radio frequencies used for interoperability, departments often have to communicate through landline and cellular telephones, as well as send and receive information via satellite links and closed circuit television. With proper equipment, command units also can act as repeater stations for communications between handheld radio units.

At large-scale, long-term incidents, command units can provide a base of operations for trained specialists and dispatchers to handle all communications and resource assignments relating to the incident without interfering with the normal, everyday traffic for the rest of the area. Most command units have two or more built-in workstations with communications gear, desktop surfaces, chairs, computers and other equipment. Some units have slide-out wall sections that can significantly expand the interior space without increasing the travel width or length of the vehicle.

Having an enclosed command area also allows incident commanders to work in a quiet, secure area where they can assess the ongoing situation and develop action plans. With ready access to communications, weather data and other information, they can work more effectively inside than they could outside amid the noise and confusion of the emergency scene. To facilitate discussions with personnel outside the unit, but avoid unnecessary traffic in and out of the command and communications areas, some departments specify a drop-down awning and external telephone connections built into the side of the body.

Most large fire departments already have one or more command units on their apparatus rosters, but there are an even greater number of mid-sized departments that could use one. For them, the cost of a well-equipped mobile command and communications vehicle is simply beyond their budgets.

One of the most common solutions to this problem is for fire departments to join with other departments within their own city or region to purchase a single unit that responds to a variety of calls. For example, some fire departments pool their budgets with their local law enforcement agencies to specify and operate a joint-agency command vehicle. Other departments join with the municipal office of emergency services or the department of public works to buy a command unit. The most common solution is for several departments within a region to buy a single command unit and station it at a central location. One department, usually the largest one and where the unit is stationed, maintains the unit and provides a crew for the initial response. The other departments contribute to the expense of the upkeep and provide additional trained personnel to operate the unit as required.

This joint-use solution makes sense for many reasons. First, various agencies within a city or region usually have to coordinate their efforts at major incidents anyway. Having a single, centralized command unit can make that job easier. Second, much of the command and communications equipment required by one department or agency is the same as the equipment required by another, so it is often more cost effective to specify one well-equipped unit that can handle it all. Finally, from a practical standpoint, it is better to have a single command center at a crowded incident scene, than it is to have two or three units responding and taking up room or having to be positioned in different locations.

Whether departments decide to operate their own command unit or pool their budgets and personnel to operate an one-for-all unit, having a well-equipped command and communications vehicle on the scene can be a big help for a wide variety of emergency situations.