Ambulances are able to carry only a very small number of patients (generally only one or two), making it extremely complex to transport all the victims or patients that have treatment or evacuation needs when a mass casualty event or disaster occurs. Currently, when such an event occurs, many ambulances are called to transport the victims, and, given the limited number of ambulances generally available within a given geographic area, the total number of patients that can be transported is also greatly limited. Furthermore, with so many victims needing transportation from one mass casualty event, if all conventional ambulances are used for transport, people in other coverage areas might suffer because ambulances are not available to handle other emergencies.
A similar problem is encountered when an evacuation of a large number of patients is required. For example, the ability to relocate the patients from a hospital or a nursing home that may be in the path of an approaching hurricane also would be limited by the availability and number of ambulances available.
Similarly, if there is a need to treat a large number of victims at a given location, the only option available now is to transport the victims to a remote site for treatment, and movement of the large number of victims is similarly impacted by the limited number of ambulances. Alternatively, a tent-like treatment facility might be set up, but the suitability of such a system would depend on the disaster conditions (e.g., a tent would not hold up well during windy conditions; climate extremes might be difficult to control; once patients are stabilized in the tent-like structure, they would still need to be transported to a hospital or other facility for extended care).
Other ambulance-type vehicles, such as those used in the military, use J-type hooks or loop-type straps for holding stretchers, and loading a stretcher onto such a J-hook type holder or loop-type straps requires up to six people to maneuver the stretcher into storage position.
Furthermore, if there is a need to transport a large number of casualties, multiple ambulances or hearses would be needed.