Some FDs use a cross staffing concept, where personnel staff either an engine or an aid car. These departments will usually do BLS transports. For decades these transports were done free of charge, although this is gradually changing. Other departments staff engines, and don't have cross staffed aid cars. These departments will have private ambulances do BLS transports exclusively.
There could be a situation where there's an aid car or engine, medic, and private ambulance on the same call. The medics are dispatched only to the most serious calls, so this is rare, but it'll happen. Usually, though, private ambulances aren't sent to calls until somebody on the scene determines that there's a need for transport to the hospital.
There could be a situation where there's an aid car or engine, medic, and private ambulance on the same call. The medics are dispatched only to the most serious calls, so this is rare, but it'll happen. Usually, though, private ambulances aren't sent to calls until somebody on the scene determines that there's a need for transport to the hospital.