Whats the difference between private ambulances and fire dept. ambulance crews (aside from who handles their payroll)?
In my current city (a suburb of Philadelphia) the fire department I volunteer with holds the license for the basic life support ambulance you ride in on the way to the hospital after calling 911, and provides the two-EMT crew in it. If you need more advanced care, such as intubation or IV medications, a single-paramedic chase vehicle is dispatched to rendezvous with the FD ambulance. This advanced life support car and the paramedic in it are hospital-based. ALS can be automatically dispatched when the 911 call center hears how severe the call will be, or the FD BLS truck can call dispatch and ask for it if a previously simple call deteriorates. This is completely different from the system I used to work for, which was also in PA, but much more rural. There, a fire department quick response pickup truck would show up and try to stabilize the patient until the private BLS service I used to work for could show up. They had no part in transport, and often had only first responder training
In addition to the above, some smaller municipalities use the private services to cover nights or weekends when the fire department is understaffed, or when the paramedic calls in sick. Likely, the majority of the private ambulance services you see will be for transporting people to and from one level of medical care or another.
Specifically to answer your question, read here and here. However, in general, like said above, 911/EMS service depends on your area. There are some rural areas where the ambulance service is all volunteer and you will usually get a volunteer EMT to respond. Mostly in Washington state EMS is run through fire districts (they generally have paramedics and EMTs) however there are some private ambulance services (Medic One and AMR in the Seattle area) that are integrated into the EMS response system. Fortunately in Seattle, our EMS system is excellent. Between Harborview, Seattle Fire, AirLift, and Medic One, the training of EMS providers and coordination of the EMS system is exceptional. For your last questions, EMS providers, if they just happen upon an accident, will usually stop if there are no other providers there, however they may be very
