The Emergency something car, is a first response advanced life support unit. It's equipped with paramedics and most of the same equipment as an ambulance and get to the patient first and evaluate/stabilize/initiate treatment. When the ambulance gets there they transfer patient care and/or continue to assist during transport, depending on the patient's condition. It decreases the number of transport capable units needed and in the case of smaller vehicles decreases response time. Our fire department does the same thing with fire engines, some use SUVs and I believe parts of the UK use/used motorcycles.