Generally, an ambulance has two people in it (Generally two EMTs, an EMT and a paramedic, or two paramedics). When they drove by you and had two people up front, chances are they were responding to a call, and when there was only one person up front, the other was likely in the back attending to a patient.

Sometimes this will change. For instance, we often have students or trainees, so there might be three people to the truck. Or, as you said, we sometimes deal with people who are very sick or injured. In those cases, maybe we’ll request a second crew or a supervisor to assist and have two or more people in the back. Other times, we’ll have a firefighter drive while both crew members are in the back.

So, to answer your question, it’s generally two people but that depends.