Here in Washington, DC, fire engines are always the first-responders to an ambulance call. The theory being that there are more fire crews than ambulance crews, so the firefighters can get there more quickly and start CPR if necessary. Also, the trucks come in handy for blocking traffic, and the rest of the crew can be useful in moving the patient. On the other hand, the wear-and-tear on half-million-dollar fire engines must be a considerable drain on the budget. I've often thought that maintaining a smaller vehicle and sending just a couple firefighters as first-responders would make sense, but I guess they want to keep the crew and their fire engine together in case they have to respond to a fire once they're no longer needed at the current emergency. For the same reason, you often see manned fire engines parked outside of grocery stores. The whole group have to go along grocery shopping, with some sticking with the engine while others shop.