It wouldn't be even RFID, the emergency services vehicle would have a low power short range transmitter, and a receiver in the car that would respond to it.

I saw this before but didn't comment - I know what you mean exactly. I rode up front in an ambulance when a friend was injured and it only clarified my fears - you think it is bad in your car, imagine what it is like driving the EMS vehicle. It is nerve wracking. In the ambulance it was like no one even knew we were there hardly. And I know what you mean about being in your own vehicle too - I like rock music at excessive levels and listen to CD's also. I was thinking of the Mister Mic concept when I first was thinking about it, where they output at super high gain local band FM and it either broadcasts a message over your radio. That day in the ambulance I actually discussed it with the driver on the way inbetween near misses and he really liked it and was enthusiastic. I must say though, I have a Cobra radar detector and it can listen for EMS vehicles with the special broadcast units on them. In my area, Dallas, Tx, the Dallas FD doesn't have them but the wealthy suburb of Plano does, so in Plano when an EMS vehicle is within about 200 yards of me this thing goes off with a special tone. The problem is only 10-20 percent of EMS units nationwide are equipped with the notifier part of it. My only complaint is I have had ambulances get within about 200 feet of me or less before it went off. This thing also does Trains also which is nice, but again, only about half of the trains I encounter are equipped with the notifier. You are on the right track though - it is urgently important that something be done for the sake of citizens and EMS personnel. SS