IF HEADS don't roll now -- after the latest horror story of ineptitude in this city's emergency ambulance service -- the Barry administration has no sense of essential municipal services at all. Once again, a call to 911 has set off a series of blunders followed by a death. This time, an ambulance crew left a fire station without knowing exactly where it was going, failed to read a city map, drove to two wrong locations, was not monitored by an emergency dispatcher and took 40 minutes to arrive at a man's home. Nothing in this string of mistakes is excusable and -- worse still -- nothing in this string of mistakes is unprecedented.

Officials have reportedly been meeting to figure out what happened -- or didn't happen. But this has been occurring off and on since 1986. Consider the words of D.C. Council member John Wilson nearly a year ago, when he addressed Fire Chief Theodore A. Coleman at a hearing: "Chief, something has got to be done. We can keep belaboring it {but} it is grossly embarrassing. It's time to get it together, Chief. I don't think there are any more excuses I care to offer for the service, and . . . I don't think you should offer any more excuses for the service. . . ."

Yes, everybody knows that there are more than a million calls to 911 every year, that too many of them are not emergency calls and that training may not always be perfect. All of this was said before -- and still calamities occur.

Get maps. Get computers. Get people who won't be allowed on a crew until they can find their way out of a station, around a corner and on to wherever it is they're supposed to be. And keep them in contact with dispatchers, emergency rooms and whatever else the very best systems in the country insist upon.