ISRAELIS know all too well the need for first aid—and the difficulties of providing it. When Eli Beer was four, in 1978, he saw the carnage after a hijacked bus exploded. In 2001 he was knocked to the ground by a secondary bomb intended to kill first-aiders rushing to the scene of a suicide blast.

Conventional ambulances called to such scenes have plenty of fancy equipment, but they start from a central location and often struggle to squeeze through traffic jams. So they often arrive too late: the most gravely injured often die in minutes.

Mr Beer has designed something better. His charity, United Hatzalah, co-ordinates a group of 1,700 volunteers scattered around Israel. All are trained in basic first aid. And each has a GPS-enabled smartphone revealing exactly where he or she is.

Anyone who sees an emergency can call a central number (1221 in Israel). A smartphone app (a small programme installed on a modern mobile phone) instantly alerts the nearest first aider, who may be only a block away, standing behind a deli counter or dozing in a meeting. He stops whatever he is doing, races to the scene and tries to stop the victim's bleeding or start his heart (most volunteers are equipped with defibrillators). They mostly have motorbikes too, to nip through the traffic. When the ambulance arrives, the volunteer goes back to his day job.

Last year United Hatzalah answered 200,000 calls, saving (it reckons) thousands of lives. If he can raise annual donations from $5m today to $7m, Mr Beer will aim to respond to nearly any emergency call in Israel in 90 seconds. Soon, members of the public will be able to download an app that puts them directly in touch with the nearest first-aider, bypassing the call centre.

The model—of dispersed volunteers using ubiquitous gadgets, a simple medical kit and a motorbike—is easily exportable. A similar (but smaller) scheme has started in São Paulo. Mark Gerson, a successful New York-based businessman who chairs United Hatzalah's board, says it is his dream to spread the ingenious and low-cost idea far, wide and fast.