While it may be nice to have a car that's well-insulated against traffic noise and that has a good stereo, those qualities can be detrimental when it comes to hearing the sirens of emergency response vehicles. Fortunately, however, a team of students from Sweden's KTH Royal Institute of Technology have developed a work-around. They've created a system in which drivers' stereos actually alert them to the presence of approaching ambulances.

Known as the EVAM System, the technology allows ambulances to transmit an FM radio signal to vehicles on the road in front of them. The faster that the traffic is moving, the farther ahead it's transmitted.

In the case of cars with relatively modern stereos, that signal will be picked up by those vehicles' existing Radio Data System (RDS). This will cause the current audio playback to be interrupted – be it from radio, CD, or any other source – with a voice announcement that an emergency response vehicle is approaching. A corresponding text message will also appear on the stereo's tuner display.

Although not all vehicles will have RDS, or will have their stereos turned on, it is estimated that the EVAM System should be able to alert approximately two thirds of the cars on Swedish roads.

Plans call for a pilot project to begin in the first quarter of this year, with select ambulances in the city of Stockholm.