When people tell you not to play music at full blast in your car, they're not necessarily raining on your parade -- there's a real concern that you might not hear an emergency vehicle until the last moment. You might not have to worry quite so much if a Swedish experiment proves successful, though. Ambulances in Stockholm are testing a KTH-made system (EVAM) that interrupts in-car audio with a voice warning when they're close by and responding to a crisis. The only requirement is that your car's FM tuner support the Radio Data System format, which is common in the cars you see on the road. The interruptions are speed-sensitive, too, so you'll get notices at greater distances when you're on the highway.