Photo by Peter Bischoff/Getty Images

Ambulances in Stockholm, Sweden will soon be able to interrupt in-car music to make sure motorists are always aware an emergency vehicle is nearby.

The system transmits a radio signal from the emergency vehicle to nearby FM tuners equipped with Radio Data Systems, which can forcibly interrupt audio being played from CD, Bluetooth or radio using the car stereo. This signal is sent along with a text message that displays on the dashboard tuner.


As long as the tuner is turned on, both a voice and text message will be broadcast through the car’s speakers. The hope is the system will reduce the number of drivers who are not aware an emergency vehicle is nearby. “Often drivers have only a few seconds to react and give way to emergency vehicles,” said Mikael Erneberg, who studies industrial engineering at KTH Royal Institute of Technology in Stockholm and worked on the project. “The optimal warning time is at least 10 to 15 seconds.”

Improved sound insulation in vehicles combined with some motorists playing audio at very loud volumes can make some people totally unaware an emergency vehicle is nearby. The Swedish capital will begin testing the system with a limited number of emergency vehicles over the next two months.

The early-warning system also adapts based on the speed of local traffic at the time, ensuring that a message is sent in advance to give motorists time to react. On a highway, for example, the signal would be broadcast earlier than in congested city traffic.

The team that developed the technology predicts it will reach two-thirds of all vehicles on the road in Stockholm when it is rolled-out in full.