Ambulances in Stockholm are to test a system that interrupts in-car audio listening to warn drivers that they need to get through.
The BBC reports that the solution – developed by students at the city’s KTH Royal Institute of Technology – uses an FM radio signal to jam drivers’ speakers, broadcasting a voice warning, and showing a text message on the radio display.
The report adds that it will only be able to alert cars that have their radios turned on, though it can also interrupt CDs and music connected via Bluetooth. It works using a radio transmission sent from the emergency vehicle to nearby FM tuners that are equipped with RDS.
“Often drivers have only a few seconds to react and give way to emergency vehicles,” Mikael Erneberg, a KTH student who worked on the system, told the BBC. “The optimal warning time is at least 10 to 15 seconds.”
The report continues by explaining how loud music can prevent sirens from being heard and, according to the students, accidents involving motorists who have not heard emergency vehicles are on the rise.
The city will begin testing the system in a limited number of ambulances and fire engines, with plans to expand across the country later this year.
The warning system can work out how far in advance messages need to be heard depending on the speed of traffic.