Vehicle Safety indicator

My idea is to have some sort of safety indicator on the dash cluster to alert the driver of emergency vehicles sirens. The idea came to me because as the technology gets more high tech for soundproofing of road noise its harder to hear sirens around you. Which leads to more civilians get into accidents with the emergency vehicles. The indicator would light up or flash when it picks up the siren sound at a certain des able, by one or two microphones placed on the out side of the vehicle.