Directional, Modulated Sirens for Improved Emergency Vehicle Signalling and Public Acoustic Safety

This concept note outlines a proposed directional siren system for emergency vehicles, using front- and rear-mounted horns with artificial Doppler shifts and speed-responsive modulation. The aim is to improve localisation, reduce noise pollution, and enhance acoustic safety in urban environments. Drawing from psychoacoustics, bioacoustic strategies, and existing DSP technologies, the system provides spatial cues without increasing volume. The concept is offered as a public, non-commercial contribution to inform future design and regulatory discussions.