Every year, tens of thousands of fire engines, ambulances, and police vehicles collide with other vehicles driving in front of them or crossing at intersections. A world-wide accounting was not found in the literature, but in the United States the frequency, causes, and remedies are published by the National Highway Traffic Safety Administration and others.
The results are death, injury, and property damage followed by long lasting effects on society, such as psychological trauma in families, court battles, insurance issues, and debates by elected officials.
One of the foremost causes is drivers not hearing sirens because the 80-90 dBa loudness imposed to protect the hearing of pedestrians is too low to be heard over wind noise at 60 mph highway speeds and the 150 ft effective range in city traffic is so short drivers have little time at 30 mph speeds to react.
The authors propose to reduce the number of these collisions by supplementing the sound emitted from the emergency vehicle siren with sounds from “Virtual Sirens” at other locations farther up the street.
The Virtual Siren package includes an antenna, a radio frequency (RF) receiver, processer circuitry, a loudspeaker, programmable software , and a library of optional siren sounds (whine, beep, whoop, etc.) used throughout the world.
Sounds from all Virtual Sirens up to 1000 ft in front of the emergency vehicle are simultaneously triggered when the emergency vehicle emits an RF signal from the FHSS (Frequency Hopping Spread Spectrum) transmitter signals traffic lights in it’s path to change the color before arrival at the intersection. After passing, the Virtual Sirens will automatically turn off.
Immediate uses by local governments world wide are envisioned for two different styles of packaging.
Package #1 resembles a cell phone and may be portable with rechargable batteries and clip for attachment to clothing of the driver of a mass transit vehicle such as a school bus. The style of siren is selected by memory to be that of the country of operation. When the siren is activated by an RF signal from an emergency vehicle, the volume will be sufficient to over ride the noise of passangers.
Package #2 is meant to be used at traffic intersection in the same fashion that ringing bells and flashing lights warn road traffic at railroad crossings. It will be a large, weatherproof device mounted at traffic signals in the same fashion police cameras are mounted and powered. The loudness will be the same 80-90 dBa as the emergency vehicle siren, thereby providing earlier warning and longer time for vehicles at the intersection to take evasive action.