Taking Control of Traffic - Electronically

With the improved soundproofing of today's passenger vehicles, with audio systems capable of delivering deafening sound levels, and with windows closed and air conditioners humming away, you can't always take for granted that you've broken into the...


This column is a component of VFIS' "Operation Safe Arrival" initiative, aimed at heightening safety awareness and reducing the frequency and severity of accidents involving emergency vehicles.

Emergency vehicle operators take note: even with your sirens blaring away, civilian drivers can't always hear you coming.

With the improved soundproofing of today's passenger vehicles, with audio systems capable of delivering deafening sound levels, and with windows closed and air conditioners humming away, you can't always take for granted that you've broken into the motoring public's cocoon-like surroundings. Even if they can hear you, siren sounds can be reflected off buildings, altering their direction. This creates confusion and may cause other drivers to respond in a way that isn't expected. If that wasn't enough, it has become increasingly apparent that the public is more casual about yielding to emergency vehicles than in the past.

The good news is there are several solutions available to emergency service operations. One system involves the use of special "emitters" (strobe lights) on emergency vehicles that communicate with sensors mounted on traffic lights. As the emergency vehicle approaches, the sensor communicates with the traffic light's phase selector, changing it to green in the direction the vehicle is traveling and red in all other directions.

A similar but newer system is activated by the emergency vehicle's siren. In this case, a microphone on the traffic signal picks up the siren and transfers the information to the phase selector. The microphone can be adjusted to pick up signals from as much as a half mile away. This more sophisticated system requires the installation of white and blue lights next to current traffic signals. White signals the emergency vehicle that a green light is imminent, blue signals civilian drivers that an emergency vehicle is approaching, and they must stop.

Another concept now under development involves a transmitter mounted in the emergency vehicle and a receiver incorporated into passenger vehicle radios. The transmitter emits a coded signal -- much like a garage door opener -- that turns on the passenger vehicle's audio system, or switches the system from CD or cassette to radio. This is followed by a pre-recorded broadcast message such as "emergency vehicle approaching. Yield the right of way, move to the right and stop." After the system times out, the passenger automobile's audio is restored to its previous operational condition. While all of this is technically feasible, the major hurdle will be to get legislation passed that makes the special circuitry mandatory in all vehicles.

Remember, though, no matter what system is used, it can not replace proper emergency vehicle driving practices.

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