People who dislike sirens do not go into the ambulance driving business. No, running those sirens is part of the package. But those sirens - many people hear them who are not in a position to block the road in front of the ambulance. Examples include people in their beds at 2 AM.

I propose that siren bearing vehicles in densely populated areas could use parabolic dishes behind the sirens. This would focus the siren noise forwards along the path of the vehicle. People to the side at some distance would hear the siren much less loudly.
-- bungston, May 01 2012

Directional smart siren Directional_20Smart_20Sirens
Besides waking people up, nondirectional sirens are less useful because at a distance, drivers cannot tell if they are in the path or not. [bungston, May 01 2012]

What about drivers approaching from the side on intersecting roads? Don't they need to hear the siren?
-- Alterother, May 01 2012


Apparently not.
-- UnaBubba, May 02 2012


How about sirens that operate on car radio RDS TA (Traffic Announcement) signals, so that they can break through whatever drivers are listening to?
-- AbsintheWithoutLeave, May 02 2012


Only works if the radio is turned on. Without extensive (and mandatory) modification, car radio receivers could not be externally activated, or even switched from CD to radio band. It would work with OnStar, but only GM vehicles have that.
-- Alterother, May 02 2012


If it was a rotating parabolic reflector, then it would only wake you up once per revolution. Much better.
-- Ling, May 02 2012


//How about sirens that operate on car radio RDS TA (Traffic Announcement) signals, so that they can break through whatever drivers are listening to?//

Only if its in conjunction with a regular siren, since there are other things on the road (pedestrians, bikes, motorcycles, etc) that don't have a radio.
-- MechE, May 02 2012


//there are other things on the road (pedestrians, bikes, motorcycles, //
Things of little or no consequence, in other words.
-- TolpuddleSartre, May 02 2012


//Things of little or no consequence, in other words.//

Say that again the first time you end up with a flat because a rib goes through your tire.
-- MechE, May 02 2012


A planar siren could be useful it the area isn't too hilly. A flickable switch on the radio re: [MechE]'s anno more so, though you'd still need a real siren since a properly operating radio isn't mandatory equipment.
-- FlyingToaster, May 02 2012


Perhaps one solution is to find a sound which is less likely to wake people up, but capable of drawing attention.

Sirens which produce bursts of white noise have been tested (and may be in use), mainly because white noise is much easier to locate than a simple siren. My guess is that white noise is also less likely than a siren to wake up sleepers.
-- MaxwellBuchanan, May 02 2012


That's racist!
-- 2 fries shy of a happy meal, May 02 2012


// ...motorcycles, etc. // // things of little or no consequence //

<cough> ahem...
-- Alterother, May 02 2012


White noise is the letters to the editor column when banks increase mortgage rates, isn't it?
-- UnaBubba, May 03 2012



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