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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.
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]
[link]
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What about drivers approaching from the side on
intersecting roads? Don't they need to hear the siren? |
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How about sirens that operate on car radio RDS TA (Traffic Announcement) signals, so that they can break through whatever drivers are listening to? |
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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. |
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If it was a rotating parabolic reflector, then it would only wake
you up once per revolution. Much better. |
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//How about sirens that operate on car radio RDS TA (Traffic Announcement) signals, so that they can break through whatever drivers are listening to?// |
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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. |
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//there are other things on the road (pedestrians, bikes, motorcycles, // Things of little or no consequence, in other words. |
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//Things of little or no consequence, in other words.// |
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Say that again the first time you end up with a flat because a rib goes through your tire. |
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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. |
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Perhaps one solution is to find a sound which is less
likely to wake people up, but capable of drawing
attention. |
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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. |
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// ...motorcycles, etc. // // things of little or no
consequence // |
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White noise is the letters to the editor column when
banks increase mortgage rates, isn't it? |
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