DOH!  i'll never trust spell checking again....  incidentally, i believe
they do use a similar sound here now, in any case it does usually vary
considerable and they actually have several sounds, switching to a more
obnoxious one when trying to get more attention like at an intersection
or when some idiot won't get out of the way.  seriously, i've actually
seen people run across a 4 lane street in front of an ambulance!  pretty
stupid, and they were my fellow college students, but i already new that
being in college didn't have much to do with intelligence or the ability
to survive.  there was no other traffic due to the lights changing for
the ambulance, but if one had tripped the ambulance probably would have
had to swerve to avoid their silly butts, fortunately (or unfortunately
from an evolutionary point of view) they all made it.  then again street
pizza probably would have made me late for class.

Howard Winter wrote:
>
> Philip,
>
> On Tue, 15 Jun 2004 21:30:59 -0600, Philip Stortz wrote:
>
> > in texas it's legal to buy a bear at 7-11
>
> Unless it's a Polar bear, of course, when it would be cruel to keep it in all that heat :-)
>
> > it could be argued that they should have coded rf transmitters in
> > emergency vehicles resounding to a call so that cars could have
> > receivers to alert drivers to the distance and direction of approach of
> > emergency vehicles (without depending on people hearing and usually much
> > later seeing them), i know it is sometimes hard to tell at first if they
> > are close and what direction they are coming from, and i don't play the
> > stereo loud, with some of today's idiots it's a wonder there aren't more
> > emergency vehicle collisions, and there are a lot.
>
> Actually they could do a lot to improve things without this - experiments on the sound that emergency vehicles
> make discovered that they normally produce a sine wave, albeit of a varying frequency, and the human ear is
> very bad at detecting direction in this case.  They (Manchester University, I think) developed a sound that
> was much more effective: it was a fast-warbling "yelp" note that lasted for about 1.25 sec, then two loud
> rasping white noise bursts (with emphasis on the lower frequencies, I think, so perhaps pink noise), then
> repeated.
>
> It sounded something like:  WeeWeeWeeWee  Pzzzzt  Pzzzzt,  taking about 2 sec to do each sequence.
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