Most horses, especially if they ride on pavement regularly, have steel "shoes", so a typical horse is anything but silent.
I was on London Heathrow airport recently and the "golfcart" style courtesy people movers (which bring phycically challenged passengers to/from their gate) have an interesting audible warning sound: It is a pulsing white noise signal, as if they have an air pump that is overfilling a brake reservoir and that is releasing a puff of air every second. Pfft....Pfft....Pfft. It is loud enough that you can hear it from quite a distance away when it is quiet, I am guessing about 500 ft away is already attracts attention, but when it is near it is not an unpleasant sound, certainly preferable over the idiotic backup beeper style warning devices. *if* silent vehicles need a warning signal then this would be a decent candidate for it. But nothing beats an attentive driver interacting with attentive fellow traffic participants. Note that I used the term "traffic" as defined by law - anybody moving about on the road, not the narrow definition that some people mistakenly use as in "other cars". Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: [email protected] Private: http://www.cvandewater.info Skype: cor_van_de_water Tel: +1 408 383 7626 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Lee Hart Sent: Thursday, July 04, 2013 11:16 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] silent EVs I can't help but contribute to this anti-sense. Sorry; I can't help myself! :-) If the point is that people should be able to detect the presence of cars by their sound, then they'd have to come up with an approximate "standard sound" that all cars must make. Otherwise, we'll have add-on car sounds that people have no trouble hearing, but that will *not* alert people to the fact that it's coming from a car. There is also the risk of starting a noise pollution war, just like the light pollution war that emergency vehicles have experienced. First, police cars started with one blinking light. Since no other car had blinking lights, people noticed it. But soon, lots of cars have blinking lights. So you add more, and brighter blinking lights. So now, emergency have more blinking lights than Christmas trees. If you allow any sort of add-on noise, it won't take long for Marketing to set in. Just as we have deliberate vehicle sounds like sirens and ice cream trucks, we'll have companies selling all sorts of novelty sound effects. The carmakers will realize that they can make their vehicles make marketable noises, that "advertises" their products. You know what I'd like to see? Robert Heinlein used a gadget in a science fiction story called a "Fenton Silencer". It picked up undesired ambient sound, inverted it, and re-broadcast it to cancel out the noise. It *reduced* the noise level, instead of adding more noise pollution. Today, we have the technology to actually do this. So let's put these in cars, to make our streets *quieter* instead of noisier. For the blind or handicapped, I would suggest that there may be other more appropriate technologies than mandating car noisemakers. Why not consider radar or sonar based devices, which are far more accurate at detecting and locating a potentially dangerous approaching vehicle? These can even detect a silent bicyclist, or man on a horse! -- The greatest pleasure in life is to create something that wasn't there before. -- Roy Spence -- Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
