Perhaps this is one of those cases where we're not approaching the problem in a logical manner, noting the following reasons (among others):
(1) Stopping someone from stepping out in front of a moving vehicle is a much more straightforward proposition than stopping the vehicle after someone has stepped out in front it.
(2) Providing technology to mobile blind people would be less expensive (at least in a global sense) than putting it on cars.
(3) The key areas of interest are parking lots and other low-speed areas because hybrids use their gas engines on city streets and therefore sound pretty much like any other small-engine car (which are also very quiet, if you discount those goofy-sounding modified civics).
(4) As has already been pointed out, anything we put on cars will also have to be put on bicycles and other quiet, fast-moving objects.
(5) If you truly think about it objectively, wouldn't it be silly to outlaw quiet vehicles?
I don't know the solution, but with the wide array of available sensor technologies it certainly falls far below the level of rocket science ... this would be a great place for one of you entrepreneurs to step in and save the day ...
Regards,
Greg
