>And for those who are partially sighted or blind some sort of warning device + appropriate signal could no doubt have been engineered and legislated. What do

>And for those who are partially sighted or blind some sort of warning device + appropriate signal could no doubt have been engineered and legislated. What do you have in mind? I can’t think of anything as effective as sound—the blind person needs no special hardware to perceive it, and it can be easily spatially localized.