A good friend of mine had an amazing experience showing what blind people are capable of. He overheard a middle aged man who had obviously been blind for a long time schooling a young girl who had recently gone blind on how to get around. They were standing on one side of the road in a quiet neighborhood, and the man was teaching the girl how to assess the distance across the road. The way he did this was absolutely incredible: tap the cane on the curb, and you can hear the echo from the curb and buildings across the road. With experience you can hear how far it is.