I really do not understand the point. If one can make a feedback system capable of effectively and intelligently guiding a blind person it wouldn't be necessary... Just make the car capable of driving itself. A sighted person has a hard enough time interpreting and reacting to evolving situations around them. Responding to vibrations and voice alerts is most certainly slower.
Exactly, last summer I had a kid run right out infront of my car, the only reason he isn't dead is because I saw him out of the corner of my eye and my brain knew without really thinking about it that at the speed he was moving he wasn't stopping at the curb. I was already putting on the breaks before he had placed one foot on the road. I'm sorry but this system no matter how good it is, will never be able to warn a blind driver in time for split second reactions.