If someone is prepared to look, Hi Viz is much easier to see.
There maybe an argument that it would confuse the person as to what they are looking at, but to me I think ah, that must be a motorcyclist.
A while ago a got a bulk order of ex police jackets that were great, personally I've gone off wearing it now & just rely on a couple of straps on my rucksac.
I searched for where I got them from , think they don't have them now, but do you like this?
http://www.the-outdoor.co.uk/ishop/853/shopscr440.html