Ah, but they look like they have velcro closers. I used to wear a yellow fluro bib when I commuted, but I ended up buying one with a zip.
It's a bit distracting filtering at the ton on a motorway* with your bib flapping under your armpits and behind your back.
GC
* not on an XBR, I hasten to add, but on my big blue VX800.