I have a fairly long steel grate vertical lift bridge I need to cross every day. I use the walkway when it's wet or icy out. It's kind of nasty even when dry. With skinny tires the expansion joints are a real hazard.
This particular bridge has the equivalent of studs (little steel nubs sticking up). It would really suck to go down on those. My advice would be to walk it if you are slipping all over the place.