I haven't noticed an especially low speed limit along there but then we're normally tootling slowly along the bridge pavement looking at the views.You're kidding me! I was at UCNW from 1972 to 1975. I lived off Glanrafon Hill, and later in a village on Anglesey called Llanddaniel Fab. My only claim to any kind of fame is that I rode my motorbike at 5 times the speed limit past that very sign. (The Menai Bridge speed limit was 15 mph, but don't let that spoil anything.)
The traffic jams on the mainland end are EPIC. It's such fun to swoosh past them on the cyclepath.