Why wear bib shorts?

[Grog]

I feel that most shorts, at least the ones I have tend to ride up and rub around the 30 mile mark. I tend to start welcoming red lights so I can adjust it.
The bibs tend to keep everything in one place, they keep the shorts from twisting and moving.

I would perhaps volunteer that your previous shorts might have been a little bit too big. Bike shorts should be as small as you can fit into, which is often one size under what you'd normally feel comfortable buying. Then they won't be moving at all. And you should be able to find a pair that's comfy at the same time.

Hope that helps!