re: Why don't they build a foot bridge from campus to Northgate?

Speed bumps on a six lane road would be a nightmare and people wouldn't use the pedestrian ramps.

The only thing I can think of that might work to everyone's benefit is closing the street down between Wellborn and College Main on gameday. The traffic issue though, ooof. The traffic through the backstreets would get pretty bad.

At least you would get some outdoor activity on the closed street between the bars and campus as a side benefit but there is no easy answer with this one.