I just drive alot and I go through tunnels all the time.
The bridges are narrow and because they offer a view people are slow and distracted on them. Also it takes forever to build a bridge.
Tunnels honestly can be dug very quickly and if they get rid of the rotary's the traffic nightmare could be averted in a year or two and for far less cost. Tunnels are easy to make wide and they generally don't slow traffic much.