On my commute I drive across a 60 mph bridge. The bridge is 3 lanes each way, lane A comes from traffic lights and leaves the bridge to a different exit, it is its own slip road so you would only want to be in lane A to come off in that place.
Lanes B and C both come onto the bridge from an expressway so traffic is moving at 60mph. Both lanes go to the same place and B has various slip roads.
So I come onto the bridge in lane A but need to leave from a slip road on lane B.
So often someone in front of me only builds up speed to 45mph, because lane B is moving at 60mph straight off the expressway it is very difficult to then swap lanes to B without matching their speed.
AiBU to think that actually it is very dangerous to drive at 45mph on a 60mph road and hold up those behind you? I am a fairly new driver so I don't know if I am missing something or being impatient.