I'm not here to describe the logic, just to warn you of it. Tonight and Saturday night, I-95 northbound will be closed at State Road 112 (Exit 4B) and southbound between Miami Gardens Drive and NW 135th Street. The closures will begin at 11 p.m. and finish at 10 the following morning. Workers are busy constructing express lanes.
I warn you because I got stuck in it last Saturday, and it ruined my night. I got on at the junction, and traffic was flowing fine until right after Exit 3B. It then took me about 40 minutes (maybe more; I lost track of time shortly before I lost track of my will to live) to get off Et exit 4B. A trip that usually takes 40 seconds.
You do not want to get stuck in this. The only reason to get on 95 this weekend from the junction is to head to downtown or South Beach via one of the various Exit 2s. All others, steer clear.