You should be able to tell that Peoria Street had auto traffic across the entire bridge over the Eisenhower (I-290), but then the University of Illinois at Chicago (UIC) took over this area in the 1960s (shortly after the sunken Blue Line was built). An expanded station house was built with a large waiting area which includes interior bike parking within the paid fare zone.
UIC has classrooms immediately north and south of the expressway and Blue Line so it’s in their students’ best interest to have good access to the train station.
How could the former road space be changed now to make this a better public space or plaza?
I think the first thing I would do is remove the curbs – if you’re riding a bike these get in the way.