I would kill the glass or make sure casts shadows, accepts shadows, self shadows are off for the panes. Turn refraction to 0. Remove the posters or whatever they are from glass. Make sure that glass touches nothing else. Copy the material from one of cars (windows) if cars didn't add appreciably to render time. Or Hide bus stop for all renders and after final is done plop render window around bus stop. Export image and edit main render in graphic editor, pasting the plop rendered area into main render. I would lose glass and then add glass in PhotoShop