Study - Urban Bus (somewhere on Brazil)

Hey guys, this is an exercise that I made to challenge myself.
The idea here is draw something unusual and that I not used to draw.
So, I chose a scene that almost every citizen on Brazil knows well: normal people inside a urban bus (going on or back from work, or from school, whatever).
The objetive here is training proprotions and perspective, and background as well.
I expect you all like, guys! Thanks for watching.