A certain number of people have to live their lives outdoors between 8 a.m. and 8 p.m., and a certain number of people can only leave their homes between 8 p.m. and 8 a.m. So basically, public life has to be lived in these shifts, in order for everyone to fit on the streets because there's just no more room for any more infrastructure, any more highways. So it polarizes the community into day people and night people, and it becomes sort of a metaphor for racism and classism.
