Single-detached houses in the 416 are getting hard to come by - equally in terms of affordability and supply. This new reality has given rise to different forms of high-density housing, which the Canadian Home Builders' Association refers to as "missing middle" housing.

High density neighbourhoods solve many problems when designed to be self-sustained. The idea is that residents barely need to use their cars when going to work or shopping. However, if the high density community contains only residential development where residents need to exit that community to get to work or to shop that is when high density may cause more congestion than it solves. That's why Mississauga needs more downtown office buildings while the getting's good.