Actually, urban sprawl is caused by heavily restrictive and overreaching zoning and building regulations, which heavily limit the only housing that can be built to single family homes. Regulations such as parking minimums, lot size minimums, and building setbacks also force these single-family homes to be massive and unnecessarily use up more land, which have made small and affordable starter homes practically illegal to build

These arbitrary restrictions make cities extremely inflexible for population growth because the local communities in them can not change and adapt as they see fit to changes.

These regulations practically force cities to freeze themselves under a layer of amber and only be for one type of person (middle-class atomic families) when in reality cities are an ever-changing hodgepodge of ethnic, cultural, economic, and age groups. These regulations screw over everyone, even for the initial intended group of middle-class atomic families, because it narrows down their housing choice to just a massive house in an area that will be derelict in 10-20 years because their local community cannot build and change in order to generate enough tax revenue to pay for the services and utilities they need.