The main reason cities in Switzerland do not have new large suburbs is that since the last version of the federal spatial planning act has been accepted by the

The main reason cities in Switzerland do not have new large suburbs is that since the last version of the federal spatial planning act has been accepted by the voters in 2014 there is a strict restriction on the buildings that can be built outside designated urban areas (in canton Vaud where Lausanne is it is 1 % of additional population per year, details may vary by canton). The planned amount of buildings outside these areas is enforced via zoning rule (only some land can be built and ant a given density. The main idea of this law is to avoid destroying farm land (which is important for strategic and ecological reasons) and increasing density of cities (which reduces various infrastructure costs compared to urban sprawl).