In higher density environments, incorporating natural settings into the landscape design can have positive impacts, such as increased happiness, decreased stress, and a reduction in maintenance costs.
Transit-oriented development involves high-density residential and mixed-use buildings within walkable precincts around public transport nodes, often referred to as activity centres.
The third approach is to require that all new development on the urban fringe of existing metropolitan areas is at higher densities than the current average for those cities.
[3] Throughout the 20th century, implementation of urban consolidation policies appears to come in 'waves', separated by population surges stemming from major events like World War I and II.
As a city's infrastructure is used by an increasing number of people, the systems must be upgraded and retrofitted, a process which can cost hundreds of millions of dollars.