Promote high-density urban growth

Achieve the correct urban density to support sustainable and pleasant living is one of the trickiest problems cities are facing in address the future of their communities. In the United States, the typically low densities of suburban sprawl built in the last half of the 20th century have been revealed to produce unsustainable rates of driving, carbon emissions, pollution and adverse health impacts.
Many modern urban planners advocate higher densities because of the widely held theory that cities operate more efficiently when residents live in denser urban surroundings. When cities have high densities, they tend to be more walkable and have greater transportation options. When cities rely on automobiles as their primary means of transit, they lack sustainability and quality of life choices that can only come about when urban fabrics are built for their human users rather than their cars.