Transportation costs for everything go down, including food, water, electricity, etc. Public transit becomes viable and, if well managed, superior to driving a

Transportation costs for everything go down, including food, water, electricity, etc. Public transit becomes viable and, if well managed, superior to driving a car. People tend to walk more instead of relying on vehicles for everything. Buildings and roads can serve more people per material used. I could go on, but having things close to each other makes using and bringing those things together cheaper.