The CBD or Central Business District is the commercial centre. It contains
the main shops, offices and financial institutions of the urban area.
It is usually the most accessible (easy to get to) part of the city.
This is because most of the main transport routes lead here. Due
to high land values, buildings tend to be tall and building density
values tend to be very high, this is the result of great competition
to locate here. It is cheaper to build up than out. Also, there is a
limited amount of open space available. New developments tend to focus
on redeveloping existing areas rather than using the limited open space