Multiple Nuclei Model in Urban and Regional Planning

The multiple nuclei model is an economical model created by Harris and Edward Ullman in 1945
This model describes the layout of a city, it is based off of Chicago
Modern cities more complex than suggested by other theorists
Each nucleus acts as a growth point
Growth occurs outwards from each nucleus, until they all merge into one large urban area
It says even though a city may have begun with a CBD, it will have other smaller CBDs develop on the outskirts of the city
If other CBDs develop on the outskirts of a city they would be around valuable housing areas to allow shorter commutes to the outskirts of the city
Reason for the Model
Harris and Ullman argued that cities don't grow a single nucleus but several separate nuclei
Each nucleus acts like a growth point
The theory was formed based on the idea that people have greater movement due to increased car ownership
This increase of movement allows for the specialization of regional centers
The number of nuclei around which the city expands depends upon situational as well as historical factors Reasons for the Model Continued
Effects on Industry
As multiple nuclei develop, certain types of transportations like airports are created
Those allow industries to be established with a reduction in transportation cost
These transportation hubs have negative effects
Some effects are noise pollution and lower land values
Hotels are also built around airports because people who travel want to be near their source of transportation
Placement of Classes
Low Class: Low class residential area are closer to the manufacturing jobs which tend to be non-minimal skilled jobs. They also tend to have low wages which in turn lead to a low-class resident
Medium Class: Medium class residential area tends to be close to the CBD. It also has more space to spread out to support the population which are doing the skilled-labor jobs
High Class: High class residential areas tend to be on the outskirts of the medium class residential area. The area is also touching the outlying business district. The jobs that the people in this district do are usually skilled labor and have high incomes.
https://aboutcivil.org/multiple-nuclei-model

