GEO 106 Lecture Notes - Lecture 5: Transportation Planning, Traffic Flow, Microwave Oven
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Lecture 5 (Part 1) - Spatial Interactions & Behaviours
- Spatial Interactions
- Spatial interaction is the flow of goods, people, services and information among
places in response to a supply and demand relationship, that is often expressed
over a geographical space (between a point of origin and a point of destination)
- Spatial interactions include a variety of movement, such as travel, migration,
transmission of information, journeys to work or shopping, or the movement of
- Physical flows…
- Involve the movement of goods, people, materials, and other tangible commodities,
between the different nodes of the city along
- transportation channels
- Commuters going to and from work using roads or subways
- Migration of people within or between cities, or suburbs to cities, or vice versa
- Non-physical flows…
- Refer to the transmission of more intangible commodities, such as information, between
nodes in the city along sometimes less visible
- transmission channels.
- Flow of electricity, telecommunications, and the internet along telephone wires
- Cell phone signals
- Flow of ideas that occurs within a classroom. As you interact with other people, this may
include the diffusion of ideas or new technologies.
Require some type of infrastructure
Occur at various scales, from the individual through the neighbourhood, to the city,
region, country and globe.
Occur in various ways, ranging from tangible things moving along tangible channels to
intangible things moving along intangible channels
Collectively, all of this is known as spatial interaction and should be viewed as an
integral part of both your everyday life and that of the city, essential to its growth and
functioning, and by analogy is like the vascular and nervous systems of the human body.
-The Roles of Spatial Interaction
-It permits integration of the various spatially separated parts of the city, such as work
It permits differentiation and specialisation
within the system.
It acts to organise the system, since the magnitude and nature of the flows create and
define the hierarchical levels that exist in the system.
It can act as an agent of change since it provides the means by which new commodities
(e.g. new fashions) and new ideas/opinions (e.g. "we need a new government") move
within the system.
-The Importance of Transportation
-Transportation infrastructure is an important part of life:
North American cities with more than 100,000 people use between 25% and 35% of
their land area for streets and highways. Smaller cities use more – about 35% to 50%.
Parking for cars and other vehicles
-Ullman’s Three Principles of Spatial Interaction
-Complementarity: a deficit of a good in one place and a surplus in another
Transferability: possibility of transport of goods or products at a cost that the market will
Intervening opportunities: where similar goods or products are not available at a closer
-Why Transportation Networks Happen
Transportation networks are a product of existing or potential demand for interaction
In Ullman’s terms, complementarity has to exist for transferability to be created
Put another way, transferability is relative to complementarity – that is…
-No matter how easy the terrain is, no route will develop unless demand for it exists.
No matter how difficult the terrain is, routes will develop if there is sufficient demand for
Bottom line is that building infrastructure without demand for it does not lead to economic
If you build it, they don’t necessarily come.
-Impediments to Spatial Interaction
-Transportation planning is important because connecting land uses and people is
essential for the connectivity that allows them to work
Barriers to movement reduce the ability of a system to adapt – topography, bridges,
tunnels, limited connectivity.
Volume of traffic slows the pace of interaction
Any flow system – roads, public transit, footpaths – fall victim to the “Field of Dreams”
-If you build it, they will most likely come:Latent Demand
-Latent demand is basically the desire for a product or service that a consumer is unable
to satisfy because the consumer is unable to point it out or doesn’t realise what is
missing until it is pointed out
This need cannot be satisfied by a current product or service and the consumer
herself/himself cannot articulate the type of product which will help her/him
For example, the microwave oven tapped latent demand for faster preparation of food. It
is a product that saves customers time or labor.
For example, Highway 407
-The Field of Dreams Effect
-The problem is that when demand does exist, if you build it they most certainly do
This is the Field of Dreams Effect:
No matter how many roads you build, volume will come to fill them.
Research shows that a 1% decrease in traffic volume (number of vehicles) results in an
18% increase in traffic flow (movement of vehicles).
-Toronto Tom-Tom Congestion Data 2015
World rank compared to other
Highways (extra travel time)
Non-highways (extra travel time)
Extra travel time per day