GEOG 80 – Transport GeographyProfessor: Dr. Jean-Paul Rodrigue

Topic 2 – Transportation Systems and Networks

A. Transportation and Commercial GeographyB. Transport CostsC. Transportation NetworksD. Transportation Supply and Demand

C – Transportation Networks

■ 1. Transport Networks■ 2. The Topology and Typology of Networks■ 3. Networks and Space

1. Transport Networks

■ Transport network• Framework of routes between locations:

• A permanent track (e.g. roads, rail and canals).• A scheduled service (e.g. airline, transit, train).

• Various types of links between points along which movement can take place.

• Creates accessibility.■ Network structure• Ranges from centripetal to centrifugal.• Express inequalities between places.• Express transport rates.• Integration processes impacted on the structure and flows of

transportation networks.

Centrifugal and Centripetal Networks

Centrifugal Centripetal

Network Structures

Centralized Decentralized Distributed

Transport Hub

Point-to-Point Hub-and-Spoke

Hub

Cost, Revenue and Level of Network Coverage

5

37

410

Cost: 10Revenue: 15Benefit: 5

A

Cost: 12Revenue: 18Benefit: 6

B

Cost: 14Revenue: 25Benefit: 11

C

Cost: 19Revenue: 29Benefit: 10

D

Impacts of Integration Processes on Networks and FlowsN

etw

ork

Flo

ws

Before Integration After IntegrationInternational border

2. The Topology and Typology of Networks

■ Topology• The arrangement and connectivity of a network.• Each network has a specific topology.

Topology of a Network

Node

Link

Unidirectional link

Bi-directional link

Entry and exit

ExitEntry

Types of Network Topology

Mesh Hub-and-Spoke

Linear Tree

Network Strategies to Service a Set of Locations

A B C

D E F

2. The Topology and Typology of Networks

■ Mode of territorial occupation• Clearly defined and delimited:

• Strictly reserved space for transport infrastructure.• Ownership can also be clearly established.• Major examples include road, canal and railway networks.

• Vaguely defined and delimited:• Space may be shared with other modes.• Not the object of any particular ownership, only rights of passage.• Examples include air and maritime transportation networks.

• Without definition:• Space has no tangible meaning, except for the distance it imposes.• Little control and ownership are possible.• Agreements must be reached for common usage.• Examples are radio, television and cellular networks.

Mode of Territorial Occupation by Transport Networks

Clearly defined Vaguely defined Without definition

Road

Rail Air corridor

Maritime corridor Cellular coverage

Overlap

“No service”

3. Networks and Space

■ Transportation networks and space• Territorial organization of economic activities.• Efforts incurred to overcome distance.• Measured in absolute or relative terms• Related to continuity, topographic space and spatial control.• The territory is a topological space having two or three

dimensions, depending on the transport mode considered.• Flows and infrastructures are linear; having one dimension.

Transport Networks and Space

Transport Network

Space

Accessibility

Absolute and Relative Distance in a Network

10 km 30 minutes

3. Networks and Space

■ Spatial continuity• Ubiquity:

• The possibility to reach any location from any other location. • Fractionalization:

• The possibility for a traveler or an unit of freight to be transported without depending on a group.

• Instantaneous:• The possibility to undertake transportation at the desired moment.

■ Topographic space• Not a continuous space.• Variety of physical features.• Level of influence on the structure of transport networks:

• Depends on the mode.

Networks and Spatial Continuity

A B

C

3. Networks and Space

■ Tool for spatial control• Roman and Chinese empires relied on transportation networks to

control their respective territories.• During the colonial era, maritime networks became a significant

tool of trade, exploitation and political control.• In the 19th century, transportation networks also became a tool

of nation building and political control.• In the 20th century, road and highways systems were built to

reinforce this purpose.• For the early 21st century, telecommunication networks have

become means of spatial cohesion and interactions.

D – Transportation Supply and Demand

■ 1. Context■ 2. Supply and Demand Functions■ 3. Supply / Demand Relationships

1. Context

■ Transport supply• The capacity of infrastructures and transport modes.• Over a geographically defined transport system and for a specific

period of time.• Expressed in terms of infrastructures, services and networks.• Quantification:

• Per unit of time and space.• Number of passengers.• Volume (for liquids or containerized traffic).• Mass (for freight).

1. Context

■ Transport demand• Expression of the transport needs of a territory:

• Generated by the economy.• Composed persons, institutions and industries.• Generates movements of people and freight

• Those needs can be satisfied, fully, partially or not at all.• Quantification:

• Number of people, volume, or tons per unit of time and space. ■ Ton-km and Passenger-km• Measures expressing the realized transport demand.• Compares a transported quantity with a distance.

Ton-Miles of Freight Transported within the United States, 1975-2000 (millions)

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

4,000,000

1975 1980 1985 1990 1995 2000

Air

Water

Pilelines

Truck

Rail

Passenger-Miles Transported within the United States, 1975-2000 (millions)

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

1975 1980 1985 1990 1995 2000

Rail

Urban Transit

Bus

Car

Air

Share of Total Domestic Freight Activity by Mode, G7 Countries, 1996

0

10

20

30

40

50

60

70

80

90

100

Canada France Germany Italy Japan UnitedKingdom

UnitedStates

% o

f tot

al d

omes

tic m

etri

c to

n-km

RoadRailOil PipelineWaterAir

Growth Factors in Transport Demand

Qua

ntity

of P

asse

nger

s or

Fre

ight

Average Distance

Growth in production and consumption

Income growth

Industrial relocationEconomic specialization

Suburbanization

Passenger or to

n-kms

KM

PassengersFreight

2. Supply and Demand Functions

■ Transport supply• Functions representing what are the main variables influencing

the capacity of transport systems.• Variables are different for each mode.• Road, rail and telecommunications:

• Dependent on the capacity of the routes and the vehicles.• Air and maritime transportation:

• Influenced by the capacity of the terminals.• Transport of people and freight:

• Expressed in number of vehicles, people or tons over a time period.• The supply of one mode influences the supply of others.• Dependent of the capacity of intermodal infrastructures.

Major Supply Variables for Transportation Modes

Road Rail Air Maritime•Lanes•Width•Speed limit

•Parking

•Speed•Passengers•Tonnage

Atmospheric Conditions

•Tracks•Grade

•Yards•Transshipment

•Speed•Passengers•Tonnage

•Corridors

•Speed•Passengers•Tonnage

•Runways•Dockways

•Canals•Locks

•Docks•Transshipment

•Speed•Tonnage

Rou

tes

Term

inals

Veh

icle

s

2. Supply and Demand Functions

■ Transport demand• Related to economic and social activity patterns.• Stable and recurrent; allows the planning of services.• Unstable and uncertain; difficult to offer an adequate level of

service. • Passengers:

• Function of demographic attributes of the population such as income, age, standard of living, race and sex, as well as modal preferences.

• Freight:• Function of economic activities (GDP, commercial surface, number of

tons of ore extracted, etc.) and of modal preferences. • Information:

• Population (telephone calls) and the volume of financial activities (stock exchange).

• Standard of living and education levels.

3. Supply / Demand Relationships

■ Transport supply and demand interactions• Supply curve:

• Quantity of transport services offered according to price.• The higher the price, the more suppliers are willing to offer a transport

service.• Demand curve:

• Quantity of transport services consumed according to price.• The higher the price, the less users are willing to consume that service.

• Equilibrium price:• Supply and demand interact until an equilibrium is reached.• Quantity of transportation the market is willing to use at a given price.• Quantity being supplied.

Classic Transport Demand / Supply Function

Traffic

CostDemand Supply

T1

C1

D

S1S2

C2

T2

12

12

CC

TTElasticity

Equilibrium

2. Supply and Demand Functions

■ Considerations• Entry costs:

• High in some sectors (maritime, rail and air). Oligopolisitc.• Low in other (trucking).

• Public sector:• High level of public involvement. • Provision of transport infrastructures.• Transport costs are partially subsidized.• Government control (and direct ownership).

• Elasticity.• Variation of demand in response to a variation of cost.• Transport demand has a tendency to be inelastic.• Commuting: inelastic in terms of costs but elastic in terms of time.• Freight: inelastic.• Air transportation: elastic (tourism).

Transport Elasticity by Activity

Traffic

Cost

100%

0%

Emergency

Commuting

Major Purchase

Special Event

Social Activities

Recreation

T>A

T<A

Transport Supply, Demand and Travel Time

Transport supply (A)

Transport Demand (T)

Time of the Day

Trav

el ti

me

Morningpeak

Afternoonpeak

Traf

fic