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Topic 2 – Transportation Systems and Networks. Transportation and Commercial Geography Transport Costs Transportation Networks Transportation Supply and Demand. C – Transportation Networks. 1. Transport Networks 2. The Topology and Typology of Networks 3. Networks and Space .
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Topic 2 – Transportation Systems and Networks Transportation and Commercial Geography Transport Costs Transportation Networks 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 Centripetal Centrifugal
Network Structures Centralized Decentralized Distributed
Transport Hub Point-to-Point Hub-and-Spoke Hub
Cost, Revenue and Level of Network Coverage Cost: 10 Revenue: 15 Benefit: 5 4 5 A 10 3 7 Cost: 12 Revenue: 18 Benefit: 6 B Cost: 14 Revenue: 25 Benefit: 11 C Cost: 19 Revenue: 29 Benefit: 10 D
Impacts of Integration Processes on Networks and Flows After Integration Before Integration International border Network Flows
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 Unidirectional link Bi-directional link Entry and exit Exit Link Entry Node
Types of Network Topology Hub-and-Spoke Mesh Tree Linear
Network Strategies to Service a Set of Locations A B C E F D
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 Overlap Air corridor Rail “No service” Road Cellular coverage Maritime corridor Without definition Vaguely defined Clearly defined
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 30 minutes 10 km
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.
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)
Passenger-Miles Transported within the United States, 1975-2000 (millions)
Share of Total Domestic Freight Activity by Mode, G7 Countries, 1996
Growth Factors in Transport Demand Passengers Freight Passenger or ton-kms Growth in production and consumption Income growth Quantity of Passengers or Freight Industrial relocation Economic specialization Suburbanization KM Average Distance
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 • Tracks • Grade • Corridors • Canals • Locks Routes • Parking • Yards • Transshipment • Runways • Dockways • Docks • Transshipment Terminals • Speed • Passengers • Tonnage • Speed • Passengers • Tonnage • Speed • Passengers • Tonnage • Speed • Tonnage Vehicles Atmospheric Conditions
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 Cost Demand Supply D S1 S2 Equilibrium C1 C2 T2 T1 Traffic
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 100% Emergency Commuting Major Purchase Special Event Traffic Social Activities Recreation 0% Cost
Transport Supply, Demand and Travel Time Transport supply (A) Traffic Transport Demand (T) Morning peak Afternoon peak Travel time T>A T<A Time of the Day