TG Chapter 1

The Geography of Transport Systems

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Chapter 1 – Transportation and GeographyMovements of people, freight and information have persistantly been fundamentalcomponents of human societies. Contemporary economic processes have been accompaniedby a significant growth in mobility and higher levels of accessibility. Although this trend canbe traced back to the industrial revolution, it significantly accelerated in the second half ofthe 20th century as trade was liberalized, economic blocs emerged and the comparativeadvantages of global labor and resources were used more efficiently. However, theseconditions are interdependent with the capacity to manage, support and expand movementsof passengers and freight as well as their underlying information flows. Societies have beenincreasingly dependent on their transport systems to support a wide variety of activitiesranging, among others, from commuting, supplying energy needs, to distributing partsbetween factories. Developing transport systems has been a continuous challenge to satisfymobility needs, to support economic development and to participate in the global economy.The goal of this introductory chapter is to provide a definition of the nature, role and functionof transport geography and where the discipline stands in regard to other disciplines. It alsounderlines the importance of specific dimensions such as nodes, locations, networks andinteractions. An historical perspective on the evolution of transport systems underlines theconsequences of technical innovations and how improvements in transportation wereinterdependent with contemporary economic and social changes.

Concept 1 – What is Transport Geography?

1. The Purpose of Transportation

"The ideal transport mode would instantaneous, free, have an unlimited capacityand always be available. It would render space obsolete. This is obviously notthe case. Space is a constraint for the construction of transport networks.Transportation appears to be an economic activity different from the others. Ittrades space with time and thus money" (translated from [Merlin, 1992]).

As the above quotation underlines, the purpose of transportation is to overcome space,which is shaped by a variety of human and physical constraints such as distance, time,administrative divisions and topography. Jointly, they confer a friction to anymovement, commonly known as the friction of space. However, these constraints andthe friction they create can only be partially circumscribed. The extent to which this isdone has a cost that varies greatly according to factors such as the distance involvedand the nature of what is being transported. The goal of transportation is thus totransform the geographical attributes of freight, people or information, from an originto a destination, conferring them an added value in the process. The convenience atwhich this can be done varies considerably.

Transportability is the convenience at which passengers, freight or informationcan be moved. It refers to transport costs, but also to the attributes of what is beingtransported (fragility, perishable, price). Some institutional factors can alsoinfluence transportability such as laws, borders and tariffs. If transportability wasoptimal, the spatial division of labor and production would be absolute at the


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global scale. Some goods, such as semiconductors, are almost reaching thiscondition since they have a high value to weight ratio.

What is also specific to the purpose of transportation is the fulfillment of a demand formobility, that is transportation can only exists if it moves people, freight andinformation around. Otherwise it simply loses its purpose as transportation is theoutcome of a derived demand. Consequently, any movement must consider thegeography it is taking place over which in turn is linked to spatial flows and theirpatterns. Urbanization, multinational corporations, the globalization of trade and theinternational division of labor are all forces shaping and taking advantage oftransportation at different, but often embedded, scales.

Working

Activity

Vacationing

Derived Demand

Manufacturing

CommutingTaxi

Air travelTouring bus

TrucksContainership

Direct

EnergyIndirect Warehousing

Transportation as a Derived Demand

What is occurring in one sector has impacts on another; demand for a good or service in onesector is derived from another. Transportation cannot exist alone and a movement cannot bestored. An unsold product can remain on the shelf of a store until a customer buys it (oftenwith discount incentives), but an unsold seat on a flight remains unsold and cannot bebrought back as additional capacity later. Many activities involve a derived transportationdemand, which comes in two categories:

• Direct derived demand. Considers that transportation activities (movements)directly the consequences of economic activities are a direct derived demand,without which they would not take place. For instance, work-related activitiescommonly involve commuting between the place of residence and the workplace.There is a supply of work in one location (residence) and a demand of labor inanother (workplace). For freight transportation, all the components of a supplychain require movements of raw materials, parts and finished products on modessuch as trucks, rail or containerships.

• Indirect derived demand. Considers movements created by the requirements ofother movements. The most obvious example is energy where fuel consumptionfrom transportation activities must be supplied by an energy production systemrequiring movements from zones of extraction to places of consumption.Warehousing can also be labeled as an indirect derived demand since it is a “nonmovement” of a freight element. Warehousing exists because it is virtually


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impossible to move commodities instantly from where they are produced to wherethey are consumed.

The fundamental purpose of transport is consequently geographic in nature, meaningthat it facilitates movement between different locations. Transport thus plays a role inthe structure and organization of space and territories. In the 19th century, the objectiveof transport planners was to cover the surface of the earth with circulation pathways. Inthe 20th century, this objective shifted to selecting itineraries, choosing transportmodes, augmenting the capacity of existing networks and to respond to the mobilityneeds of goods, people and services.

2. The Importance of Transportation

Transport represents one of the most important human activities worldwide. It is anindispensable component of the economy and plays a major role in spatial relationsbetween locations. Transport creates valuable links between regions and economicactivities, between population and the rest of the world. Transport is amultidimensional service, which affects several aspects of the economy. Its importanceis manifested through several points of view:

♦ Historical. Transport modes have played several different historical roles. Inthe rise of civilizations (Egypt, Rome and China), in the development ofpolitical and cultural societies (creation of social structures) and also in nationaldefense (Roman Empire, American road network).

♦ Social. Transport modes facilitate access to healthcare, welfare, and cultural orartistic events, thus performing a social service. They shape social interactionsby favoring the mobility of people. Transport has an impact on the whole ofsociety (users, suppliers, entrepreneurs, governments).

♦ Political. Governments play a critical role in transport as investors, decisionsmakers and actors are constrained by rules and regulations. The political role oftransportation is undeniable as governments often subsidize the mobility oftheir populations (highways, public transit, etc.). While most transport demandrelates to economic imperatives, many communication corridors have beenconstructed for political reasons. Transport thus has an impact on nationbuilding and national unity.

♦ Environmental. Despite the countless advantages of transport, itsenvironmental consequences are also significant. They include air and waterquality, noise level and public health. All decisions relating to transport shouldthus be evaluated on account of the corresponding environmental costs.

♦ Economic. The evolution of transport has always been linked to economicdevelopment. The construction of transport infrastructures also permitted thedevelopment of a corresponding transport industry (car manufacturing, airtransport companies, etc.). The transport sector is also an economic factor in theproduction of goods and services. It contributes to the value-added of economicactivities, facilitates economies of scale, influences land (real estate) value and


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the geographic specialization of regions. Transport is both a factor shaping anda consequence of economic activities.

Substantial empirical evidence indicates that the importance of transportation isgrowing. The following contemporary trends can be identified regarding this issue:

♦ Growth of the demand. The twentieth century, more than any other, has seen aconsiderable growth of the transport demand related to individual (passengers)as well as freight mobility. This growth is jointly the result of larger quantitiesof passengers and freight being moved, but also the longer distances over whichthey are carried. Recent trends still underline an ongoing process of growth,which has led to the multiplication of the number of journeys and a widevariety of modes servicing transport demands.

♦ Reduction of costs. Even though several transportation modes are veryexpensive to own and operate (ships and planes for instance), costs per unittransported have dropped significantly over the last decades. This implies thepossibility to overcome larger distances and further exploit the comparativeadvantages of space. However, this process is far from undermining the role oftransportation as lower costs were linked with longer distances. As a result, theshare of transport activities in the economy has remained relatively constant intime.

♦ Expansion of infrastructures. The above two trends have obviously extendedthe requirements for transport infrastructures both quantitatively andqualitatively. Roads, harbors, airports, telecommunication facilities andpipelines have expanded considerably to service new areas and adding capacityto existing networks. Transportation infrastructures are thus a major componentof the land use, notably in developed countries.

Facing these contemporary trends, an important part of the spatial differentiation of theeconomy is related to where resources (raw materials, capital, people, information etc.)are located and how well they can be distributed. Transport routes are established todistribute resources between places where they are abundant and places where they arescarce, but only if the constraints involved can be afforded.

Consequently, transportation has an important role to play in the new conditions thataffect global, national and regional economic entities. It is a strategic infrastructure thatis so embedded in the socio-economic life of individuals, institutions and corporationsthat it is often invisible to the consumer, but always part of all economic and socialfunctions. This is paradoxical as the perceived invisibility of transportation is derivedfrom its efficiency. If transport is disrupted or cease to operate, the consequences canbe dramatic. Many transport systems have become strategically invisible as no specificuser can have a competitive advantage over others. Numerous fallacies in the analysisof contemporary geographical processes have resulted from this misrepresentation andunderstanding the true role of transportation requires a grasp of its underlying conceptsand dimensions.


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3. Concepts and Dimensions of Transport Geography

Transportation interests geographers for two main reasons. First industries,infrastructures, equipment and networks occupy an important place in space andconstitute the basis of a complex spatial system. Second, since geography seeks toexplain the spatial relationships, networks are of specific interest to geographersbecause they are the main support of these interactions.

Transport geography is a sub-discipline of geography concerned aboutmovements of freight, people and information along with their physical andtransactional context. It tries to link spatial constraints and attributes with theorigin, the destination, the extent, the nature and the purpose of movements.

Transport geography, as a discipline, emerged from economic geography in the secondhalf of the twentieth century. Traditionally, transportation has been an important factorover the economic representations of the geographic space, namely in terms of thelocation of economic activities and the monetary costs of distance. The growingmobility of passengers and freight justified the emergence of transport geography as aspecialized field of investigation. In the 1960s, transport costs were recognized as keyfactors in location theories. However, from the 1970s globalization challenged thecentrality of transportation in many geographical and regional developmentinvestigations. As a result, transportation was under represented in the 1970s and1980s, even if mobility of people and freight and low transport costs were consideredas important factors behind the globalization of trade and production.

Transportnetworks

Transportdemand

Transportnodes

Informationsystems

Fieldmethods

Populationgeography

PoliticalGeography

Regionalplanning

Economicgeography

Historicalgeography

Regionalgeography

Regionaleconomics

Locationtheory

Naturalresources

Resourceplanning

Environmentalstudies

Spatialoptimization

Urbangeography

Landuse

Spatialstatistics,modeling

Cartography

Operationsresearch

Worldgeography

ECONOMICS

POLITICALSCIENCE

ECONOMICS

HISTORY

MATHEMATICS,COMPUTER SCIENCE

PLANNINGNATURAL SCIENCES

ECONOMICS,SOCIOLOGY

Fields at the core oftransport geography

Fields related totransport geography

Transport geography

Fields of Transport GeographySource: Adapted from P. Haggett (2001) Geography: A Modern Synthesis, 4th Edition, New York: Prentice Hall.

There are basically twelve key concepts related to transport geography, among whichtransportation networks, transportation nodes and transportation demand are at its core.They are closely linked to economic, political, regional, historical and populationgeography, among others. Several other concepts, such as regional planning, informationsystems, operations research and location theory are commonly used in transport geography,notably as tools and methods for the spatial analysis of transportation. At a wider level,reference to several major fields of science including natural sciences, mathematics andeconomics can also be made. Indeed, like geography, transport geography is at the


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intersection of several concepts and methods initially developed outside the discipline butadapted to its particular problems.

Since the 1990s, transport geography has received renewed attention, especiallybecause the issues of mobility, production and distribution are interrelated in a complexgeographical setting. It became recognized that transportation is a system that considersthe complex relationships between its core elements, which are networks, the demandand nodes. Transport geography must be systematic as one element of the transportsystem is linked with numerous others. An approach to transportation thus involvesseveral fields that can be at the core of transport geography or somewhat peripheraldepending on the concepts investigated. However, three central concepts to transportsystems can be identified:

♦ Transportation nodes. Transportation primarily links locations, oftencharacterized as nodes. They serve as access points to a distribution system oras transshipment / intermediary locations within a transport network. Thisfunction is mainly serviced by transport terminals. Transport geography mustconsider its places of convergence and transshipment.

♦ Transportation networks. Considers the spatial structure and organization oftransport infrastructures and terminals. Transport geography must include in itsinvestigation the infrastructures supporting and shaping movements.

♦ Transportation demand. Considers the demand for transport services as wellas the modes used to support movements. Once this demand is realized, itbecomes an interaction which flows through a transport network. Transportgeography must evaluate the factors affecting its derived demand function.

Nodes

Networks Demand

LocationsTerminals

Flows

Friction

PeopleFreight

Information

OriginsDestinationsIntermediacy

Linkages

The Transport System

The transport system can be conceptualized as the set of relationships between nodes,networks and demand. Demand for the movement of people, freight and information is aderived function of a variety of socioeconomic activities. Nodes are the locations wheremovements are originating, ending and being transferred. The concept of nodes variesaccording to the geographical scale being considered ranging from local to global (poles ofthe global economy). Networks are composed of a set of linkages derived from transportinfrastructures. The three core relationships and the impedance (friction) they are subject toare:


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• Locations. The level of spatial accumulation of socioeconomic activities jointlydefines demand and where this demand is taking place. Impedance is mostly afunction of the accessibility of nodes to the demand they service.

• Flows. The amount of traffic over the network, which is jointly a function of thedemand and the capacity of the linkages to support them. Flows are mainly subjectto the friction of space with distance being the most significant impedance factor.

• Terminals. The facilities enabling access to the network as terminals are jointlycharacterized by their nodality and the linkages that are radiated from them. Thecapacity of transport terminals to handle flows is the main impedance factor..

The analysis of these concepts relies on methodologies often developed by otherdisciplines such as economics, mathematics, planning and demography. Each providesa different dimension to transport geography. For instance, the spatial structure oftransportation networks can be analyzed with graph theory, which was initiallydeveloped for mathematics and computer science to deal with other problems. Further,many models developed for the analysis of movements, such as the gravity model,were inferred from physical sciences. Multidisciplinarity is consequently an importantattribute of transport geography, like geography in general.Given these varied dimensions what is the role of transport geography and of thetransport geographer? Basically, the transport geographer tries to draw linkagesbetween several or all of these dimensions in a systematic field of investigation whenthey involve spatial relations. The most relevant of these geographical considerationsto transport geography are:

♦ Location. As all activities are located somewhere, each location has its owncharacteristics conferring a potential supply and/or a demand for resources,products, services or labor. A location will determine the nature, the origin, thedestination, the distance and even the possibility of a movement to be realized.For instance, a city provides employment in various sectors of activity inaddition of being a consumer of resources.

♦ Complementarity. Locations must require exchanging goods, people orinformation. This implies that some locations have a surplus while others havea deficit. The only way an equilibrium can reached is by movements betweenlocations having surpluses and locations having demands. For instance, acomplementarity is created between a store (surplus of goods) and its customers(demand of goods).

♦ Scale. Movements generated by complementarity are occurring at differentscales, pending the nature of the activity. Scale illustrates how transportationsystems are established over local, regional and global geographies. Forinstance, home-to-work journeys generally have a local or regional scale, whilethe distribution network of a multinational corporation is most likely to coverseveral regions of the world.

Consequently, the transport systems, by their nature, have a strong spatial imprint.


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Concept 2 – Transportation and Space

1. Physical Constraints

Transport geography is concerned with movements, which are occurring over space.The features of this space impose major physical constraints on transportation systemsin terms of what mode can be used, the extent of the service, its costs and its capacity.A basic geographical feature of the terrestrial surface is its sphericity, which imposes aspecific geometry for movements, notably at the international level. Three basic spatialconstraints of the terrestrial space can be identified:

♦ Topography: Through relief’s altitude and landforms, topography affectstransport development. Features such as mountains and valleys have stronglyinfluenced the structure of networks, the cost and feasibility of transportationprojects. Main land transport infrastructures are built over plains, followvalleys, use mountain passes. Water transport is function of compulsorypassages imposed by water depth and the location of reefs. Coastlines exert aninfluence on the location of port infrastructure. Aircrafts require airfields ofconsiderable size in their taking off and landing operations. Topography canimpose a natural convergence of routes that will create a certain degree ofcentrality and will assist in becoming a centre of exchange both as a collectorand distributor of goods and produces that in many instances have led to theemergence of manufacturing, commercial and urban centers. Topography cancomplicate, postpone or prevent the activities of the transport industry.Transport activities are partly determined by particular landforms and theircapacity to sustain the periodic superimposition of transport infrastructure.Physical constraints fundamentally act as absolute and relative barriers tomovements. Land transportation networks are notably influenced by thetopography, as highways do not support a grade higher than 3% and railwaysup to 1%. Under such circumstances, land transportation tends to be of higherdensity in topographical flat areas.

♦ Hydrography: Features such as rivers, lakes and oceans influence navigation.Continental masses impose a maritime space that it is possible to simplify withobligatory passage points, which must be respected or circumscribed whenpossible (Panama and Suez canals are such achievements). It also imposesconstraints on land transportation necessitating the construction of bridges,tunnels and detours. It can also be a transport infrastructure on its own. Severalrivers such as the Mississippi, the St. Lawrence, the Rhine, the Mekong or theYangtse have seen the accumulation of human activities taking advantage of thetransport opportunities. Port sites are also highly influenced by the physicalattributes of the site where several natural features (bays, sand dunes, andfjords) are protecting port installations. Since it is at these installations thattraffic is transshipped, the location of ports is a dominant element in thestructure of maritime networks.

♦ Climate: The climate affecting a region includes temperature, wind andprecipitation. They impact on transportation modes and infrastructure in varied


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ways, ranging from negligible to severe, including hazardous operatingconditions. Freight and passenger movement can seriously be curtailed bysnow, heavy rainfall, ice or fog. Jet streams are also a major physicalcomponent that international air carriers must take into consideration. For anaircraft, the speed of wind can affect costs of air travel. When the wind ispushing the airplane towards its destination, it can reduce flight time up toseveral hours for intercontinental distances. Climate is also an influence overtransportation networks by modifying construction and maintenance costs.

A B

Absolute Barrier

A B

Relative Barrier

FrictionLow High

Detour

Modal Change

Absolute and Relative Barriers

• Absolute barriers. Geographical features that entirely prevents a movement. Theymust either be bypassed or be overcome by specific infrastructures. For instance, ariver is considered as an absolute barrier for land transportation and can only beovercome if a tunnel or a bridge is constructed. A body of water forms a similarabsolute barrier and could be overcome if ports are built and a maritime service(ferry, cargo ships, etc.) is established. Inversely, land acts as an absolute barrierfor maritime transportation, with discontinuities (barriers) than can be overcomewith costly infrastructures such as navigation channels and canals.

• Relative barriers. Geographical features that forces a degree of friction on amovement. In turn, this friction is likely to influence the path (route) selected tolink two locations (A and B on the above figure). The topography is a classicexample of a relative barrier that influences land transportation routes along pathshaving the least possible friction (e.g. plains and valleys). For maritimetransportation, relative barriers generally slow down circulation such as straits,channels or ice.

From a geometrical standpoint, the sphericity of the earth determines the great circledistance; the least distance line between two points on a sphere. This feature explainsthe paths followed by major intercontinental maritime and air routes.


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New York

Moscow

40’45”N 73’59”W

55’45”N 37’36”E

Cos (D) = (Sin a Sin b) + (Cos a Cos b Cos |c|)Sin a = Sin (40.5) = 0.649Sin b = Sin (55.5) = 0.824Cos a = Cos (40.5) = 0.760Cos b = Cos (55.5) = 0.566Cos c = Cos (73.66 + 37.4) = -0.359Cos (D) = 0.535 – 0.154 = 0.381D = 67.631 degrees1 degree = 111.32 km, so D = 7528.66 km

The Great Circle Distance

Since the Earth is a sphere, the shortest path between two points is calculated by the greatcircle distance, which corresponds to an arc linking two points on a sphere. Thecircumference inferred out of these two points divides the earth in two equal parts, thus thegreat circle. The great circle distance is useful to establish the shortest path to use whentraveling at the intercontinental air and maritime level. The great circle route follows thesphericity of the globe, any shortest route is the one following the curve of the planet, alongthe parallels.

Because of the distortions caused by projections of the globe on a flat sheet of paper, astraight line on a map is not necessarily the shortest distance. Ships and aircraft usuallyfollow the great circle geometry to minimize distance and save time and money tocustomers. For instance, the above map shows the shortest path between New York andMoscow (about 7,528 km). This path corresponds to an air transportation corridor. Airtravel over the North Atlantic between North America and Europe follows a similar path. Tocalculate the great circle distance (D) between two coordinates the following formula isused:

Cos (D) = (Sin a Sin b) + (Cos a Cos b Cos |c|)

Where a and b are the latitudes (in degrees) of the respective coordinates and |c| is theabsolute value of the difference of longitude between the respective coordinates. The resultsof this equation are in degrees. Each degree on the earth's surface equals about 111.32 km,so the result must be multiplied by this number.

2. Transportation and the Spatial Structure

All locations have a relative position in relation to each other. A primary feature is thetraditional opposition between land and water areas. This dichotomy has to a certainextent influence the development of transport means. But the relative position is notconstant as transportation developments have considerably modified accessibilitylevels. The development of geographical location reflects the cumulative connectionsbetween transport infrastructure, economic production and the built-environment. Theintroduction of new transport technology or the addition of new transport infrastructureare leading to a transformation of existing networks. Recent development in transportsystems such as container shipping, jumbo aircrafts and the extensive application ofinformation technology to land traffic management have created a new transportinfrastructure arena permitting the emergence of new production activities. These new


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and denser transport infrastructures, based on multi-layered links have intensified thenetwork character of the world economy and modified the relative location of places.The concept of spatial order is closely linked to transport geography, as withgeography in general. The degree of spatial order is related to a set of premises:

♦ Costs. The spatial distribution of activities is ordered by factors of distance,namely its friction. Locational decisions are taken in an attempt to minimizecosts, often related to transportation (the least transport cost).

♦ Accessibility. All locations have a degree of accessibility, but some areas aremore accessible than others.

♦ Agglomeration. There is a tendency for activities to agglomerate to takeadvantage of economies of scale. The organization of activities is essentiallyhierarchical, resulting from the relationships between agglomeration andaccessibility at the local, regional and global levels.

The concept of dynamics is very important to understand the relationships betweenspace and transportation, mainly through to two major spatial processes:

♦ Specialization. Linked geographical entities are able to specialize in theproduction of commodities they have a comparative advantage, while importingwhat they do not produce. As a result, efficient transportation systems aregenerally linked with higher levels of regional specialization. The globalizationof production clearly underlines this process as specialization occurs as long asthe incurred saving in production costs are higher than the incurred transportcosts.

♦ Segregation. Linked geographical entities may see the reinforcement of one atthe expense of others, notably through economies of scale. This outcome oftencontradicts regional development policies aiming at providing uniformaccessibility levels within a region.

Geographical specialization and segregation processes often occur concomitantly. Mostof contemporary transportation networks are inherited from the past, notably transportinfrastructures. Even if since the industrial revolution a set of new technologies haverevolutionized transportation in terms of speed, capacity and efficiency, the spatialstructure of many networks has not much changed. Therefore, the spatial structure oftransportation networks can be explained by two major factors:

♦ Physical attributes. Natural conditions can be modified and adapted to suithuman uses, but they are a very difficult constraint to escape, notably for landtransportation. It is thus not surprising to find that most networks follow theeasiest (least cost) and most direct path, which generally follows valleys andplains. Considerations that affected road construction a few hundred years agoare still playing today, although they are easier to circumscribe.

♦ Historical considerations. New infrastructures generally reinforce historicalpatterns of exchange, notably at the regional level. For instance, the currenthighway network of France has mainly followed the patterns set by the nationalroads network built early in the 20th century. This network was established


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over the Royal roads network, itself mainly following roads built by theRomans. At the urban level, the pattern of streets is often inherited from anolder pattern, which itself may have been influenced by the pre-existing ruralstructure (lot pattern and rural roads).

The continuous evolution of transportation technology may not necessarily haveexpected effects on the spatial structure, as two forces are at play, concentration anddispersion. A common myth tends to relates transportation solely as a force ofdispersion, favoring the spread of activities in space. This is not always the case. Innumerous instances, transportation is a force of concentration, notably for businessactivities. Since transport infrastructures are generally expensive to build, they areestablished first to service the most important locations. Even if the car was a strongfactor of dispersion, it has also favored the concentration of several activities at specificplaces and in large volumes. Shopping centers are a relevant example of this process.

3. Space / Time Relationships

One of the most basic relationship transportation has with space involves how muchspace can be overcome with a given amount of time. The faster the mode, the morespace can be purchased within the same time period. Transportation, notablyimprovements in transport systems, changes the relationship between time and space.When this relationship involves easier, faster and cheaper access between places, thisresult is defined as a space / time convergence because the amount of space that can bereached ("purchased") with a similar amount of time increases significantly. The mostsignificant regional and continental gains were achieved during the 18th and 19thcenturies, a process which went on into the 20th century. The outcome has beensignificant differences in space / time relationships, mainly between developed anddeveloping countries, reflecting differences in the efficiency of transport systems.At the international level, globalization processes have been supported byimprovements in transport technology and their spatial accumulation of transportinfrastructures. The result of more than 200 years of technological improvements hasbeen a space / time collapse of global proportions in addition to the regional andcontinental processes previously mentioned. This concomitantly shrank thetransactional space and enabled an extended exploitation of the comparativeadvantages of the global economy in terms of resources and labor. Significantreductions in transport and communication costs occurred concomitantly. Five majorfactors are to be linked with this space / time collapse:

♦ Speed. The most straightforward factor relates to the increasing speed of manytransport modes, a condition that particularly prevailed in the first half of the20th century. More recently, speed has played a less significant role as manymodes are not going much faster. For instance, a car has a similar operatingspeed today than it had 60 years ago and a commercial jet plane operates at asimilar speed than one 30 years ago.

♦ Economies of scale. Being able to transport larger amounts of freight andpassengers at lower costs has improved considerably the capacity and efficiencyof transport systems.


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♦ Expansion of transport infrastructures. Transport infrastructures haveexpanded considerably to service areas that were not serviced before or wereinsufficiently serviced. A drawback to this assertion is that although theexpansion of transport infrastructures enabled to expand distribution systems, italso expanded the number of tons-km or passengers-km considerably.

♦ Transport terminals efficiency. Terminals, such as ports and airports haveshown a growing capacity to handle large quantities of traffic over a short timeperiod.

♦ Substitution of transportation by telecommunications. It enabled severaleconomic activities to bypass the spatial constraint in a very significant manner.Electronic mail is an example where the transmission of information does nothave a physical form (outside electrons or photons) once the supportinginfrastructure is established. There is obviously a limit to this substitution, butseveral corporations are trying to use the advantages of telecommuting as muchas they can because of the important savings involved.

Trav

el Ti

me (

A–B

)

Time

T1 (1950)

T2 (2000)

∆T

∆TT

A B6.2 hours

A B2.6 hours

( )( )

yearhoursSTC

STC

TTTSTC

/072.019502000

2.66.2

−=−

−=

∆∆=

Space / Time Convergence

The space / time convergence process investigates the changing relationship between spaceand time, and notably the impacts of transportation improvements on such a relationship. Itis closely related to the concept of speed, which indicates how much space can be traveledover a specific amount of time. To measure space / time convergence (STC), travel timeinformation is required for at least two locations and two time periods. Variation in traveltime ( TT) is simply divided by the time period ( T) over which the process took place.The above figure provides an example of space / time convergence between two locations,A and B. In 1950, it took 6.2 hours to travel between A and B. By 2000, this travel time wasreduced to 2.6 hours. Consequently, STC is -0.072 hours per year, or -4.32 minutes per year.The value is negative because the time value is being reduced; if the value was positive, aspace / time divergence would be observed.

However, space / time convergence can also be inversed under specific circumstances.For instance, congestion is increasing in many metropolitan areas, implyingsupplementary delays. Traffic in congested urban areas is moving at the same speedthat in did one hundred years ago on horse carriages. Air transportation, known to havedramatically contributed to the space / time collapse is also experiencing growingdelays. Flight times are getting longer between many destinations, mainly because of


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takeoff, landing and gate access delays. Airlines are simply posting longer flight timesto factor in congestion. An express mail package flown from Washington to Boston inabout an hour (excluding delays at takeoff and landing due to airport congestion) canhave an extra one hour delay as it is carried from Logan Airport to downtown Boston, adistance of only two miles. The "last mile" can be the longest in many transportsegments. The relationships between transportation and space have changedconsiderably over the last 200 years, notably because of technological improvements.

Concept 3 – Historical Evolution of Transportation

1. Transportation in the Pre-Industrial Era (pre 1800s)

Efficiently distributing freight and moving people has always been an important factorfor maintaining the cohesion of economic systems from empires to modern nationstates. With technological and economic developments, the means to achieve such agoal have evolved considerably. The historical evolution of transportation is verycomplex and is related to the spatial evolution of economic systems. It is possible tosummarize this evolution, from the pre-industrial era to transportation in the early 21stcentury, in five major stages, each of which is linked with specific technologicalinnovations in the transport sector.Before the major technical transformations brought forward by the industrial revolutionat the end of the 18th century, no forms of mechanized transportation existed.Transport technology was mainly limited to harnessing animal labor for land transportand to wind for maritime transport. The transported quantities were very limited and sowas the speed at which people and freight were moving. The average overland speedby horse was between 8 to 15 kilometers per hour and maritime speeds were barelyabove these figures. Waterways were the most efficient transport systems available andcities next to rivers were able to trade over longer distances and maintain political,economic and cultural cohesion over a larger territory. It is not surprising to find thatthe first civilizations emerged along river systems for agricultural but also for tradingpurposes (Tigris-Euphrates, Nile, Indus, Ganges, Huang He).

The efficiency of the land transport system of this era was linked with a specificcontext of isolation and limited long distance trade. Even if the overwhelming majorityof trade was local in scope, international trade did exist and was culturally if noteconomically important, as the example of the Silk Road trade routes can testify.Traded commodities were high-value (luxury) goods such as spices, silk, wine andperfume. From the perspective of regional economic organization, the provision ofcities in perishable agricultural commodities was limited to a radius of about 50kilometers, at most. The size of cities also remained constant in time. Since people canwalk about 5 km per hour and that they are not willing to spend more than one hour perday walking, the daily space of interaction would be constrained by a 2.5 km radius, orabout 20 square kilometers. Thus, most rural areas centered around a village and citiesrarely exceeded a 5 km diameter. The largest cities prior to the industrial revolution,such as Rome, Beijing, Constantinople, or Venice never surpassed an area of 20 squarekilometers.


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Under such conditions, it was difficult to speak of an urban system, but rather of a setof relatively self-sufficient economic systems with very limited trade. Thepreponderance of city-states during this period can a priori be explained bytransportation, or rather by the difficulties of shipping goods (therefore to trade) fromone place to another. Among the most notable exceptions to this were the Roman andChinese empires, which committed extraordinary efforts at building transportationnetworks and consequently maintained control over an extensive territory for a longtime period.

♦ The Roman Empire grew around an intricate network of coastal shipping androads. Its road network supported a set of large cities around the Mediterraneanbasin. It also traded with India and China.

♦ The Chinese Empire established an important fluvial transport network withseveral artificial canals connected together to form the Grand Canal. Some partsof it are still being used today.

Guangzhou

Xi’anLanzhou

DunhuangTurpan

Hotan

KashgarSamarkand

Merv Bactra

Bukhara

ReyHamadan

Baghdad

Berenike

AlexandriaTyre

AntiochConstantinopleAthens

Rome

Muza

Aden

Kané

MuscatSur

Mogadishu

Mombasa

Barbaricon

Barygaza

Muziris

Calcutta

CHINA

INDIA

PERSIA

ARABIA

EUROPE

EGYPT

JAVA

Indian Ocean

Arabian Sea

Sout

h Ch

ina S

ea

Mediterranean Ocean

Black Sea

Caspian Sea

Gobi Desert

Taklimakan Desert

Atlantic Ocean

Paci

fic O

ceanRed Sea

SOMALIA

500 Miles

Malacca

Bay of Bengal

The Silk Road and the Arab Sea Routes

The Silk Road was the most enduring trade route of human history (being used for about1,500 years). Its name is taken from the prized Chinese textile that flowed from Asia to theMiddle East and Europe. It consisted of a succession of trails followed by caravans throughCentral Asia, about 6,400 km in length. Travel was favored by the presence of steppes,although several arid zones had to be bypassed such as the Gobi and Takla Makan deserts.Economies of scale, harsh conditions and security considerations required the organizationof trade into caravans slowly trekking from one stage (town and/or oasis) to the other.

Although it is suspected that significant trade occurred for about 1,000 years beforehand, theSilk Road opened around 139 B.C. once China was unified under the Han dynasty. It startedat Changan (Xian) and ended at Antioch or Constantinople (Istanbul), passing bycommercial cities such as Samarkand and Kashgar. It was very rare that caravans traveledfor the whole distance since the trade system functioned as a chain. Merchants with theircaravans were shipping goods back and forth from one trade center to the other.

The initial use of the sea route linking the Mediterranean basin and India took place duringthe Roman Era. Between the 1st and 6th centuries, ships were sailing between the Red Sea


16

and India, aided by summer monsoon winds. Goods were transshipped at the town ofBerenike along the Red Sea and moved by camels inland to the Nile. From that point, riverboats moved the goods to Alexandria, from which trade could be undertaken with theRoman Empire. From the 9th century, maritime routes controlled by the Arab tradersemerged and gradually undermined the importance of the Silk Road. Since ships were muchless constraining than caravans in terms of capacity, larger quantities of goods could betraded. The main maritime route started at Canton (Guangzhou), passed through SoutheastAsia, the Indian Ocean, the Red Sea and then reached Alexandria. A significant feeder wentto the Spice Islands (Mollusks) in today's Indonesia. The diffusion of Islam was alsofavored through trade as many rules of ethics and commerce are embedded in the religion.

During the Middle Ages, the Venetians controlled the bulk of the Mediterranean tradewhich connected to the major trading centers of Constantinople, Antioch and Alexandria.As European powers developed their maritime technologies from the 15th century, theysuccessfully overthrew the Arab control of this lucrative trade route to replace it by theirown. Ships being able to transport commodities faster and cheaper marked the downfall ofthe Silk Road by the 16th century.

500 km

AtlanticOcean

Red Sea

Black SeaAdriatic Sea

Mediterranean Ocean

Roman Road Network, 200 AD

The transport system of the Roman Empire was a reflection of the geographicalcharacteristics and constraints of the Mediterranean basin. The Mediterranean Oceanprovided a central role to support trade between a network of coastal cities, the mostimportant of the Empire (Rome, Constantinople, Alexandria, Cartage, etc.). These citieswere serviced by a road network permitting trade within their respective hinterlands. Littlefluvial transportation took place since the major pan-European rivers, the Rhine and theDanube, were military frontiers, not the core, of the Empire. The road served numerousfunctions, such as military movements, political control, cultural and economic (trade).

The economic importance and the geopolitics of transportation were recognized veryearly, notably for maritime transportation since before the industrial revolution, it wasthe most convenient way to move freight and passengers around. Great commercialempires were established with maritime transportation. Initially, ships were propelledby rowers and sails were added around 2,500 BC as a complementary form ofpropulsion. By Medieval times, a vast maritime trade network, the highways of thetime, centered along the navigable rivers, canals, and coastal waters of Europe (and


17

also China) was established. Shipping was extensive and sophisticated using theEnglish Channel, the North Sea, the Baltic and the Mediterranean where the mostimportant cities were coastal or inland ports (London, Norwich, Königsberg, Hamburg,Bruges, Bordeaux, Lyon, Lisbon, Barcelona, and Venice). Trade of bulk goods, such asgrain, salt, wine, wool, timber and stone was taking place. By the 14th century galleyswere finally replaced by full fledged sailships (the caravel and then the galleon) thatwere faster and required smaller crews. 1431 marked the beginning of the Europeanexpansion with the discovery by the Portuguese of the North Atlantic circular windpattern, better known as the trade winds. A similar pattern was also found on the Indianand Pacific oceans with the monsoon winds.

The fall of Constantinople, the capital of the Byzantium Empire (Eastern RomanEmpire), to the Turks in 1453 disrupted the traditional land trade route from Europe toAsia. Europe was induced to find alternate maritime routes. One alternative, followedby Columbus in 1492, was to sail to the west and the other alternative, followed byVasco de Gama in 1497, was to sail to the East. Columbus stumbled upon theAmerican continent, while Gama found a maritime route to India using the Cape ofGood Hope. These events were quickly followed by a wave of European explorationand colonization, initially by Spain and Portugal, the early maritime powers, then byBritain, France and the Netherlands. The traditional trade route to Asia no longerinvolved Italy (Venice) and Arabia, but involved direct maritime connections fromports such as Lisbon. European powers were able to master the seas with larger, betterarmed and more efficient sailing ships and thus were able to control international tradeand colonization. By the early 18th century, most of the world's territories werecontrolled by Europe, providing wealth and markets to their thriving metropolisesthrough a system of colonial trade.

0 1,000 2,000 3,000500 Miles

North Atlantic Ocean

North America

Africa

Europe

South America

West Indies

Dominant wind

Trade Route

Slaves, Gold, Pepper

Sugar, Molasses, FruitsTobacco, Furs, Indigo, Lumber1) Sugar, Molasses, Slaves

2) Flour, Meat, Lumber

Manufa

ctures

1 2

Colonial Trade Pattern, North Atlantic, 18th Century

By the early 18th century, a complex network of colonial trade was established over theNorth Atlantic Ocean. This network was partially the result of local conditions and ofdominant wind patterns. It was discovered in the 15th century, notably after the voyages of


18

Columbus, that there is a circular wind pattern over the North Atlantic. The eastward windpattern, which blows on the southern part, came to be known as the "trade winds" since theyenabled to cross the Atlantic. The westward wind pattern, blowing on the northern part,came to be known as the "westerlies".

Since sailships were highly constrained by dominant wind patterns, a trade system followedthis pattern. Manufactured commodities were exported from Europe, some towards theAfrican colonial centers, some towards the American colonies. This system also includedthe slave trade, mainly to Central and South American colonies (Brazil, West Indies).Tropical commodities (sugar, molasses) flowed to the American colonies and to Europe.North America also exported tobacco, furs, indigo (a dye) and lumber (for shipbuilding) toEurope. This system of trade collapsed in the 19th century with the introduction ofsteamships, the end of slavery and the independence of many of the colonies of theAmericas.

Prior to the industrial revolution, the quantity of freight transported between nationswas negligible according to contemporary standards. For instance, during the MiddleAges, French imports via the Saint-Gothard Passage (between Italy and Switzerland)would not fill a freight train. The total amount of freight transported by the Venetianfleet, which dominated Mediterranean trade for centuries, would not fill a moderncargo ship. The volume, but not the speed of trade improved under mercantilism (15thto 18th century), notably for maritime transportation. In spite of all, distributioncapacities were very limited and speeds slow. Examples abound; A stage wagon goingthrough the English countryside in the 16th century would do so at an average speed oftwo miles per hour. Moving one ton of cargo 30 miles (50 km) inland in the UnitedStates by the late 18th century was as costly as moving it across the Atlantic. Theinland transportation system was thus very limited, both for passengers and freight. Bythe late 18th century, canal systems started to emerge in Europe, initially in theNetherlands and England. As their maritime counterparts, they permitted the beginningof large movements of bulk freight and expanded regional trade. Maritime and fluvialtransportation were consequently the dominant modes of the pre-industrial era.

2. The Industrial Revolution and Transportation (1800-1870)

It was during the industrial revolution that massive modifications of transport systemsoccurred in two major phases, the first centered along the development of canalsystems and the second centered along railways. This period marked the developmentof the steam engine that converted thermal energy into mechanical energy, providingan important territorial expansion for maritime and railway transport systems. Much ofthe credit of developing the first efficient steam engine in 1765 is attributed to theBritish Engineer Watt, although the first steam engines were used to pump water out ofmines. It was then only a matter of time to see the adaptation of the steam engine tolocomotion. In 1769, the French engineer Cugnot built the first self-propelled steamvehicle, along with being responsible for the first automobile accident ever recorded.The first mechanically propelled maritime vehicle was tested in 1790 by the AmericanInventor Fitch as a mode of fluvial transportation on the Delaware River. This markeda new era in the mechanization of land and maritime transport systems alike.

From the perspective of land transportation, the industrial revolution was hitting abottleneck as inland distribution was unable to carry the growing quantities of rawmaterials and finished goods. Roads were commonly unpaved and could not be used to


19

effectively carry heavy loads. Although improvements were made on road transportsystems in the early 17th century, such as the Turnpike Trusts in Britain (1706) and thedevelopment of stagecoaches, this was not sufficient to accommodate the growingdemands on freight transportation. The first coach services had speeds of about 5.5miles per hour in the 1750s. From the 1760s a set of freight shipping canals wereslowly built in emerging industrial cores such as England (e.g. Bridgewater Canal,1761) and the United States (e.g. Erie Canal, 1825). These projects relied on a systemof locks enabling to overcome changes in elevation and thus linking different segmentsof fluvial systems into a comprehensive waterway system. Fluvial barges becameincreasingly used to move goods at a scale and a cost that were not possible before.Economies of scale and specialization, the foundation of modern industrial productionsystems, became increasingly applicable through fluvial canals. In 1830 there wereabout 2,000 miles or canals in Britain and by the end of the canal era in 1850, therewere 4,250 miles of navigable waterways. The canal era was however short-lived as anew mode would revolutionalize and transform inland transportation appeared in thesecond half of the 19th century.

Steam railway technology initially appeared in 1814 to haul coal. It was found thatusing a steam engine on smooth rails required less power and could handle heavierloads. The first commercial rail line linked Manchester to Liverpool in 1830 (distanceof 40 miles) and shortly after rail lines began to be laid throughout developedcountries. By the 1850s, the railroad established the first urban systems and enabled theaccess of resources and markets of vast territories, particularly from harbors. 6,000miles of railways were then operating in England and railways were quickly beingconstructed in Western Europe and North America. Finally, an inland transport systemthat was at the same time flexible in its spatial coverage and that could carry heavyloads became available. As a result many canals fell into disrepair and were closed asthey were no longer able to compete with rail services. In their initial phase ofdevelopment, railways were a point to point process where major cities were linked oneat a time by independent companies. From the 1860s, integrated railway systemsstarted to cohesively service whole nations with standard gauges and passenger andfreight services. The journey between New York and Chicago was reduced from threeweeks by stage coach to 72 hours by train. Many cities thus became closelyinterconnected. The transcontinental line between New York and San Francisco,completed in 1869, represented a remarkable achievement in territorial integrationmade only possible by rail. It reduced the journey across the continent (New York toSan Francisco) from six months to one week, thus opening for the Eastern part of theUnited States a vast pool of resources and new agricultural regions.In terms of international transportation, the beginning of the 19th century saw theestablishment of the first regular maritime routes linking harbors worldwide, especiallyover the North Atlantic between Europe and North America. These routes werenavigated by fast Clipper ships, which dominated ocean trade until the late 1850s.Composite ships (mixture of wood and iron armature) then took over a large portion ofthe trade until about 1900, but they could not compete with steamships which havebeen continually improved since they were first introduced a hundred years before.Regarding steamship technology, 1807 marks the first successful use of a steamship,Fulton's North River / Clermont, on the Hudson servicing New York and Albany. The


20

gradual improvement of steam engine technology slowly but surely permitted longerand safer voyages. In 1820, the Savannah was the first steamship (used as auxiliarypower) to cross the Atlantic, taking 29 days to link Liverpool to New York. The firstregular services for transatlantic passengers transport by steamships was inaugurated in1838, followed-up closely by the usage of the helix, instead of the paddle wheel as amore efficient propeller (1840). Shipbuilding was also revolutionalized by the usage ofsteel armatures (1860), enabling to escape the structural constraints of wood and ironarmatures in terms of ship size. Iron armature ships were 30 to 40% lighter and had15% more cargo capacity.The main consequence of the industrial revolution was a specialization oftransportation services and the establishment of large distribution networks of rawmaterials and energy.

3. Emergence of Modern Transportation Systems (1870-1920)

International transportation undertook an important phase of growth towards the end ofthe 19th century, especially with improvements in engine propulsion technology and agradual shift from coal to oil in the 1870s. Although oil has been known for centuriesfor its combustion properties, its commercial use was only applied in the early 19thcentury. Inventors started experimenting with engines that could use the cheap newfuel. Oil increased the speed and the capacity of maritime transport. It also permitted toreduce the energy consumption of ships by a factor of 90% relatively to coal, the mainsource of energy for steam engines prior to this innovation. At equal size, a oil-powered ship could transport more freight than a coal-powered ship, reducingoperation costs considerably and extending range. Further, global maritime circulationwas dramatically improved when infrastructures to reduce intercontinental distances,such as the Suez (1869) and the Panama (1914) canals were constructed. With the SuezCanal, the far reaches of Asia and Australia became more accessible.

16,000 KM

10,000 KM

Geographical Impact of the Suez Canal

Planned by the French but constructed by the British, the Suez Canal opened in 1869. Itrepresents, along with the Panama Canal, one of the most significant maritime "shortcuts"ever built. It brought a new era of European influence in Pacific Asia by reducing the


21

journey (blue line) from Asia to Europe by about 6,000 km (around Africa; red line). Theregion became commercially accessible and colonial trade expanded as a result of increasedinteractions because of a reduced friction of distance. Great Britain, the maritime power ofthe time, benefited substantially from this improved access. For instance, the Suez Canalshortened the distance on a maritime journey from London to Bombay by 41% andshortened the distance on the journey from London to Shanghai by 32%.

The increasing size of ships imposed massive investments in port infrastructures suchas piers and docks. The harbor, while integrating production and transshippingactivities, became an industrial complex around which agglomerated activities usingponderous raw materials. From the 1880s, liner services linked major ports of theworld, supporting the first regular international passenger transport services, until the1950s when air transportation became the dominant mode. This period also marked togolden era of the development of the railway transport system as railway networksexpanded tremendously and became the dominant land transport mode both forpassengers and freight. As the speed and power of locomotives improved and as themarket expanded, rail services became increasingly specialized with trains entirelydevoted to passengers or freight. Rail systems reached a phase of maturity.

Another significant technological change of this era involved urban transportation,which until then solely relied on walking and carriages. The significant growth of theurban population favored the construction of the first public urban transport systems.Electric energy became widely used in the 1880s and considerably changed urbantransport systems with the introduction of tramways (streetcars), notably in WesternEurope and in United States. They enabled the first forms of urban sprawl and thespecialization of economic functions, notably by a wider separation between the placeof work and residence. In large agglomerations, underground metro systems began tobe constructed, London being the first in 1863. The bicycle, first shown at the ParisExhibition of 1867, was also an important innovation which changed commuting in thelate 19th century. Initially, the rich used it as a form of leisure, but it was rapidlyadopted by the labor class as a mode of transportation to the workplace. Today, thebicycle is much less used in developed countries (outside for recreational purposes),but it is still a major mode of transportation in developing countries, especially China.

This era also marked the first significant developments in telecommunications. Thetelegraph is considered to be the first efficient telecommunication device. In 1844,Samuel Morse built the first experimental telegraph line in the United States betweenWashington and Baltimore, opening a new era in the transmission of information. By1852, more than 40,000 km of telegraph lines were in service in the United States. In1866, the first successful transatlantic telegraph line marked the inauguration of aglobal telegraphic network. The growth of telecommunications is thus closelyassociated with the growth of railways and international shipping. Managing a railtransport system, especially at the continental level became more efficient withtelegraphic communication. In fact, continental rail and telegraphic networks wereoften laid concomitantly. Telecommunications were also a dominant factor behind thecreation of standard times zones in 1884. From a multiplicity of local times, zones ofconstant time with Greenwich (England) as the reference were laid. This improved thescheduling of passenger and freight transportation at national levels. By 1895, everycontinent was linked by telegraphic lines, a precursor of the global information


22

network that would emerge in the late 20th century. Business transactions becamemore efficient as production, management and consumption centers could interact withdelays that were in hours instead of weeks and even months.

4. Transportation in the Fordist Era (1920-1970)

The Fordist era can be epitomized by the adoption of the assembly line as the dominantform of industrial production. The core innovation was the internal combustion engine,or four-stroke engine, which was a modified version of the Diesel engine (1885) byDaimler (1889). The invention of the pneumatic tire in 1885 by Dunlop made roadvehicles operations more comfortable, especially at high speeds. As compared withsteam engines, internal combustion engines have a much higher efficiency and areusing a lighter fuel, petrol. Petrol, initially perceived as an unwanted by-product of theoil refining process, which was seeking kerosene for illumination, became a convenientfuel. Initially, diesel engines were bulky, limiting their use to industrial and maritimepropulsion, purpose which they still fulfill today. The internal combustion enginepermitted an extended flexibility of movements with fast, inexpensive and ubiquitous(door to door) transport modes such as cars, buses and trucks. Mass producing thesevehicles changed considerably the industrial production system, notably from 1913when Ford began the production of the Model T car along an assembly line. From 1913to 1927, about 14 million Ford Model T were built, making it the second most enduringcar in the production line, behind the Volkswagen Beetle. The rapid diffusion of theautomobile marked an increased demand for oil products and other raw materials suchas steel and rubber.

With economies of scale, freight transportation was able to move low-cost bulkcommodities such as minerals and grain over long distances. Oil tankers are a goodexample of the application of this principle to transport larger quantities of oil at alower cost, especially after WWII. Maritime routes were expanded to include tankerroutes, notably from the Middle East, the dominant global producer of oil. In the1960s, tanker ships of 100,000 tons became available, to be supplanted by VLCCs(Very Large Crude Carrier) of 550,000 tons at the beginning of the 1980s. A ship of550,000 tons is able to transport 3.5 millions tons of oil annually between the PersianGulf and Western Europe.The first balloon flight took place in 1783, but due to the lack of propulsion nopractical applications for air travel were realized until the 20th century. The firstpropelled flight was made in 1903 by the Wright brothers and inaugurated the era of airtransportation. The initial air transport services were targeted at mail since it was a typeof freight that could be easily transported and initially proved to be more profitablethan transporting passengers. 1919 marked the first commercial air transport servicebetween England and France, but there were strong limitations in terms of capacity andrange. Several attempts were made at developing dirigible services, as the Atlantic wascrossed by a Zeppelin dirigible in 1924, but such a technology was abandoned in 1937with the Hindenburg accident. The 1920s and 1930s saw the expansion of regional andnational air transport services in Europe and the United States with successful propelleraircrafts such as the Douglas DC-3. The post World War II period was however theturning point for air transportation as the range, capacity and speed of aircrafts


23

increased as well as the average income of the passengers. A growing number ofpeople were thus able to afford the speed and convenience of air transportation. In1958, the first commercial jet plane, the Boeing 707, entered in service andrevolutionized international movements of passengers, marking the end of passengertransoceanic ships.Basic telecommunications infrastructures, such as the telephone and the radio, weremass marketed during the Fordist era. However, the major change of the Fordist erawas the large diffusion of the automobile, especially from the 1950s. No other modesof transportation have so drastically changed lifestyles and the structure of cities,notably for developed countries. It created suburbanization and expanded cities to areaslarger than 100 km in diameter in some instances. In dense and productive regions,such as the Northeast of the United States, the urban system became structured andinterconnected by transport networks to the point that it could be considered as onevast urban region; the Megalopolis.

5. A New Context for Transportation : the Post-Fordist Era (1970-)

Among the major changes in international transportation from the 1970s are themassive development of telecommunications, the globalization of trade, more efficientdistribution systems, and the massive development of air transportation.

Telecommunications enabled growing information movements, especially for thefinancial and service sectors. After 1970 telecommunications successfully merged withinformation technologies. As such, telecommunication also became a medium of doingbusiness in its own right, in addition to supporting and enhancing other transportationmodes. The information highway became a reality as fiber optic cables graduallyreplaced copper wire, multiplying the capacity to transmit information betweencomputers. This growth was however dwarfed by the tremendous growth in processingpower of computers, which are now fundamental components of economic and socialactivities in developed countries. A network of satellite communication was alsocreated to support the growing exchanges of information, especially for televisionimages. Out of this wireless technology emerged local cellular networks whichexpanded and merged to cover whole cities, countries, regions and then continents.Telecommunications have reached the era of individual access, portability and globalcoverage.

In a post-Fordist system, the fragmentation of the production, organizing aninternational division of work, as well as the principle of "just-in-time" increased thequantity of freight moving at the local, regional and international scales. This in turnrequired increasing efforts to manage freight and reinforced the development oflogistics, the science of physical distribution systems. Containers, main agents of themodern international transport system, enabled an increased flexibility of freighttransport, mainly by reducing transshipment costs and delays. Handling a containerrequires 25 times less labor than its equivalent in bulk freight. They were introduced bythe American entrepreneur McLean which initially applied containerization for landtransport. However, the true potential of containerization became clear when


24

interfacing with other modes became possible, mainly between maritime, rail and roadtransportation.

The first containership (The Ideal-X, a converted T2 oil tanker) set sail in 1956 fromNew York to Houston and marked the beginning of the era of containerization. TheSea-Land Company established the first regular maritime container line in 1965 overthe Atlantic between North America and Western Europe. In 1960, the Port Authorityof New York / New Jersey foreseeing the potential in container trade constructed thefirst specialized container terminal next to Port Newark; the Port Elizabeth MarineTerminal. The first international container shipping services began in 1966 between theEast Coast of the United States and Western Europe. By the early 1980s, containerservices with specialized ships (cellular containerships, first introduced in 1967)became a dominant aspect of international and regional transport systems. However,the size of those ships remained for 20 years constrained by the size of the PanamaCanal, which de facto became the panamax standard. In 1988, the first post-panamaxcontainership was introduced, an indication of the will to further expand economies ofscale in maritime container shipping.

Air and rail transportation experienced remarkable improvements in the late 1960s andearly 1970s. The first commercial flight of the Boeing 747 between New York andLondon in 1969 marked an important landmark for international transportation (mainlyfor passengers, but freight became a significant function in the 1980s). This giant planecan transport around 400 passengers, depending on the configuration. It permitted aconsiderable reduction of air fares through economies of scale and openedintercontinental air transportation to the mass market. Attempts were also undertakento establish faster than sound commercial services with the Concorde (1976; flying at2,200 km/hr). However, such services are financially unsound as no new supersoniccommercial plane was built since the 1970s and the Concorde was finally retired in2003. At the regional level, the emergence of high-speed train networks provided fastand efficient inter-urban services, notably in France (1981; TGV; speeds up to 300km/hr) and in Japan (1964; Shinkansen; speeds up to 275 km/hr).Major industrial corporations making transportation equipment, such as carmanufacturers, have become dominant players in the global economy. Even if the caris not an international transport mode, its diffusion has expanded global trade ofvehicles, parts, raw materials and fuel (mainly oil). Car production, which used to bemainly concentrated in the United States, Japan and Germany, has become a globalindustry with a few key players. Along with oil conglomerates, they pursued strategiesaimed at the diffusion of the automobile as the main mode of individual transportation.This has led the growing mobility but also to congestion and waste of energy. As of the21st century begins, the automobile accounts for about 80% of the total oilconsumption in developed countries.


25

0

5

10

15

20

25

30

35

40

1950 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000

GermanyJapanUnited StatesWorld

Automobile Production, United States, Japan and Germany, 1950-2000 (in millions)Source: WorldWatch Institute.

The last 50 years of the 20th century has seen a major shift in car production. In 1950, theUnited States accounted for more than 80% of the global car production, while this sharehas been reduced to about 14% in 2000. The United States, even if it represents the largestmarket in the world, has been thoroughly motorized. Its market is mainly one ofreplacement with acute competition between manufacturers. Roughly the same number ofcars was produced in the United States during the 1990s than during the 1950s. In the1960s, two major players emerged, Japan and Germany. They respectively accounted for20% and 13% of the global car production in 2000. A growing share of cars are beingmanufactured in newly industrialized countries, but the main consumption market stillremains the developed world and the production dominantly remained under the control ofAmerican, Japanese and German car manufacturers.

The current period is also one of transport crises, mainly because of a dual dependency.First, transportation modes have a heavy dependence on fossil fuels and second, roadtransportation has assumed dominance. The oil crisis of the early 1970s inducedinnovations in transport modes, the reduction of energy consumption and the search foralternative sources of energy (electric car, adding ethanol to gasoline and fuel cells).However, the oil counter-shock of the 1980s attenuated the importance of theseinitiatives and had few impacts on the growth of road and air transport.

6. Future Transportation

In 200 years of history since the beginning of mechanized transportation, the capacity,speed, efficiency and geographical coverage of transport systems has improveddramatically. These processes can be summarized as follows:

♦ Each mode, due to its geographical and technical specificities, wascharacterized by different technologies and different rates of innovation anddiffusion. Transport innovation can thus be an additive/consolidative forcewhere a new technology expands or makes an existing mode more efficient andcompetitive. It can also be a destructive force when a new technology marks theobsolescence and the demise of an existing mode.


26

♦ Technological innovation is linked with faster and more efficient transportsystems. This process implies a space-time convergence where a greateramount of space can be exchanged with lesser amount of time. The comparativeadvantages of space can thus be more efficiently used.

♦ Technological evolution in the transport sector is linked with the phases ofeconomic development of the world economy. Transportation and economicdevelopment are consequently interlinked as one cannot occur without theother.

100

500

1000

1800 1900 20001850 1950

50

250

750

Stage CoachRail

Automobile

TGVPropeller Plane

Jet Plane

LinerClipper Ship Containership

Road

MaritimeRail

Air

Development of Operational Speed for Major Transport Modes, 1750-2000 (km perhour)

Technological developments have two significant consequences over transportation modes.The first involves the emergence of new modes and the second concerns an improvement oftheir operational speed. Many modes follow a similar pattern where a significant growth oftheir operational speed takes place in their introduction phase. Once technical constraints aresolved and modal networks expand, the operational speed reaches a threshold whichremains until the mode becomes obsolete and is abandoned (stage coach, clipper ships andliners) or a new technology is introduced and a new wave of technical improvements incurs(jet planes, high speed trains).

Since the introduction of commercial jet planes, high-speed train networks andcontainers in the late 1960s, no significant technological change have impacted onpassengers and freight transport systems. The early 21st century is an era of car andtruck dependency, which tends to constraint the development of alternative modes oftransportation, as most of the technical improvements aim at insuring the dominance ofoil as a source of energy. However, with dwindling oil reserves, the end of thedominance of the internal combustion engine is approaching. As oil production isexpected to peak by 2008-2010 and then decline, the most important technologicaltransition in transportation since the car will take place with the introduction of fuelcells. Among the most promising technologies are:

♦ Maglev. Short for magnetic levitation, a maglev system has the advantage ofhaving no friction with its support and no moving parts, enabling to reachoperational speeds of 500-600 km per hour (higher speeds are possible if thetrain circulates in a low pressure tube). This represents an alternative for


27

passengers and freight land movements in the range of 75 to 1,000 km. Maglevimproves from the existing technology of high-speed train networks which arelimited to speeds of 300 km per hour. In fact, maglev is the first fundamentalinnovation in railway transportation since the industrial revolution. The firstcommercial maglev system opened in Shanghai in 2003 and has an operationalspeed of about 440 km per hour.

♦ Automated transport systems. Refers to a set of alternatives to improve thespeed, efficiency, safety and reliability of movements, by relying uponcomplete or partial automation of the vehicle, transshipment and control. Thesesystems could involve the improvement of existing modes such automatedhighway systems, of the creation of new modes and new transshipment systemssuch as for public transit and freight transportation.

♦ Fuel cells. An electric generator using the catalytic conversion of hydrogen andoxygen. The electricity generated can be used for many purposes, such assupplying an electric motor. Current technological prospects do not foreseehigh output fuel cells, indicating they are applicable only to light vehicles,notably cars, or to small power systems. Nevertheless, fuel cells represent a lowenvironmental impact alternative to generate energy and fuel cell cars areexpected to reach mass production by 2010. Additional challenges in the use offuel cells involve hydrogen storage (especially in a vehicle) as well asestablishing a distribution system to supply the consumers.

A fundamental component of future transport systems, freight and passengers alike, isthat they must provide increased flexibility and adaptability.

Method 1 – The Notion of Accessibility

1. Definition

Accessibility is a key element to transport geography, and to geography in general,since it is a direct expression of mobility either in terms of people, freight orinformation. Well-developed and efficient transportation systems offer high levels ofaccessibility (if the impacts of congestion are excluded), while less-developed oneshave lower levels of accessibility. Thus accessibility is linked with an array ofopportunities, let them be economic or social.

Accessibility is defined as the measure of the capacity of a location to be reachedby, or to reach different locations. Therefore, the capacity and the structure oftransport infrastructure are key elements in the determination of accessibility.

All places are not equal because some are more accessible than others, which impliesinequalities. The notion of accessibility consequently relies on two core concepts:

♦ The first is location where the relativity of places is estimated in relation totransport infrastructures, since they offer the mean to support movements.

♦ The second is distance, which is derived from the connectivity betweenlocations. Connectivity can only exist when there is a possibility to link two


28

locations through transportation. It expresses the friction of space (ordeterrence) and the location which has the least friction relatively to others islikely to be the most accessible. Commonly, distance is expressed in units suchas in kilometers or in time, but variables such as cost or energy spent can alsobe used.

There are two spatial categories applicable to accessibility problems, which areinterdependent:

♦ The first type is known as topological accessibility and is related to measuringaccessibility in a system of nodes and paths (a transportation network). It isassumed that accessibility is a measurable attribute significant only to specificelements of a transportation system, such as terminals (airports, ports or subwaystations).

♦ The second type is know as contiguous accessibility and involves measuringaccessibility over a surface. Under such conditions, accessibility is ameasurable attribute of every location, as space is considered in a contiguousmanner.

Last, accessibility is a good indicator of the underlying spatial structure since it takesinto consideration location as well as the inequality conferred by distance.

1

22

1

Distance

# of c

ente

rs# o

f cen

ters

21 2

1

2

1

# of c

ente

rs

21

A

B

C

Accessibility and Spatial Structure

Accessibility is related to the attributes of location and to distance. Due to different spatialstructures, two centers of same importance but of different locations will have differentaccessibilities. On example A representing a spatial structure where centers are uniformlydistributed, centers 1 and 2 have different accessibilities, with center 1 being the mostaccessible. As distance (Euclidean) increases, center 1 has access to a larger number ofcenters than center 2. To access all centers, center 2 would require a longer traveled distance(roughly twice) than center 1. This is particularly the case as the spatial structure changes toone concentrated around center 1 (Example B). In this case, the number of centers that canbe reached by center 1 climbs fast and then eventually peaks. The third example (C) has aspatial structure having roughly two foci. Although the number of centers that can be


29

reached from center 2 initially climbs faster than for center 1, center 1 catches up and isactually the most accessible place, but by a lesser margin.

2. Connectivity and Total Accessibility

The most basic measure of accessibility involves network connectivity where anetwork is represented as a connectivity matrix (C1), which expresses the connectivityof each node with its adjacent nodes. The number of columns and rows in this matrix isequal to the number of nodes in the network and a value of 1 is given for each cellwhere this is a connected pair and a value of 0 for each cell where there is anunconnected pair. The summation of this matrix provides a very basic measure ofaccessibility, also known as the degree of a node:

♦ C1 = degree of a node.

♦ cij = connectivity between node i and node j (either 1 or 0).

♦ n = number of nodes.

A B

D

C

E00100E

00101D

11011C

00101B

01110A

EDCBA

00100E

00101D

11011C

00101B

01110A

EDCBA

Network Connectivity Matrix

Connectivity Matrix

The network on the above figure can be represented as a connectivity matrix, which is rathersimple to construct:

Size of the connectivity matrix: involves a number of rows and cells equivalent to thenumber of nodes in the network. Since the above network has 5 nodes, its connectivitymatrix is a five by five grid.

Connection: Each cell representing a connection between two nodes receives a value of 1(e.g. Cell B - A).

Non-connection: Each cell the does not represent a connection gets a value of 0 (e.g. Cell D- E).

If all connections in the network are bi-directional (a movement is possible from node C tonode D and vice-versa), the connectivity matrix is transposable.

Adding up a row or a column gives the degree of a node. Node C is obviously to mostconnected since it has the highest summation of connectivity comparatively to every othernodes. However, this assumption may not hold true on a more complex network because ofa larger number of indirect paths which are not considered in the connectivity matrix.


30

The connectivity matrix does not however take into account all the possible indirectpaths between nodes. Under such circumstances, two nodes could have the samedegree, but may have different accessibilities. To consider this attribute, the Totalaccessibility Matrix (T) is used to calculate the total number of paths in a network,which includes direct as well as indirect paths. Its calculation involves the followingprocedure:

♦ D = the diameter of the network.Thus, total accessibility would be a more comprehensive accessibility measure thannetwork connectivity.

3. The Shimbel Index and the Valued Graph

The main focus of measuring accessibility does not necessarily involve measuring thetotal number of paths between locations, but rather what are the shortest paths betweenthem. Even if several paths between two locations exist, the shortest one is likely to beselected. Consequently, the Shimbel index calculates the minimum number of pathsnecessary to connect one node with all the nodes in a defined network. The Shimbelaccessibility matrix, also known as the D-Matrix, thus includes for each possible nodepairs the shortest path.

A B

D

C

E

A B

D

C

E

Network

00100E

00101D

11011C

00101B

01110A

EDCBA

00100E

00101D

11011C

00101B

01110A

EDCBA

C1

01E

011D

11011C

101B

1110A

EDCBA

01E

011D

11011C

101B

1110A

EDCBA

D1

C2

11011E

1

0

1

1

E

2121D

1412C

2121B

1213A

DCBA

11011E

1

0

1

1

E

2121D

1412C

2121B

1213A

DCBA

02122E

20121D

11011C

22101B

21110A

EDCBA

02122E

20121D

11011C

22101B

21110A

EDCBA

D2D

7

0

2

1

2

2

E

72122E

286465∑

6

4

6

5

∑

0121D

1011C

2101B

1110A

DCBA

7

0

2

1

2

2

E

72122E

286465∑

6

4

6

5

∑

0121D

1011C

2101B

1110A

DCBA

=1

=2

Shimbel Distance Matrix (D-Matrix)

The Shimbel Distance Matrix (or D-Matrix) holds the shortest paths between the nodes of anetwork, which are always equal or lesser to the diameter. To construct this matrix, Cmatrices of Nth order are built until the diameter of the network is reached. Each C matrix is


31

converted in a corresponding D matrix. In this case, two C matrices, C1(connectivitymatrix) and C2 (two-linkages paths; C1*C1) are built since the diameter is 2.

The first order Shimbel Matrix (D1) is a simple adaptation of C1, where all the direct linksare kept. A value of 0 is assigned for all the cii cells since the shortest path between a nodeand itself is always 0. Cells that have a value of 0 in the C1 matrix (outside cii cells) remainunfilled on the D1 matrix.

The second order Shimbel Matrix (D2) is built from the first order matrix D1 but only fromits unfilled cells. A value of 2 is assigned for each cells on the D2 matrix that have a valuegreater than 0 on the C2 matrix, but if a value of 1 already exists (D1 matrix), this value iskept. This means that on the D2 matrix of the above figure, only the values of the yellowcells have been changed to 2. Since the diameter of this network is 2, the D2 matrix is theShimbel distance matrix.

Nth order Shimbel Matrix (DN). For a network having a diameter of 3, a D3 matrix wouldhave to be built from a C3 matrix (C1*C2) because at least 1 cell would have remainedempty in the D2 matrix. Repeat the construction of Nth order Shimbel matrices until thediameter is reached.

The Shimbel Matrix (D). The order of the Shimbel distance matrix that corresponds to thediameter is the D matrix. The summation of rows or columns represents the Shimbeldistance for each node. In the D matrix of the above example, node C is having the leastsummation of shortest paths (4) and is thus the most accessible, followed by node A (5),nodes B and D (6) and node E (7). The total summation of minimal paths is 28.

The Shimbel index and its D-Matrix fail to consider that a topological link betweentwo nodes may involve variable distances. It can thus be expanded to include thenotion of distance, where a value is attributed to each link in the network. The valuedgraph matrix, or L-Matrix, represents such an attempt. It has a very strong similaritywith the Shimbel accessibility matrix and the only difference lies that instead ofshowing the minimal path in each cell, it provides the minimal distance between eachnode of the network.

A B

D

C

E

A B

D

C

E

Network

07E

01112D

711057C

5010B

127100A

EDCBA

07E

01112D

711057C

5010B

127100A

EDCBA

L1

L1 L1L2

51

0

18

7

12

14

E

511871214E

19457304343∑

57

30

43

43

∑

0111612D

11057C

165010B

127100A

DCBA

51

0

18

7

12

14

E

511871214E

19457304343∑

57

30

43

43

∑

0111612D

11057C

165010B

127100A

DCBA

57

10

711

12

=

07E

01112D

711057C

5010B

127100A

EDCBA

07E

01112D

711057C

5010B

127100A

EDCBA

07E

01112D

711057C

5010B

127100A

EDCBA

07E

01112D

711057C

5010B

127100A

EDCBA

+

Valued Graph Matrix (L-Matrix)

The construction of the valued graph matrix (L-matrix) follows the following procedure:

The distances in the network are transcribed in matrix L1 (direct connectivity distance) foreach pair directly connected. An infinite value is given for pairs not directly connected.


32

Calculation of the Nth order L matrix. The operation is similar to the creation of theShimbel Matrix. What differs in this case is that we are not working with the minimumnumber of paths, but with the minimal distance, which could give different results. Theshortest path between node A and B is obviously the A-B link. However, there is also a A-C-B link, which summation of distances could be smaller (actually it is not). The calculationof the L2 matrix requires the cross-summation of the L1 matrix where each cell in a columnis added with each cell in a row. The B-A cell on matrix L2 is thus calculated by the crosssummation of column B and row A. Only the smallest value of the five operations is kept,which is 10 in this case. Since the above network has a diameter of 2, only two steps arenecessary and the L2 matrix becomes the L-Matrix. The summation of each row on the L2matrix represents the minimal distance required to reach all the other nodes in the network.For node B, it is 43.

4. Geographic and Potential Accessibility

From the accessibility measure developed so far, it is possible to derive two simple andhighly practical measures, defined as geographic and potential accessibility.Geographic accessibility considers that the accessibility of a location is the summationof all distances between other locations pondered by the number of locations. Thelower its value, the more a location is accessible.

♦ A(G) = geographical accessibility matrix.

♦ dij = shortest path distance between location i and j.

♦ n = number of locations.

♦ L = valued graph matrix.This measure (A(G)) is an adaptation of the Shimbel Index and the Valued Graph,where the most accessible place has the lowest summation of distances.

A B

C

ED06111815E

605129D

115074C

1812708B

159480A

EDCBA

06111815E

605129D

115074C

1812708B

159480A

EDCBA

L

56

4 7

8

10.0

0

6

11

18

15

E

10.06111815E

38.06.45.49.07.2∑ /n

6.4

5.4

9.0

7.2

∑ /n

05129D

5074C

12708B

9480A

DCBA

10.0

0

6

11

18

15

E

10.06111815E

38.06.45.49.07.2∑ /n

6.4

5.4

9.0

7.2

∑ /n

05129D

5074C

12708B

9480A

DCBA

A(G)

Geographic Accessibility


33

The construction of a geographic accessibility matrix, A(G), is a rather simple undertaking:

Build the valued graph matrix (L). The above L-matrix shows the shortest distance inkilometers between five nodes (Node A to Node E).

Build the geographic accessibility matrix A(G). The A(G) matrix is similar to the L-matrixexpect that the summation of rows and columns is divided by the number of locations in thenetwork. The summation values are the same for columns and rows since this is atransposable matrix. The most accessible place is Node C, since it has the lowest summationof distances.

Although geographic accessibility can be solved using a spreadsheet (or manually forsimpler problems), Geographic Information Systems have proven to be a very usefuland flexible tool to measure accessibility, notably over a surface simplified as a matrix(raster representation). This can be done by generating a distance grid for each placeand then summing all the grids to form the total summation of distances (Shimbel)grid. The cell having the lowest value is thus the most accessible place.Potential accessibility is a more complex measure than geographic accessibility, sinceit includes simultaneously the concept of distance weighted by the attributes of a place.All places are not equal and thus some are more important than others. Potentialaccessibility can be measured as follows:

♦ A(P) = potential accessibility matrix.

♦ dij = distance between place i and j (derived from valued graph matrix).

♦ Pj = attributes of place j, such as its population, retailing surface, parking space,etc.

♦ n = number of places.The potential accessibility matrix is not transposable since locations do not have thesame attributes, which brings the underlying notions of emissiveness andattractiveness:

♦ Emissiveness is the capacity to leave a location, the sum of the values of a rowin the A(P) matrix.

♦ Attractiveness is the capacity to reach a location, the sum of the values of acolumn in the A(P) matrix.


34

A B

C

ED06111815E

605129D

115074C

1812708B

159480A

EDCBA

06111815E

605129D

115074C

1812708B

159480A

EDCBA

L

56

4 7

8

1166.4

800.0

100.0

136.4

50.0

80.0

E

1103.7133.372.744.453.3E

7695.41241.62121.31358.71807.4j

936.6

2525.7

1266.1

1863.3

i

600.0120.050.066.6D

300.01500.0214.3375.0C

75.0128.6900.0112.5B

133.3300.0150.01200.0A

DCBAi\j

1166.4

800.0

100.0

136.4

50.0

80.0

E

1103.7133.372.744.453.3E

7695.41241.62121.31358.71807.4j

936.6

2525.7

1266.1

1863.3

i

600.0120.050.066.6D

300.01500.0214.3375.0C

75.0128.6900.0112.5B

133.3300.0150.01200.0A

DCBAi\j

P(G)

800E

600D

1500C

900B

1200A

800E

600D

1500C

900B

1200A

P

1200900

1500600

800

Potential Accessibility

By considering the same valued graph matrix (L) than the previous example and thepopulation matrix P, the potential accessibility matrix, P(G), can be calculated:

The value of all corresponding cells (A-A, B-B, etc.) equals the value of their respectiveattributes (P).

The value of all non-corresponding cells equals their attribute divided by the correspondingcell in the L-matrix.

The higher the value, the more a location is accessible, node C being the most accessible.The matrix being non-transposable, the summation of rows is different from the summationof columns, bringing forward the issue of attractiveness and emissiveness. Node C has moreattractiveness than emissiveness (2525.7 versus 2121.3), while Node B has moreemissiveness than attractiveness (1358.7 versus 1266.1).

Likewise, a Geographic Information System can be used to measure potentialaccessibility, notably over a surface.

Method 2 – Geographic Information Systems for Transportation(GIS-T)1

1. Introduction

In a broad sense a Geographic Information System (GIS) is an information systemspecializing in the input, storage, manipulation, analysis and reporting of geographical(spatially related) information. Among the wide range of potential applications GIS canbe used for, transportation issues have received a lot of attention. A specific branch ofGIS applied to transportation issues, commonly labeled as GIS-T, has emerged.

1 Dr. Shih-Lung Shaw (University of Tennessee) is the major contributor of this section.


35

Geographic Information Systems for Transportation (GIS-T) refers to theprinciples and applications of applying geographic information technologies totransportation problems.

Encoding Representation model(space and data)

Management Spatial – Thematic - Temporal

Analysis Query – Operations - Modeling

Reporting Visualization and Cartography

Real World

UserTransportation Network

Flows

Land Use

Layers

Geographic Information Systems and Transportation

The four major components of a GIS, encoding, management, analysis and reporting, havespecific considerations for transportation:

♦ Encoding. Deals with issues concerning the representation of a transport system andits spatial components. To be of use in a GIS, a transport network must be correctlyencoded, implying a functional topology composed of nodes and links. Other elementsrelevant to transportation, namely qualitative and quantitative data must also beencoded and associated with their respective spatial elements. For instance, an encodedroad segment can have data related to its width, number of lanes, direction, peak hourtraffic, etc.

♦ Management. The encoded information is stored in a file structure and can beorganized along spatial (by region, country, census bloc, etc.), thematic (for road,transit, terminals, etc.) or temporal considerations (by year, month, week, etc.). Thisprocess is commonly automatic and has established conventions. For instance, manygovernment agencies use specific file formats and deploy their information along pre-determined spatial (their jurisdiction), thematic (their field of interest) and temporal(their frequency of data collection) considerations.

♦ Analysis. Considers the wide array of tools and methodologies available for transportissues. They can range from a simple query over an element of a transport system(what is the peak hour traffic of a road segment?) to a complex model investigating therelationships between its elements (if a new road segment was added, what would bethe impacts on traffic and future land use developments?).

♦ Reporting. A GIS would not be complete without all its visualization and cartographiccapabilities. This component is particularly important as it gives the possibility toconvey complex information in a symbolic format. A GIS-T thus becomes a tool toinform and convince actors who otherwise may not have the time or the capability fornon-symbolic data interpretation.

Information in a GIS is often stored and represented as layers, which are a set ofgeographical features linked with their attributes. On the above figure a transport system isrepresented as three layers related to land use, flows (spatial interactions) and the network.Each has its own features and related data.


36

GIS-T research can be approached from two different, but complementary, directions.While some GIS-T research focuses on issues of how GIS can be further developedand enhanced in order to meet the needs of transportation applications, other GIS-Tresearch investigates the questions of how GIS can be used to facilitate and improvetransportation studies [Shaw, 2002]. In general, topics related to GIS-T studies can begrouped into three categories:

♦ Data representations. How can various components of transport systems berepresented in a GIS-T?

♦ Analysis and modeling. How can transport methodologies be used in a GIS-T?

♦ Applications. What types of applications are particularly suitable for GIS-T?

2. GIS-T Data Representations

Data representation is a core research topic of GIS. Before a GIS can be used to tacklereal world problems, data must be properly represented in a digital computingenvironment. One unique characteristic of GIS is the capabilities of integrating spatialand nonspatial data in order to support both display and analysis needs. There havebeen various data models developed for GIS. The two basic approaches are object-based data models and field-based data models.

♦ An object-based data model treats geographic space as populated by discreteand identifiable objects. Features are often represented as points, lines, and/orpolygons.

♦ On the other hand, a field-based data model treats geographic space aspopulated by real-world features that vary continuously over space. Featurescan be represented as regular tessellations (e.g., a raster grid) or irregulartessellations (e.g., triangulated irregular network - TIN).

Real World

RasterVector

GIS Data Models

Representing the "real world" in a data model has been a challenge for GIS since theirinception in the 1960s. A GIS data model enables a computer to represent real geographicalelements as graphical elements. Two models of representation are possible; raster (grid-based) and vector (line-based).


37

Raster. Based on a cellular organization that divides space in a series of units. Each unit isgenerally similar in size to another. Grid cells are the most common raster representation.Features are divided into cellular arrays and a coordinate (X,Y) is assigned to each cell, aswell as a value. This allows for registration with a geographic reference system. A rasterrepresentation also relies on tessellation, which are geometric shapes that can completelycover an area. Although many shapes are possible (triangles and hexagons), the square is themost commonly used. The problem of resolution is common to raster representations. For asmall grid, the resolution is coarse but the required storage space is limited. For a large gridthe resolution is fine, but at the expense of a much larger storage space. On the above figure,the real world (shown as an aerial photograph) is simplified as a grid where each cell colorrelates to an entity such as road (red), highway (yellow) and river (blue).

Vector. The concept assumes that space is continuous, rather than discrete, which give aninfinite (in theory) set of coordinates. A vector representation is composed of three mainelements; points, lines and polygons. Points are spatial objects with no area but can haveattached attributes since they are a single set of coordinates (X and Y) in a coordinate space.Lines are spatial object made up of connected points (nodes) that have no width. Polygonsare closed areas that can be made up of a circuit of line segments. On the above figure, thereal world is represented by a series of lines (roads and highway) and one polygon (theriver).

GIS-T studies have employed both object-based and field-based data models torepresent the relevant geographic data. Some transportation problems tend to fit betterwith one type of GIS data model than the other. For example, network analysis basedon the graph theory typically represents a network as a set of nodes interconnected witha set of links. Object-based GIS data model therefore is a better candidate for suchtransportation network representations. There also exist other types of transportationdata that require extensions to the general GIS data models. One well-known exampleis linear referencing data (e.g., highway mileposts). Transportation agencies oftenmeasure locations of features or events along transportation network links (e.g., atraffic accident occurred at the 52.3 milepost on a specific highway). Such a onedimensional linear referencing system (i.e., linear measurements along a highwaysegment with respect to a pre-specified starting point of the highway segment) cannotbe properly handled by the two dimensional Cartesian coordinate system used in mostGIS data models. Consequently, the dynamic segmentation data model was developedto address this specific need of the GIS-T community. Origin-destination (O-D) flowdata are another type of data that are frequently used in transportation studies. Suchdata have been traditionally represented in matrix forms (i.e., as a two-dimensionalarray in a digital computer) for analysis. Unfortunately, the relational data modelwidely adopted in most commercial GIS software does not provide an adequate supportof handling matrix data. Some GIS-T software vendors therefore have developedadditional functions for users to work with matrix data within an integrated GISenvironment. The above examples illustrate how the conventional GIS approaches canbe further extended and enhanced to meet the needs of transportation applications.

In recent years, the development of enterprise and multidimensional GIS-T datamodels has occurred. Successful GIS deployments at the enterprise level (e.g., within astate department of transportation) demand additional considerations to embrace thediversity of application and data requirements. An enterprise GIS-T data model isdesigned to allow "each application group to meet the established needs while enablingthe enterprise to integrate and share data.". The needs of integrating 1-D, 2-D, 3-D, and


38

time for various transportation applications also have called for an implementation ofmultidimensional transportation location referencing systems.

In short, one critical component of GIS-T is how transportation-related data in a GISenvironment can be best represented in order to facilitate and integrate the needs ofvarious transportation applications. Existing GIS data models provide a goodfoundation of supporting many GIS-T applications. However, due to some uniquecharacteristics of transportation data, many challenges of developing better GIS datamodels that will improve rather than limit what we can do with different types oftransportation studies still exist.

3. GIS-T Analysis and Modeling

GIS-T applications have benefited from many of the standard GIS functions (query,geocoding, buffer, overlay, etc.) to support data management, analysis, andvisualization needs. Like many other fields, transportation has developed its ownunique analysis methods and models. Examples include shortest path and routingalgorithms (e.g., traveling salesman problem, vehicle routing problem), spatialinteraction models (e.g., gravity model), network flow problems (e.g., user optimalequilibrium, system optimal equilibrium, dynamic equilibrium), facility locationproblems (e.g., p-median problem, set covering problem, maximal covering problem,p-centers problem), travel demand models (e.g., the 4-step trip generation, tripdistribution, modal split, and traffic assignment models), and land use-transportationinteraction models.While the basic transportation analysis procedures (e.g., shortest path finding) can befound in most commercial GIS software, other transportation analysis procedures andmodels (e.g., facility location problems) are available only selectively in somecommercial software packages. Fortunately, a recent trend of moving towardscomponent GIS design in the software industry provides a better environment forexperienced GIS-T users to develop their own custom analysis procedures and models.It is essential for both GIS-T practitioners and researchers to have a thoroughunderstanding of transportation analysis methods and models. For GIS-T practitioners,such knowledge can help them evaluate different GIS software products and choose theone that best meets their needs. It also can help them select appropriate analysisfunctions available in a GIS package and properly interpret the analysis results. GIS-Tresearchers, on the other hand, can apply their knowledge to help improve the designand analysis capabilities of GIS-T.

4. GIS-T applications

GIS-T is one of the leading GIS application fields. Many GIS-T applications have beenimplemented at various transportation agencies over the last two decades. They covermuch of the broad scope of transportation, such as infrastructure planning, design andmanagement, transportation safety analysis, travel demand analysis, traffic monitoringand control, public transit planning and operations, environmental impacts assessment,hazards mitigation, and intelligent transportation systems (ITS). Each of theseapplications tends to have its specific data and analysis requirements. For example,


39

representing a street network as centerlines and major intersections may be sufficientfor a transportation planning application. A traffic engineering application, however,may require a detailed representation of individual traffic lanes. Turn movements atintersections also could be critical to a traffic engineering study, but not to a region-wide travel demand study. These different application needs are directly relevant to theGIS-T data representation and the GIS-T analysis and modeling issues discussedabove. When a need arises to represent transportation networks of a study area atdifferent scales, what would be an appropriate GIS-T design that could support theanalysis and modeling needs of various applications? In this case, it may be preferableto have a GIS-T data model that allows multiple geometric representations of the sametransportation network. Research on enterprise GIS-T data model andmultidimensional, multimodal GIS-T data model discussed above aims at addressingthese important issues of better integrating various GIS-T applications.With the rapid growth of the Internet and wireless communications in recent years, agrowing number of Internet-based and wireless GIS-T applications can be found. Suchapplications are especially common for ITS and for location-based services (LBS).Another trend observed in recent years is the growing number of GIS-T applications inthe private sector, particularly for logistics applications. Since many businesses involveoperations at geographically dispersed locations (e.g., supplier sites, distributioncenters/ warehouses, retail stores, and customer sites), GIS-T can be useful tools for avariety of logistics applications. Again, many of these logistics application are basedon the GIS-T analysis and modeling procedures such as the routing and the facilitylocation problems.GIS-T is interdisciplinary in nature and has many possible applications. Transportationgeographers, who have appropriate backgrounds in both geography and transportation,are well positioned to pursue GIS-T studies.

TG Chapter 1

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