Jean-Paul Rodrigue (2013), New York:
Routledge, 416 pages.
Authors: Dr. Jean-Paul Rodrigue and Dr. Claude Comtois
Transport geography is concerned with movements that take place over
space. The physical features of this space impose major constraints
on transportation systems, in terms of what mode can be used, the
extent of the service, its costs, capacity and reliability. Three basic
spatial constraints of the
terrestrial space can be identified:
From a geometrical standpoint, the sphericity of the earth determines
great circle distance; the least distance line between two
points on a sphere. This feature explains the paths followed by major
intercontinental maritime and air routes.
2. Overcoming the Physical Environment
Rapid technological developments have enabled transportation to overcome the physical environment.
Before the Middle Ages, road location have been adapted to topography.
Since then, efforts have been made to paving roads, bridging rivers
and cutting paths over mountain passes. Engineering techniques in terms
of arch and vault used in Byzantine and Gothic church constructions
in the twelfth century permitted bridge building across wider streams
or deep river valleys. Road building has been at the core of technological
efforts to overcome the environment. Roads have always been the support
for local and even long distance travel. From the efforts to mechanize
individual transport to the development of integrated highways, road
building has transformed the environment. Land transportation was further
facilitated with the development of technical solutions for preventing
temporary interruptions in road transport provision through routeways
protection. More recently, the development of road transport
and the growth in just-in-time and door-to-door services have increased
engineering demands for constructing multi-level and high speed highways.
Innovations in maritime transport can be found around the world.
The earliest developments came in the transformation of waterways for
transportation purposes through the development of canal locks
coping with adverse
natural gradients. Further improvements in navigation came with the cutting of
artificial waterways. Some of the earliest examples can be found in
the Dutch canal, the Martesana canals of Lombardy, the canal de Briare
in France or the Imperial canal of China. Further improvements in navigation
technology and the nature of ships permitted to increase the speed,
range and capacity of ocean transport. But the increasing size of ships
has resulted in excluding canals such as Panama from servicing
the largest, modern and efficient world’s maritime carriers. Several
canal authorities have thus embarked in expansion programs. Increasing attention has also been
paid to creating new passages between semi-enclosed seas. In Canada
and Russia, the growing competition between the sea and land corridors
are not only reducing tariffs and encouraging international trade but
prompting the governments to reassess traditional ocean connections.
Passages through the Arctic Ocean are being investigated with a
view to create new international connections. Artificial islands are
also created to permit port installations in deep waters.
In China, it became clear that dredging the Yangzi River Delta was
insufficient to insure the competitiveness of the port of Shanghai.
The development of a new port site in Hangzhou Bay and the modification
of the Yangshan islands landscape have become indispensable.
As level ground over long distance is important for increasing the
efficiency of railway routes, the transport industry has come to modify
the earth’s features by building bridges and tunneling, by embanking
and drainage. From medieval Germany to France’s high speed TGV, increasing
motive power has permitted physical obstacles to be overcome.
The role of technology has been determinant in the development of
the air transport sector. From the experiments of the Montgolfier brothers
to the advent of jet aircraft, aerial crossing of rugged terrain over
considerable distance became possible. Technical innovation in the aeronautic
industry has permitted planes to avoid adverse atmospheric conditions,
improve speed, increase stage length and raise carrying capacity. With
the rapid rise in air passenger and freight transport, emphasis has
been given to the construction of airport terminals and runways. As
airports occupy large areas, their environmental imprint is important.
The construction of Chek Lap Kok airport in Hong Kong led to leveling
mountainous land for the airport site. Kansai airport servicing Osaka
has been built on an artificial island.
3. Transportation and the Spatial Structure
The concepts of
site and situation are fundamental to geography and to transportation.
While the site refers to the geographical characteristics of a specific
location, its situation concerns its relationships in regard to other
locations. Thus, all locations are relative to one another but situation
is not a constant attribute as transportation developments change levels
of accessibility, and thus the relations between locations. The development
of a location reflects the cumulative relationships between transport
infrastructure, economic activities and the built-environment. The following
factors are particularly important in shaping the
- Topography: Features such as mountains and valleys have
strongly influenced the structure of networks, the cost and feasibility
of transportation projects. The main land transport infrastructures
are built usually where there are the least physical impediments,
such as on plains, along valleys, through mountain passes, or
when absolutely necessary through the digging of tunnels. Water
transport is influenced by water depths and the location of obstacles
such as reefs. Coastlines exert an influence on the location of
port infrastructure. Aircraft require airfields of considerable
size for take off and landing. Topography can impose a natural convergence
of routes that will create a certain degree of centrality and may
assist a location in becoming a trade center as a collector and
distributor of goods. Topography can complicate, postpone or prevent
the activities of the transport industry. Physical constraints fundamentally
absolute and relative barriers to movements. An absolute
barrier is geographical feature that entirely prevent a movement
while relative barriers impose additional costs and delays. Land transportation
networks are notably influenced by the topography, as highways and
railways tend to be impeded by grades higher than 3% and 1% respectively.
Under such circumstances, land transportation tends to be of higher
density in areas of limited topography.
- Hydrology: The properties, distribution and
of water play an important role in the transport industry. Maritime
transport is influenced greatly by the availability of
navigable channels through rivers, lakes and shallow seas. Several
rivers such as the Mississippi, the St. Lawrence, the Rhine, the
Mekong or the Yangtze are important navigable routes into the
heart of continents and historically have been the focus of human
activities that have taken advantage of the transport opportunities.
Port sites are also highly influenced by the physical attributes
of the site where natural features (bays, sand bars, and fjords)
protect port installations. Since it is at these installations that
traffic is transshipped, the location of ports is a dominant element
in the structure of maritime networks. Where barriers exist, such
as narrows, rapids, or land breaks, water transport can only overcome
these obstacles with heavy investments in canals or dredging. Conversely
waterways serve as barriers to land transportation necessitating
the construction of bridges, tunnels and detours etc.
- Climate: Its major components include temperature,
wind and precipitation. Their impacts on transportation modes
and infrastructure range from negligible to severe. Freight and
passenger movement can seriously be curtailed by hazardous conditions
such as snow, heavy rainfall, ice or fog. Air transportation is
particularly vulnerable to weather disruptions, such as
during winter when a snow storm can create cascading effects. Jet streams are also a
major physical component that international air carriers must take
into consideration. For an aircraft, the speed of wind can affect
travel costs. Tailwind conditions can reduce flight time up to several hours for intercontinental
flights. Climate is also an influence over transportation networks
by influencing construction and maintenance costs. Even volcanic
eruptions can have an impact as it was the case in 2010 when a
volcanic eruption in Iceland released large amounts of
the atmosphere which forced the closing of most airports in
northwestern Europe as well as the cancellation of many transatlantic flights out of
concern that the ash could damage jet engines.
Many contemporary transportation networks are inherited from the
past, notably transport infrastructures. Even if over the last two hundred
years new technologies have revolutionized transportation in terms of
speed, capacity and efficiency, the spatial structure of many networks
has not much changed. This inertia in the spatial structure of
some transportation networks can be explained by two major factors:
- Costs. The spatial distribution of activities is related
to factors of distance, namely its friction. Locational decisions
are taken in an attempt to minimize costs, often related to transportation.
- Accessibility. All locations have a level of accessibility,
but some are more accessible than others. Thus, because of transportation,
some locations are perceived as more valuable than others.
- Agglomeration. There is a tendency for activities to
agglomerate to take advantage of the value of specific locations.
The more valuable a location, the more likely agglomeration will
take place. The organization of activities is essentially hierarchical,
resulting from the relationships between agglomeration and accessibility
at the local, regional and global levels.
While physical and historical considerations are at play, the introduction
of new transport technology or the addition of new transport infrastructure
may lead to a transformation of existing networks. Recent developments
in transport systems such as container shipping, jumbo aircrafts and
the extensive application of information technology to transport management
have created a new transport environment and a new spatial structure.
These transport technologies and innovations have intensified global
interactions and modified the relative location of places. In this highly
dynamic context, two processes are taking place at the same time:
- Physical attributes. Natural conditions can be modified
and adapted to suit human uses, but they are a very difficult constraint
to escape, notably for land transportation. It is thus not surprising
to find that most networks follow the easiest (least cost) paths,
which generally follow valleys and plains. Considerations that affected
road construction a few hundred years ago are still in force today,
although they are sometimes easier to circumscribe.
- Historical considerations. New infrastructures generally
reinforce historical patterns of exchange, notably at the regional
level. For instance, the current highway network of France has mainly
followed the patterns set by the national roads network built early
in the 20th century. This network was established over the Royal
roads network, itself mainly following roads built by the Romans.
At the urban level, the pattern of streets is often inherited from
an older pattern, which itself may have been influenced by the pre-existing
rural structure (lot pattern and rural roads).
The continuous evolution of transportation technology may not necessarily
have expected effects on the spatial structure, as two forces are at
play; concentration and dispersion. A common myth tends
to relate transportation solely as a force of dispersion, favoring the
spread of activities in space. This is not always the case. In numerous
instances, transportation is a force of concentration and clustering, notably for business
activities. Since transport infrastructures are generally expensive
to build, they are established first to service the most important locations.
Even if it was a strong factor of dispersion, the automobile has also
favored the concentration of several activities at specific places and
in large volumes. Shopping centers are a relevant example of this process
where central locations emerge in a dispersed setting.
4. Space / Time Relationships
One of the most basic relationships of transportation involves how
much space can be overcome within a given amount of time. The faster
the mode, the larger is the distance that can be overcome within the
same amount of time. Transportation, notably improvements in transport
systems, changes the relationship between time and space. When this
relationship involves easier, faster and cheaper access between places,
this result is defined as a
space / time convergence because the amount of space that can be
overcome for a similar amount of time increases significantly. It is
however a spatially and socially uneven process since it will impact the
accessibility of locations differently. For instance, infrastructure
will not be laid up uniformly and segments of the population will
experience a greater improvement in mobility because of their
socioeconomic status (e.g. business people). In spite of these uneven
regional and continental gains were achieved during the 18th and
19th centuries with the establishment of national and continental railway
systems as well as with the growth of maritime shipping, a process which
continued into the 20th century with air and road transport systems.
The outcome has been
significant differences in space / time relationships, mainly between
developed and developing countries, reflecting differences in the efficiency
of transport systems.
At the international level, globalization processes have been supported
by improvements in transport technology. The result of more than 200
years of technological improvements has been a
space / time convergence of global proportions in addition to the
regional and continental processes previously mentioned. This enabled
the extended exploitation of the advantages of the global market, notably
in terms of resources and labor. Significant reductions in transport
and communication costs occurred concomitantly. There is thus a relationship
between space / time convergence and the integration of a region in
global trade. Five major factors are of particular relevance in this
Specialization. Linked geographical entities are able to specialize
in the production of commodities for which they have an advantage,
and trading for what they do not produce. As a result, efficient
transportation systems are generally linked with higher levels of
regional specialization. The globalization of production clearly
underlines this process as specialization occurs as long as the
incurred savings in production costs are higher than the incurred
additional transport costs.
Segregation. Linked geographical entities may see the reinforcement
of one at the expense of others, notably through economies of scale.
This outcome often contradicts regional development policies aiming
at providing uniform accessibility levels within a region.
Yet, space / time convergence does not occur in a ubiquitous
manner. In time, some locations gain more accessibility than others
particularly if they experience the accumulation of transport
infrastructures. After centuries of transport developments and their
impacts on geography, global
accessibility reflects a heterogeneous geography. Space / time convergence can also be inverted under
specific circumstances, which means that a process of space / time divergence
takes place. For instance, congestion is increasing in many metropolitan
areas, implying additional delays for activities such as
commuting. Traffic in congested urban areas is moving at the same
speed that it did one hundred years ago on horse carriages. Air transportation,
despite having dramatically contributed to the space / time convergence
is also experiencing growing delays. Flight times are getting longer
between many destinations, mainly because of takeoff, landing and gate
access delays. Airlines are simply posting longer scheduled flight times to factor
in congestion. The termination of the Concorde supersonic jet
service in 2003 can also be considered as a space / time divergence. More stringent
security measures at airports have also imposed additional delays, which
tends to penalize short distance flights. Additionally, direct
transport services can be discontinued and replaced by a hub-and-spoke
structure. The "last mile" can be
the longest in many transport segments. For instance, an express
mail package flown from Washington to Boston in about an hour (excluding
delays at takeoff and landing due to airport congestion) can have an
extra one hour delay as it is carried from Logan Airport to downtown
Boston, a distance of only two miles.
- Speed. The most straightforward factor relates to the
increasing speed of many transport modes, a condition that particularly
prevailed in the first half of the 20th century. More recently,
speed has played a less significant role as many modes are not going
much faster. For instance, an automobile has a similar operating
speed today than it had 60 years ago and a commercial jet plane
operates at a similar speed than one was 30 years ago.
- Economies of scale. Being able to transport larger amounts
of freight and passengers at lower costs has improved considerably
the capacity and efficiency of transport systems. For space -
time convergence this implies that there is more capacity for a
given quantity of passengers or freight being carried. Instead,
the traffic can be handled with fewer trips implying that at the
aggregate level it is moving faster.
- Expansion of transport infrastructures. Transport infrastructures
have expanded considerably to service areas that were not previously
serviced or were insufficiently serviced. A paradox of this feature
is that although the expansion of transport infrastructures may
have enabled distribution systems to expand, it also increased the
average distance over which passengers and freight are being carried.
- Efficiency of transport terminals. Terminals, such as
ports and airports, have shown a growing capacity to handle large
quantities in a timely manner. Thus, even if the speed of many transport
modes has not increased, more efficient transport terminals and
a better management of flows have helped reduce transport time.
- Information technologies (IT).
Enabled several economic activities to bypass spatial constraints
in a very significant manner as IT supports complex management
structures. Electronic mail is an example where
the transmission of information does not have a physical form (outside
electrons or photons) once the supporting infrastructure is established.
There is obviously a limit to this substitution, but several corporations
are trying to use the advantages of telecommuting as much as they
can because of the important savings involved.