Jean-Paul Rodrigue (2013), New York:
Routledge, 416 pages.
Authors: Dr. Jean-Paul Rodrigue and Dr. Brian Slack
1. The Setting of Road Transport Systems
Two major modes are composing the land transport system, roads and
railways. Obviously, roads were established first, as rail technology
only became available by the 18th century, in the midst on the industrial
revolution. Historical considerations are important in assessing the
structure of current land transportation networks. Modern roads tend
to follow the structure established by previous roads, as it was the
case for the modern European road network (especially in Italy, France
and Britain) that follows the structure established by the Roman road
network centuries before.
The first land roads took their origins from
trails which were generally used to move
from one hunting territory to another. With the emergence of the first
forms of nation-states trails started to be used for commercial purposes
as trade expanded and some became roads, especially through the
of animals such as horses, mules and camels. The use of wheeled vehicles
encouraged construction of better roads to support the additional weight.
However, a road transport system requires a level of labor organization
and administrative control that could only be provided by a form of
governmental oversight offering some military protection over trade
routes. By 3,000 BC the first paved road systems appeared in Mesopotamia and
asphalt was used to pave roads in Babylon by 625 BC. The Persian Empire
had a road of 2,300 km in the 5th century BC. However, the first major
road system was established by the Roman Empire
from 300 BC and onwards, mainly for economic, military and administrative
reasons. It relied on solid road engineering methods, including the
laying of foundations and the construction of bridges. This was also
linked with the establishment of pan-continental trading routes, such
as the Silk Road, linking
Europe and Asia by 100 BC.
Following the fall of the Roman Empire in the 5th century, integrated
road transportation fell out of favor as most roads were locally constructed
and maintained. Because of the lack of maintenance of many road segments,
land transport became a very hazardous activity. It is not until the
creation of modern nation-states in the 17th century that national
road transportation systems were formally established. In the 18th
century, the French, through
central government efforts, build their Royal Roads system spanning
24,000 km, over which a public transport service of stage-coaches carrying
passengers and mail was established. The British, mainly through private
efforts, built a 32,000 km
system of turnpikes
where tolls have to be paid for road usage. A similar initiative was
undertaken in the United States in the 19th century and by the early
20th century, a network of 3 million km of roads, most unpaved, was
in operation. 1794 marks the beginning of modern road transportation
with the first mail coach service between London and Bristol, operating
under a timetable.
Also of high significance were technological innovations in road
engineering that permitted the construction of reliable and low cost
hard surface roads. One such achievement came from the Scottish engineer
McAdam who developed a process (later known as
macadam) where hard and waterproof road surfaces
were made by cemented crushed stone, bound together either with water
or with bitumen. It provided a cheaper, durable, smooth and non-slippery
pavement, which considerably improved the reliability and the travel
speed on roads. Many roads could now be used year round.
Road development accelerated in the first half of the 20th century.
By the 1920s, the first all-weather transcontinental highway, the Lincoln
Highway, spanned over 5,300 km between New York and San Francisco.
However, it was simply a set of connected roads. Germany was the first to build the modern highway (autobahn)
in 1932 with specifications such as restricted access, overpasses and
road separation that would eventually become common characteristics
of modern highway systems. The post-World War Two era represented a period
of rapid expansion of road transportation networks worldwide.
remarkable road transport achievement is without doubt the
setting of the
American Interstate highway system
initiated in 1956. Its strategic purpose was to provide a national road
system servicing the American economy and also able to support troop
movements and act as air strips in case of an emergency. About 56,000
km were built from the 1950s to the 1970s, but between 1975 and 2006
only 15,000 km were added to the system, underlining growing construction
costs and diminishing returns.
Overall, about 70,000 km of four-lane and six-lane highways were constructed,
linking all major American cities, coast to coast. A similar project
took place in Canada with the Trans-Canada highway completed in 1962.
By the 1970s, every modern nation has constructed a national highway
system, which in the case of Western Europe resulted in a pan-European
system. This trend now takes place in many industrializing countries.
For instance, China is building a national highway system that expanded
to 104,000 km in 2013, with construction
taking place at a pace of about 2,000 km per year.
2. The Spatial Impacts of Road Transportation
Road transportation is the mode that has
expanded the most over the last 50 years,
both for passengers and freight transportation. This represents a
dramatic change in the built environment with the massive addition of
road infrastructures. The spatial cover of road transportation is
extensive. Growth in road
freight transport has been fueled largely by trade liberalization as
modal shares of trade within the European Union and
NAFTA suggest. This is the result of growth of
the loading capacity of vehicle and an adaptation of vehicle to freight
(e.g. perishables, fuel, construction materials, etc.) or passengers
(e.g. school bus) demand for speed, autonomy and flexibility. New
types of problems, such as a significant growth of fuel
consumption, increasing environmental externalities, traffic
congestion and a safety (accidents) have also emerged.
Roads have a functional hierarchy depending on the
role they play in the network. At the top of the hierarchy are freeways
(highways), which are limited access roads with no intersections. There
are also arterials that are roads that have traffic signals at
intersection, forcing vehicles to stop. These arterials are fed by
collectors and local roads, which have the main purpose to connect
specific activities (residences, retail stores, industries). Put
together, this network enables point to point services, a notable
advantage the road transport has over other transport modes. Road transport modes have limited potential to achieve economies
of scale. This is due to size and weight constraints imposed by
governments and also by the technical and economic limits of engines.
In most jurisdictions, trucks and busses have specific weight and length
restrictions which are imposed for safety reasons. While in the
United States, the maximum gross vehicle weight is 36 metric tons
(80,000 pounds), while in Europe and China these figures are 40
(88,000 pounds) and 49 (100,000 pounds) metric tons respectively. In addition, there
are serious limits on the traction capacities of cars, buses and trucks
because of the considerable growth in energy consumption that accompany
increases in the vehicle weight. For these reasons the carrying capacities
of individual road vehicles are limited.
Road transportation is characterized by acute geographical disparities
in traffic. It is not uncommon that 20% of the road network supports
60 to 80% of the traffic. This observation is expanded by the fact
that developed and developing countries have important
differences in terms of the density,
capacity and the quality of road transport infrastructures. Acute geographical
variations of the inventory are therefore the norm.
Technological evolution of road transport vehicles was a continuous
trend since the first automobiles were built. The basic technology
is however very similar, as road transportation massively relies on
the internal combustion engine. In the future new materials (ceramic,
plastic, aluminum, composite materials etc...), fuels (electricity,
hydrogen, natural gas, etc...) and information technologies (vehicle control,
location, navigation and toll collection) are expected to be included
in cars and improve the efficiency of road transport systems. There
are however signs that a peak mobility
can be achieved for road transportation when the car has been diffused
to some optimum level and that countervailing forces are at play such
as congestion, the aging of the population or a decline in income. A
similar pattern of
peaking truck circulation is emerging in large metropolitan areas.
The urban population has increased considerably over the last 50
years and about 50% of the global population was urbanized by 2010 (about
3.5 billion people). It is challenging for developing countries to have
a rates of individual vehicle ownership similar to those of developed
countries, especially compared with the United States, not
because of a lack of income, but the physical lack of space to
accommodate a high level of car ownership. This will
impose new or alternative methods to transport freight and passengers
over urban roads. The reduction of vehicle emissions and the
impacts of infrastructures on the environment are mandatory to promote
a sustainable environment. Under such circumstances
cycling is thus to be considered an
alternative to the automobile in urban areas,
widely adopted in developing countries,
although more for economic reasons. However, the potential of cycling is
related to its substitution for existing public transit users. There is
limited potential to substitute car trips by bicycle trips since most
car trips cover longer distances that are not easily substitutable by
other modes, including the bicycle. Bicycle parking schemes at urban
transit stations are a strategy that can be used as a strategy to incite
Road transport, however, possesses significant advantages
over other modes:
These multiple advantages have made cars, buses and trucks the modes of
choice for a large number of trip purposes, and have led to their
dominance for short distance trips. The success of cars and trucks
has given rise to a number of serious problems. Road congestion has
become a feature of most urban areas around the world. In addition, the
mode is behind many of the major environmental externalities linked to
transportation. Addressing these issues is becoming an important policy
challenge at all levels of jurisdiction, from the local to the global. A
symbiosis between types of roads and types of traffic with
specialization (reserved lanes and hours) is to be expected.
3. Infrastructures and Investments
Road infrastructures are moderately expensive to provide,
but there is a wide divergence of costs, from a gravel road to a multi-lane
urban expressway. Because vehicles have the means to climb moderate
slopes, physical obstacles are less important than for some other land
modes, namely rail. Most roads are provided as a public good
by governments, while the vast majority of vehicles are owned privately.
Capital costs, therefore, are generally assumed by the society, and
do not fall as heavily on one source as is the case for other modes.
Unlike many transport infrastructures where the network is paid for
by the user through a pricing mechanism, 95% of the financing of
road infrastructure is covered by the public sector, leaving the
reminder covered by tolls. Road transportation thus has a unique
characteristic where several costs are externalized. This is an indirect
form of mobility subsidy.
The public offering of free road infrastructure conveys several advantages to the private sector, but can also
lead to serious problems. The main advantage is clear; the users of
roads commonly do not bear the full operating costs implying
that road transportation tends to be below real market price. For
road freight transportation, this can be seen as a subsidy as road maintenance
is not part of the operating costs,
but is indirectly present with taxes and tolls. As long as there is
spare road capacity this situation works for the benefit of the
However, when congestion starts to arise, users have limited, if any,
influence on the construction of new and improved infrastructure to
mitigate the problem since they do not own the infrastructure and are
using it for free. Lobbying public entities to receive public road infrastructure
investments can be a very long process, subject to constant delays and
changes. Road users thus become trapped in a situation they can do little
to change since it is provided free of charge. This can be labeled as
the "free roads curse". An entity owning and operating its own
network, such as a rail company in North America, has the advantage
of directly implementing improvements with its own capital if congestion
arise on a segment of its network. It is thus better placed to cope
Governments can expropriate the necessary land for road construction
since a private enterprise may have difficulties to expropriate without
government support. Another important aspect about roads is their
economies of scale and their indivisibility, underlining
that the construction and maintenance of roads is cheaper when the system
is extensive, but to a limit. However, all road transport modes have
limited abilities to achieve scale economies. This is due to the size
constraints imposed by governments and also by the technical and economic
limits of the power sources and what infrastructures can bear weight-wise.
In most jurisdictions, trucks and busses have specific weight and length
restrictions which are imposed for safety reasons. In addition, there
are serious limits on the traction capacities of cars, busses and trucks
because of the considerable increases in energy consumption that accompany
increases in the weight of the unit. For these reasons the carrying
capacities of individual road vehicles are limited. Roads are thus costly
infrastructures, but also sources of revenue:
- The capital cost of vehicles is relatively small,
which makes it comparatively easy for new users to gain entry.
This helps ensure that the trucking industry, for example, is highly
competitive. Low capital costs also ensure that innovations and
new technologies can diffuse quickly through the industry.
- Another advantage of road transport is the high relative
speed of vehicles, the major constraint being government-imposed
- One of its most important attributes is the flexibility of
route choice, once a network of roads is provided. Road transport
has the unique opportunity of providing door to door service for
both passengers and freight.
In many cases governments have been inefficient custodians of road
infrastructure as it is tempting to delay road maintenance
or improvements because of the high costs involved. Budgetary problems are also inciting selling assets
to increase revenue and reduce expenses. Consequently, a growing number
of roads have been privatized and companies specializing in road
management have emerged, particularly in Europe and North America. This
is only possible on specific trunks that have an important and stable
traffic. Private enterprises usually have vested interests
to see that the road segments they manage are maintained and improved
since the quality of the road will be directly linked with revenue generation.
The majority of toll roads are highways linking large cities or bridges
and tunnels where there is a convergence of traffic. Most roads are
not economically profitable but must be socially present as they
are essential to service populations.
- Costs. They include rights of way, development costs
(planning), construction costs, maintenance and administration costs,
losses in land taxes (urban environment), expropriation costs (money
and time), and external costs (accidents and pollution).
- Revenue. They include registration, gas (taxes),
purchases of vehicles (taxes), tolls, parking, and insurance fees.
Another form of indirect income concerns traffic violations (e.g.
speeding) that are using the pretext of public safety to hide revenue
generation practices by local governments.