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Social and environmental sustainability of an urban transportation system

Term Paper

The world population has been increased by five billion in fifty years, and

many other parameters such as industrialization have increased the urbanization rate up to

80% in developed countries, with a mean rate of 50% over the world. Another tendency that

can be observed is global warming, and those two issues are closely linked together since it

is mostly due to greenhouse gas emissions. With more and more people living in cities, new

challenges in transportation have been raised and there is a need to develop urban

transportation systems that will both be environmentally sustainable and answer social

needs. Inhabitants expect to have access to a mean of transport fast, safe, convenient,

punctual and economic to go from one place to another, and the goal that has to be reached

is to reduce dramatically the use of the car and to respond to these expectations. Moreover,

the transportation system has to be integrated in the city with respect to the importance of its

different places. Those considerations lead to the question: What constitute a socially and

environmentally sustainable urban transportation system and how can we implement it? To

try to answer this interrogation, we will first consider how to build a socially sustainable

system after looking for the meaning of social sustainability. We will then look for the

characteristics of an environmentally sustainable mean of transportation. In a third part, we

will consider the example of Ottawa and more generally of existing systems, and define the

methods of selection and funding for new projects.

First of all, a transportation system is developed to match expectations and

needs of the inhabitants of the city. As a matter of fact, it is a characteristic of a space of

high demographic concentration, and is clearly related to social interactions since its goal is

to help people to go from one place to another, and more specifically to permit people to

reach their jobs and other activities of the social life. This section tends to present the social

expectations towards a transportation system.

Urbanization is a tendency that has been accelerated over the past few decades to

reach about 80% in most developed countries. It started when cities became centers of

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production, but the evolution of pedestrian and mercantile cities into the cities that we know

today is almost entirely due to the industrial revolution. The growth of industries in the urban

area created new jobs opportunities, so it attracted people and created new livelihoods.

Combined with the dramatic increasing of the population, this phenomenon results in the

appearance of huge urban areas. Later, the development of transportation means initiated

the appearance of suburbs, offering at first a mean of escaping the city’s drawbacks. But in

many cities the population continued to increase, so the cities continued to spread out with

low density suburbs, and the transportation system now faces new challenges. Even people

living far from the center where the social activities, jobs, and most commercial activities

take place, expect to be able to reach those activities. This means that the urban planners

have to provide them with a mean of transportation which will permit them to go easily from

one place to another. The inhabitants expect this mean to be fast, that is to say that the

travel time between two points has to be minimized. To do so, the network shall be dense so

each point of the city can be easily reached, which can be difficult in large urban areas.

There is also a need for good concordance between the time of arrival and departure of

each mode of transport to make connections easier. Then, the punctuality of the different

means also enters in consideration, for instance the system has to deal with the traffic

usually related to big urban areas but also be well run in term of ridership so that it is not

slowed down on peak time. Moreover, the transportation system has to be safe and cheap

(Zheng and Fu, 2004). All those objectives may be difficult to reach in spread out areas, but

the spreading out is not the only challenge of urban forms. As a matter of fact, in many cities

we can observe differences of development regarding different neighborhoods. It can be

either because of land use or because of segregation. Land use designs the different use of

land that can be made in urban areas. For example, it can be industrial along transportation

routes, residential on the side of the industrial area – as a place where workers dwell-, closer

to the central business district or further for high-rent sectors. People with low income will

tend to dwell near industrial areas, wastes facilities, etc., because the surrounding property

value have declined. In addition, the theory of zoning in some cities such as New York

enhances the specification of land for determined purpose. Environmental racism together

with segregation that forced certain minorities to live in peculiar areas contributed to create

districts that won’t be considered in the same way by the municipality. Hence, people living

in distinct areas won’t have access to the same opportunities, and the study of accessibility

as ease of reaching a particular area of activity provides evidences of that fact, and can help

for the formulation of adequate responses (Bocarejo and Oviedo, 2012).

Those challenges of modern urban areas make us wonder about inequities and

social exclusion as a result of lack of public transportation, or at least unequal repartition of

this system. We may wonder which part of the population is more penalized and how social

exclusion takes place. The link between inequities and transportation is particularly

important in Australia, where cities have the lowest density in the world. Inequities in access

to social activities has been observed mostly among young people, seniors, people with

impairment, minorities and people with low income (Currie, 2009). Regarding Australian

cities, it is linked to a lack of access to a car, but the considerations can be extended to the

lack of any mean of transportation that should replace the car. Without any transportation

system, young people, often seeking independence, won’t be able to access economic and

social activities without their parents’ help. For them, the lack of night and weekend transport

can be particularly frustrating. The same problem affects older users or users with

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disabilities: they might not be able to drive, and without any other mode of transport, it

means a decline in their social activities, especially as they can have health issues that limit

walking distance. For them as for unemployed people or low-incomers, there can also be an

inability to afford the cost of transport. Moreover, as we have explained it before, those on

low incomes are more likely to settle in suburbs where the lack of transportation is highly

observed, or in suburbs away from the socioeconomic center. Though, social exclusion is

emulated by the differences in accessibility for inhabitants of different neighborhoods. We

may define accessibility as the potential opportunities for interaction, measured in term of

the number of activities that can be reached in a given time or a given distance (Hansen, as

cited in Bocarejo and Oviedo, 2012). It is also linked to travel cost and to what somebody is

willing to pay to go from one place to another. From that notion, we are able to define the

causes of social exclusion: it is due to spatial, societal, political and temporal disadvantages.

An individual is excluded when he resides in a society without being able to be involved in its

activities such as education and employment, and it is easy to link this exclusion to

insufficient means to travel to the economic and social areas of a city. The use of a car can

sometime respond to the lack of a public transportation system, but it is restricted to a

certain part of the population and thus is not a good solution; in addition, it has other

disadvantages that we will discuss later on.

Then, we need to understand why a public transportation system is put in place and

how it can be funded. This means that we have to study the political concerns related to the

creation of an urban transportation system, and maybe the role of non-profit groups. Which

elements will push politicians and city governments to decide to build a new transportation

system? This kind of system is related to almost all aspects of city life, but very few cities

have had major investments in sustainable systems before a few years ago, politic decisions

preferring to fund road infrastructures. Transport policies divides, because there will always

be conflicts over how to fund and maintain a reliable transport system. Moreover “urban

transportation infrastructure and transportation behavior result from a constellation of

competing actors” (Batterbury, 2003). As said before, it requires a good planning system to

be reliable, and that means other investments. One of the difficulties lies in the different

levels of organization (national, metropolitan and local, depending on countries and cities),

creating tensions about how to fund a new project. The inequalities discussed in the two first

parts are real and result in a sense of injustice that may create new social movements.

However, social reasons may not be strong enough, and politicians need objective proofs

such as a road network stretched to capacity, expensiveness of railroads and subway, to

understand that the networks may have suffered of a lack of investment and that it is of their

responsibility to act. Non-profit groups, often environmental groups, may appear and try to

push city government to act, and partnerships between the state and those movements can

occur, especially because voters often make their decision on the basis of deception by the

politicians. Another reason for city governments to build a new transportation system is that

it may enhance development in particular areas. Stimulation of urban development can be a

major reason for the construction of the systems (Mackett and Edwards, 1997), and it can

be either part of the redevelopment of an area, for instance the city center by providing

access to its economic activities, or a mean to enhance city growth. For instance, the

Memphis and Miami metro have helped to redevelop the downtown area. The reasons why

a transportation system helps to develop an area of the city can be explained. For example,

at the beginning of suburbanization, streetcar suburbs appeared as residential areas that

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could easily be linked to the economic center thanks to the new streetcars. In the same way,

the implementation of a new railway or bus system creates an access to an area that was at

first difficult to reach, and this neighborhood will develop as people come to live or work in

the new infrastructures. Finally, the creation of the new transportation system in addition of

existing ones creates not only employment, but also attractiveness of the city and hence

stimulates the city growth.

We have seen the different challenges created by urban forms and more specifically

the social inequities resulting of insufficiency or lack of urban transportation. We also have a

sight of the political concerns related to urban transportation systems. We now may wonder

the other characteristics of an ideal system.

The question of global warming has to become essential in the considerations

toward transportation. As a matter of fact, the actual means of transport are emitting a lot of

greenhouse gases, and we need to reduce dramatically those emissions in order to preserve

the planet. But an urban transportation system also has to be well-integrated in its

environment. We are going to look for needs and proposed answers in terms of

environmentally sustainable transportation systems.

To understand why we need to worry about global warming, some explanations are

necessary. In a hundred years, the mean energy need per person has been multiplied by ten

because of urbanization, mass consumption and expansion of the service sector, while the

population has been multiplied by a thousand: the total energy need for the population is

10,000 times more than what it used to be at the beginning of the 20th century. Moreover,

the most used mean of energy production is combustion (gas, oil, coal...), which creates a

huge amount of carbon dioxide. The greenhouse effect is a natural effect but since the

industrial revolution, all the greenhouse gases that we have emitted in the atmosphere

enhance this effect and cause global warming. Dependently on the model chosen, we can

assume that in a hundred years from now the temperature will increase from three Celsius

degrees if we stay at constant emission, to six Celsius degrees if the emissions double in

fifty years (Jancovici,

2012). The

consequences aren’t

known yet but will be

different over the

planet; it will lead to the

rising of oceans,

impacts on climate

(either hotter or cooler

temperatures

depending on areas,

differences in

pluviometry and

seasons), modification

of extreme

Figure 1: Magnitude of response for CO2 emissions

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phenomenon such as hurricanes and tsunamis, impacts on human health for example with a

decrease in productivity for agriculture... Global warming has already begun and it is a non-

invertible process: what has already been emitted can’t be taken out of the atmosphere. We

can see on Figure 1 that even if we reduce our emissions to a minimum, the consequences

will still be significant. But by reducing our emissions, it will be possible to limit the increasing

of temperature and thus its consequences.

With these elements, we can understand that it is a real need for us to reduce our

emissions. Concerning transportation, it means finding ways to transport a great number of

persons emitting as little carbon dioxide as possible: the classification of vehicles should link

carbon dioxide emission to loading capacity (Olsson, 1999). Regarding this aspect, we need

to discuss the role of cars in modern cities. We know that car ownership has been growing in

cities all over the world, and people are purchasing them because is it related to a high level

of consumption, and because hypermobility is often associated with modernity. Car is a fast

and flexible mode of transport compared to most existing public urban transport modes, and

provides direct transportation to any destination. But as we have seen in the first part of this

section, cars cause environmental damages and congestion. This mode of transportation

has persisted because the main response to the rising in vehicle ownership was to expand

the road network (Batterbury, 2003), with for instance the work of Robert Moses in New

York. Congestion is a major issue of modern cities: not only it decreases the advantage of

cars in terms of rapidity and convenience, but it especially creates an environment where

living is not pleasant because it is related to a lot of nuisances such as noise, direct pollution

of the air, visible pollution, difficulties for pedestrians to move in the urban area… In a first

approach, the goal for urban planners must be to reduce dramatically the use of cars in

urban areas, but also to find alternatives with the lowest emissions possible; we will see later

on the propositions in that way. However, there can be a vicious circle in the shift between

car and public transports if it isn’t well done: if people change from car use to public

transports, the system will soon become overcrowded and service quality will be reduced,

resulting in accelerating the shift to car (Mackett and Edwards, 1997). The other problem

when speaking about switching from car to public transport is related to what we have seen

above: some areas are not enough served by the transportation system, and that can lead to

“forced car ownership” (Bannister as cited in Currie, 2009), that is to say that people do not

have over possibilities than owning a car to reach their mandatory activities. For low income

households, operating a car may represent up to 30% of their income, and we find that

households owning a car spend much more on travelling than households without cars,

though we have to recognize that their accessibility is much higher (Currie, 2009).

Replacing cars by public transportation is a necessity in terms of environment and society,

but may be particularly difficult since car use is very deeply implemented in the cities.

Finally, we may consider some propositions of systems responding to the principal

environmental matters presented above. The four main problems that humanity has to face

regarding transportation are energy, environment, security and congestion (Laurgeau, 2012).

One of the main solutions would be to use electric vehicles together with a shift to low

emissions energy production means -for example, 70% of France’s energy is nuclear

energy-, although the main problem remains that charging hours would create peaks in the

energy need. Another innovation would be to use computer controlled vehicles for buses

and cars because the vehicles would then be able to stay much closer from each other

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reduce congestion. Rail-based systems are a solution to be considered, mainly because

they respond to at least two of the four problems: a rail-based system obviously avoids

congestion if it is well scheduled, i.e. by considering that the ridership varies relatively to the

different periods of the day. The rail systems nowadays are electrical so it may be an answer

to the environmental problem. Another solution is a bus-based system, guided or unguided,

which can have the same advantages if we consider special roads for the buses and is

moreover much cheaper. As a matter of fact, “rail-based systems are more expensive than

bus-based systems to construct, and the operating costs are higher” (Mackett and

Edwards, 1997). But such systems often appear as more attractive, and politicians that

want to please their electors tend to orientate the planners to choose the construction of a

tramway more than the implementation of a bus rapid transit system (BRT), although the

BRT fulfills most of the requirements since it also is able to transport high passenger

volume. In another way, an innovative solution concerns the creation of an on-demand

transportation system to decrease the cost of rail systems. To do so, the solution is to

decrease the size of the vehicles, permitting the use as an on-demand system. The idea is

to provide inhabitants of a city a public mean of transport with some of the advantages of the

privates means such as automobiles and taxis with

a relatively low cost, because the weight of the

vehicle will be much lower (Dearien and Plum,

1993). CYBERTRAN is a system which has been

tested, with a carriage of six to thirteen passengers

and vehicles travelling on a guideway. The ideal for

this mode of transport is an individual seat instantly

available, but practical limits require multiple

occupancy so we need to find the optimum size of

the vehicle: the passenger capacity decreases with

the increasing of the number of vehicles, which is

limited. Another advantage of an on-demand system

is in term of energy savings. As a matter of fact, a

scheduled public transportation mean will leave

even if it is empty and is moreover bigger than those of this system, which can put in service

only the number of small vehicles required at the moment.

The concerns about global warming have made us wonder about the use of the car

in modern cities. We have seen why it is so widely used, but also its main drawbacks in term

of environmental sustainability and we understand that we have to find alternatives to this

way of transportation; moreover some environmentally sustainable systems have been

presented.

With all the elements explained in the two firsts parts, we are now able to

understand the principle of social sustainability and its correlation with urban transportation.

We are also aware of the necessity to have more environmentally sustainable systems, by

reducing the use of car as a start. We may then wonder what systems already exist over the

world, and try to understand the methods that we need to put in place for the choice of new

projects.

Figure 2: System cost versus Vehicle capacity

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We have to consider what already exists or at least is planned over the world before

looking for ways to improve a transport system. As we are living in Ottawa, let’s start with

this city. The public transit service is operated by OC Transpo and is constituted of a bus

rapid transit network and a light rail transit on one line. The bus rapid transit system (BRT) is

quite successful as the main routes avoid most of the traffic using bus roads, overpasses

and trench highways; those bus roads are called Transitway. Other lines might partially use

the Transitway. The principal cause for service delay is congestion in the downtown section

of the network on Slater Street, because buses have to use the same road as private

vehicles. The buses are accessible to disabled persons with their low floor and the fleet is

mostly high-capacity buses. The buses use diesel but there is a Green Initiative aiming to

reduce greenhouse gas emission by examining the cost of bio-diesel and especially

implementing 177 diesel-electric hybrid buses for the routes with frequent stops. The Light

rail transit (O-Train) operates since 2001 and is also a success since it exceeds its ridership

forecast. The construction cost was rather low since it used a former railway running north-

south, and the line was to be replaced and extend (since it was only a pilot project) to reach

the downtown core. There, it would have used the lanes that are now part of the Transitway

and would have helped to reduce the number of buses in the downtown area. The project

has been cancelled because of its cost but another project is to open an extended line by

2018. Critics than can be done about the global OC Transpo network are that we can

observe capacity problems for east-west transportation (hence the new O-train project) and

that money may not be well spend since the O-train accommodates less people than the

Transitway and is more expensive, but the system is rather sustainable in both aspects of

the subject. Over the world, as study has been done over 46 urban public transport systems

satisfying the same criteria: it is the UTOPIA project (Mackett and Edwards, 1997). The

studied systems are either light rail or bus systems, some are operating and others are

planned. The results show the impact of new transportation systems and how it is related to

the decisions that have been made during the planning of the project. The new urban

transports are usually aiming to provide better access for all inhabitants of the city, increase

total transport capacity, provide access to jobs from low employment areas and reduce

traffic congestion, but also improve the environment for the most recent projects. Another

reason is stimulating urban development. With these objectives, the most direct impacts

observed is an increased ridership and decrease in congestion.

Before considering the methods used to choose between different possibilities for a

new transportation system, we have to understand the funding strategies, and especially

those regarding operating costs, because the global funding of such projects depends too

much on countries and systems to be studied here. An ideal project seeks to cover entirely

transport operating costs by fare revenues, but we have to look for a socially sustainable

option for operating costs. As a matter of fact, a too high fare represents a limitation of the

use of the system. Gleeson and Randolph (as cited in Currie, 2009) explain to us the

concept of transport poverty: “Transport poverty occurs when a household is forced to

consume more travel costs than it can reasonably afford”. If the operating cost of the system

is too high, the government might have to put in place funding strategies to support transport

fares for particular social groups, for example students, and in that way avoid to a maximum

transport poverty. The study of accessibility as we explain it in the third part of this section

leads to consider a differentiated fare system (Bocarejo and Oviedo, 2012). A cross

subsidy fare system seeks to define a fare according to the income of each socioeconomic

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level. In Bogota, it has been proposed to reduce of 23% the fare for low-incomers, increase

it of 14% for high-incomers, and keep it unchanged for the middle income class, taking into

account the purchasing power and the demand of those classes. It has been done together

with parceling out the city in zones according to their accessibility. The percentage of income

used on transport related to the accessibility of two neighborhoods of Bogota is presented in

Figure 3. Chico Lago is a rich neighborhood with an average travel time of 36 minutes for its

inhabitants to reach their mandatory activities, whereas Lucero is a poor neighborhood with

an average travel time of one hour. The percentage of income used on transport is much

more lowed in Lucero than it is increased for Chico Lago after the application of the cross

subsidy policy. It means that this policy could actually reduce access inequities to

opportunities in the city. A last funding plan for operating costs that can be proposed is the

example of London: the mayor instituted an eight dollars fee for vehicles wishing to enter

inner London, which is a form of ecotaxation, and then increased bus service (Batterbury,

2003).

To implement those new urban public transports, governments and city planners

need consistent methods to choose between the numerous possibilities, and some

mathematical models have been developed. For example, the multi-criteria approach that

has been used to select an option of environmentally sustainable system in Delhi (Yedla

and Shrestha, 2003) proposes to rank the options by considering different criteria both

qualitative and quantitative and not only quantitative ones as we are used to do. The

quantitative criteria used are energy, environment and cost while the qualitative ones are

technology availability, adaptability and barriers to implementation, and the ranking is done

with analytic hierarchy process. We consider different options regarding replacements that

can be done in three transportation systems, for instance converting conventional fuel

cars/buses into compressed natural gas cars/buses, and consider the importance of the

criteria regarding different groups of actors such as experts and users. For quantitative

criteria, a potential is calculated while surveys have been used among the groups for the

qualitative ones. Figure 4 shows the differences between priorities in terms of quantitative

criteria and priorities calculated by considering the qualitative criteria (IQQC designs

integrated quantitative and qualitative criteria), and it proves the need to broaden the criteria,

otherwise the solution adopted may not be adapted to the real needs of the population.

Figure 3: Benefits of a cross subsidy policy

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Another method that can be used

concerns the computation of

accessibility as “an indicator of the

effort required for not being excluded”

(Bocarejo and Oviedo, 2012), which

is often neglected in the study of a

new system. We can estimate

numerically the availability of

opportunities generated by

transportation. It is a function of the

accessibility of the origin zone, the

attractiveness of the destiny zone,

the distance between the two zones in terms of travel time, and travel cost related to

individual incomes. The article of Bocarejo and Oviedo (2012) presents the results

obtained for the city of Bogota. Finally, we have to deal with the gap between expectations

and reality. In most observes systems for the UTOPIA project (Mackett and Edwards,

1997), the actual ridership was well lower than the forecasted one while the capital costs

was over 50% higher than predicted. Most of a new ridership is expected to come from a

transfer from a former mode of transport to the new one. We also have to keep in mind that

even a successful system might lose passengers over time as decentralization occurs. The

differences between expectations and reality are related to political, analytical and financial

factors. The political factor lies in the fact that planners are under pressure from politicians,

and investments depends on politics: financial concerns may not take social concerns into

account. Moreover, the logic that starts a new project may not be rational, for example if it

follows a tendency. About the analytical factor, we can say that planners may not be aware

that most cities developed themselves relying on existing transportation systems (we find

again the example of streetcar suburbs) and so any new system will have a much lower

impact than the original ones.

The examples of Ottawa together with other examples of urban systems all over the

world through the UTOPIA project permitted us to understand better the current stakes in

term of public transportation. We now have concrete ideas on how to reduce social

inequities and choose a new transportation system considering as many elements as

possible.

In conclusion, we can assert that modern cities create new forms of

challenges. Those challenges are either social, with the apparition of neighborhoods with

different developments and social inequalities, or environmental because of the global

warming worsened by the increasing of population and mass consumption. We have seen

that a public transportation system plays a huge part regarding those two issues; the

concept of accessibility as potential to reach our mandatory activities enhances the fact that

those systems create inequities and social exclusion, and we also know that they can help to

reduce a lot our emissions in carbon dioxide by avoiding as much as possible car use and

congestion and developing environmentally sustainable public vehicles. But the purpose of

this paper was also to present some concrete solutions to develop environmentally and

socially sustainable means of transport, that is to say to understand how we can create a

Figure 4: Priorities set to different alternatives in different approaches to decision making

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system which tends to reduce social exclusion, respond to the inhabitants expectations and

reduce the environmental impact of transports in cities. It goes through the consideration of

operating cost funding and methods to choose the most accurate system that we want to put

in place in a city. We reach the conclusion that the systems that have been used until now

for urban transportation often forgot to consider social needs and environmental issues, but

that the new researches about social impacts of transportation give us new elements to

improve urban public transports. The research could be expanded considering the

advantages of a multi-modal transportation system.

Figure table

Figure 1, p. 4: Magnitude of response for CO2 emissions taken from Jancovici (2012)

Figure 2, p. 6: System cost versus Vehicle capacity taken from Dearian and Plum (1993)

Figure 3, p. 8: Benefits of a cross subsidy policy taken from Bocarejo and Ricardo (2012)

Figure 4, p. 9: Priorities set to different alternatives in different approaches to decision

making taken from Yedla and Shrestha (2003)

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References

Academic references

Currie, G. (2009). Australian Urban Transport and Social Disadvantage. The Australian

Economic Review, vol. 42, no. 2, pp. 201–8.

Batterbury, S. (2003). Environmental Activism and Social Networks: Campaigning for Bicycles and Alternative Transport in West London. ANNALS, AAPSS, p590. Yedla, S., Shrestha, R. M. (2003). Multi-criteria approach for the selection of alternative options for environmentally sustainable transport system in Delhi. Energy Program, School of Environment, Resources and Development, Asian Institute of Technology, Transportation Research Part A37, pp. 717–729. Olsson, L. (1999). Steps towards an environmentally sustainable transport system. The Science of the Total Environment, 235, pp. 407-409. Dearien, J. A., Plum, M. M. (1993). The Capital, Energy, and Time Economics Of An Automated, On-Demand Transportation System. IEEE AES Systems Magazine, pp. 28-32. Mackett, R. L., Edwards, M. (1997). The impact of new urban public transport systems: will the expectations be met ? Transpn Res.-A, Vol. 32, No. 4, pp. 231-245. Bocarejo, J.P., Oviedo, D. R. (2012). Transport accessibility and social inequities: a tool for identification of mobility needs and evaluation of transport investments. Journal of Transport Geography 24, pp 142–154. Zheng, X, Fu, X. (n.d.). Reflections on Legislation about Construction of Integrated Transportation System. IET, The Fifth Advanced Forum on Transportation of China.

Other references

Jancovici, J.M. (2012). Course Energie et Changement Climatique, classes 1-3. Mines

ParisTech.

Laurgeau, C. (2012). Conference about mobility and new technologies in information and

communication, November 30, 2012. Mines ParisTech.

Chen, X., Orum, A. M., Paulsen, K. E. (2013). Introduction to cities – how place and space

shape human experience. Blackwell Publishing Ltd.

Informations about OC Transpo :

http://en.wikipedia.org/wiki/Ottawa_Rapid_Transit

http://www.octranspo1.com/about-octranspo