Transport and Sustainability

Authors: Dr. Jean-Paul Rodrigue and Dr. Claude Comtois

1. Sustainable Development

An issue that has triggered concerns over the recent decades relates to the capacity of the global economy to accommodate an enduring demographic, economic and resource consumption growth. Since the 1970s, many statements have been made asserting that the world would be unable to sustain such growth without a possible socioeconomic and/or environmental breakdown. While these perspectives have been demonstrated to be inaccurate, since resources availability and the quality of life increased, there are enduring concerns that at some point a threshold will be reached. These concerns were well underlined by the Brundtland Commission in 1987 which defined sustainable development as

"Development which meets the needs of the present without compromising the ability of future generations to meet their own needs".

As the above quote suggests, sustainable development is a vague concept that is subject to numerous interpretations of what are present needs and what would be the needs of future generations. Should it be based on a minimal standard of living threshold or let to what standard of living each individual is able to afford based upon current price and availability? It is not surprising that the subject is prone to much demagogy leading to confusion in terms of its nature, consequences and appropriate response. It is however generally agreed that a sustainable society favors conditions that benefits the environment, the economy and the society without compromising the welfare of future generations. The problems remains how to define and assess the welfare of future generations, which is essentially impossible. Still, as history clearly demonstrates, the conditions of future societies will largely depend upon the legacy of current societies on resources and the environment. All form of assets (capital, real estate, infrastructures, resources) passed on to the next generation should be at least of equal value (utility) per capita. The basic definition of sustainability has been expanded to include three major points (often referred as the three Es):

Social equity. Relates to conditions favoring a distribution of resources among the current generation based upon comparative levels of productivity. This implies that individuals or institutions are free to pursue the ventures of their choice and reaps the rewards for the risk they take and the efforts they make. Social equity should not be confused with welfare programs (socialism) where the productive segment of the population agrees or is coerced to support a non productive segment; this is not equity but redistribution. Thus, central planning and socialism are much at odd with the concept of social equity.
Economic efficiency. Concerns conditions permitting higher levels of economic efficiency in terms of resource and labor usage. It focuses on competitiveness, flexibility in production and providing goods and services that supply a market demand. Under such circumstances, factors of production should be freely allocated and markets open to trade.
Environmental responsibility. Involves a "footprint" which is lesser than the capacity of the environment to accommodate. This includes the supply of resources (food, water, energy, etc.), but also the safe disposal of numerous forms of wastes. Its core tenets include the conservation and reuse of resources.

Another important debate relates to what extent public entities (both at the national and supra-national levels) have a role to play. More bluntly, should sustainability be coerced by governments or be the outcome of market forces? Environmentalists are dominantly leaning towards coercion as they distrust market forces and would argue that sustainability is a much too long term concept to be addressed by corporations focused on the short term. A counter argument could be made that the time horizon of governments, especially democratic regimes, is also very short and on rare instances governments have shown to be proactive regarding environmental matters. The question remains as if expectations can be placed on entities that seek to optimize positive perception (governments) or on entities that seek to optimize efficiency (corporations). Paradoxically, while governments tend to be inflexible and unable to adapt, corporations have demonstrated a resounding ability to shift their strategies and provide products that reflect the needs of their customers (including environmentally responsible products). It could thus be argued that the private sector is more likely to achieve sustainability than the public sector.

Societies do not contribute to environmental problems at the same level. A comparison between developed countries and developing countries reveals that the developed world consumes 70% of the world’s energy, 75% of minerals and 85% of wood. For example, the Sears Tower in Chicago consumes more energy than an American city of 150,000 or an Indian city of 1 million. Sustainability can be thus expressed at two spatial levels:

Global. Long term stability of the earth’s environment and availability of resources to support human activities.
Local. Localized forms often related to urban areas in terms of jobs, housing and environmental pollution.

Since a growing share of the global population is urbanized, sustainability has increasingly become focused on urban areas. Major cities are requiring a vast array of supporting infrastructures including energy, water, sewers and transport. A key to urban sustainability issues is linked with the provision and maintenance of a wide range of urban infrastructure. Every city has specific infrastructure and environmental problems. For instance, cities in developing countries have chronic deficiencies in the provision of the most basic infrastructure while their environmental conditions are deteriorating.

Infrastructures can be publicly or privately owned. Public infrastructures have the advantage to be available to a larger share of the population at a low cost, but are expensive for the government to maintain (subsidies). Private infrastructures tend to service a smaller share of the population, at the choice of the infrastructure company, but are financially profitable. As income levels increase, some infrastructure problems are solved while some environmental problems are created. For instance, an increase in income is linked to better sanitation and water provision, but at the expense of greater waste and carbon dioxide emissions.

2. Transportation and Sustainability

Transportation, as a core component supporting the interactions and the development of socioeconomic systems, has also been the object of much consideration about to what extent it is sustainable. Building upon the Brundtland Commission sustainable transportation can be defined as:

"The ability to meet today’s transportation needs without compromising the ability of future generations to meet their transportation needs." (Black, 2010)

Again, this is a vague statement that has several parameters difficult if not impossible to assess, particularly of what could be the transportation needs of future generations. Most studies agree that automobile dependence is related to an unsustainable urban environment. However, such an observation is at odd with the mobility choice and preferences of the global population where the automobile is rapidly adopted when income levels reach a certain threshold. Other transport alternatives commonly do not measure up to the convenience of the automobile. Private and flexible forms of transportation, such as the automobile, are thus fundamental to urban mobility and should not be discarded as options for the sake of sustainability. A bias is observed in the transport community towards an emphasis for public transit and non-motorized transportation as the dominant, if not sole, strategy towards sustainable transportation. Yet, almost all public transit systems are financially unsustainable, imposing burdens on the society. Freight transportation must also been considered in this process considering the substantial growth of raw materials and goods being traded in a global economy. In fact, freight transportation relies on much more environmentally sound modes such as rail and maritime transport.

Despite the apparent and projected success of measures to promote transport sustainability, they have their limits. The formation of compact and accessible cities must be allowed to contend with the already existing built environment while considering several limits to development and urban renewal through temporal constraints and common limitations in capital availability. Indeed, the built environment cannot change quickly enough to solve the bulk of problems related to unsustainable transport. Most of the investment that is already in place will remain in place for 50 years or more and new investment (in additional or improved infrastructure) will not represent much more than a few percentage points change in terms of reducing traffic congestion and ease of access to strategic urban locations. It is necessary, therefore, to favor conditions that would influence modal choice, the supply of transport services and attractiveness of walking and cycling within the constraints of the built environment. While policies, rules and regulations have a tendency to favor a misallocation of resources (such as compliance), users tend to instinctively react to price signals and discard modes that are becoming costly (unsustainable).

Transportation and sustainability for both passengers and freight must also also contend with mitigation versus adaptation issues:

Mitigation concerns the improvement of productivity and efficiency of existing modes, terminals and managerial approaches so that environmental externalities are reduced. They tend to be short to medium term strategies.
Adaptation is a change in the level of use and the market share of respective modes to better reflect a long term trend, such as higher energy prices and stricter environmental regulations.

In any cases, the challenges of sustainability lean on coping with changes in transport demand while improving transport supply.

3. Coping with Transport Demand

In order to effectively reduce the adverse impacts of current transportation systems, existing transportation / land use development patterns must adapt. A higher level of integration between transportation and land use often results in increasing levels of accessibility without necessarily increasing the need for automobile travel. There are several ways in which transportation systems can adapt to cope with transport demand and reach a better level of sustainability:

The densification of urban landscapes where high densities encourage the use of public transport and pedestrian or bicycle travel as cost-effective alternatives. This can involve mixed and compact land use patterns are clustered together and can result in reduced automobile trips and increase some of the sustainable transport alternatives. This densification should be the outcome of developers realizing that investing in denser spatial structures concomitantly reduce costs and increase profits. With strong market signals, land economics often dictates more efficient and higher density uses.
Pricing strategies that remove artificial signals such as subsidies and let the users assume the real cost of transportation. Once the pricing of transportation is sent as a clearer signals to users, they are likely to adapt their usage in accordance to their capacity to afford them. If unsubsidized transportation is inexpensive (of that its price is declining), it is a good signal of its sustainability. Increasing transport costs, and the pressure to subsidized them to keep them are a signal that they may be unsustainable.

The implementation of such strategies rely heavily on the existing spatial structure and the distribution of its land use and transport networks. It is therefore crucial for such density to be combined with transport alternatives that will enable the reduction of traffic congestion and environmental damage. Hence, an integrated strategy for sustainable urban transport requires a better understanding of the relationships between the transportation and land use sectors across an entire metropolitan area.

Some of the most easily implemented policies to help reduce urban travel demand include full-cost pricing and traffic bans. Each of these strategies will produce variable results depending on the urban context in which they are implemented:

Full-cost pricing involves the full (or partial) recovery of costs related to the public investments incurred by varying levels of government in relation to constructing, repairing and operating road networks. It includes road pricing, pollution taxes and fees, and parking controls. Motorists are charged a floating fee (depending on the variability of demand in peak and off peak hours) for using targeted roads. Can be implemented through a variety of techniques such as tolls, or licensing fees. The main objective of this strategy would be to discourage automobile use during peak periods and to promote the use of alternatives modes of transport.
Taxes and pollution fees are other methods of recovering transportation costs while attempting to reduce heavy traffic loads. They would involve the implementation of increased taxes on vehicle and fuel purchasing as well as imposing fees on vehicle owners who operate at low levels of energy efficiency. However, taxes are a form of coercion and the question remains about how their proceeds are allocated.

In addition to reducing traffic congestion, such strategies are perceived to be beneficial to the elevated concerns of air pollution. However, since they are fee-based they are very unlikely to be successfully implemented in developing countries. The following strategies are more constraint-based than fee-based:

Parking controls, either in raising parking prices or reducing the amount of parking areas, can be used to deter the use of privately owned vehicles in areas of highest demand by raising the price of commuting to high density areas. Again, the expected result of this strategy is to encourage (or force) commuters to seek cheaper alternatives either in mass transit or carpooling.
The strategy of traffic bans is a more direct method of reducing traffic demand. Through traffic bans (in the form of license number restrictions), the responsible regional or municipal institutions would exert direct control over the allowable limit of vehicles in a given urban area depending on measures of transport supply-demand functions or arbitrary estimates of carrying capacity. This strategy is however rife with the possibility of corruption since governmental agencies would be responsible to dictate the number and the allocation of permits.

Such coercive strategies would thereby impose a limit on the number of vehicles in circulation and, correspondingly, reduce congestion and air pollution while promoting the use of alternative means of transport. Their fundamental shortfall is they assume that government entities actually know solutions to urban transport problems (such as the appropriate number of parking space), which is rarely the case.

4. Improving Transport Supply

While the implementation of demand oriented policies and mechanisms is an important component in promoting sustainable transport, it is pivotal that these measures be coupled with equally efficient transport supply improvements, including improving vehicle propulsion technologies. Transportation infrastructure should be expanded to accommodate rapidly growing transport demands in conjunction with growing extended metropolitan regions. As long as the global urban population continues to grow, particularly in developing countries, there pressures to expand urban transport infrastructures. The challenges are to expand and improve the transportation supply in such a way that the automobile is only part of the equation rather than the focus. Hence, in order to implement effective transport supply expansion policies, fast, efficient, reliable, and accessible transport alternatives must be provided, preferably through private initiatives.

This can be achieved by expanding public transit infrastructure, by improving existing public transit services, and by making cities friendly to pedestrians and non-motorized vehicles. The issue of sustainability is giving public transit a new impetus since the bulk of its prior rationale was to mitigate automobile dependency and provide equity in mobility. This is however an extremely difficult challenge considering the prominence that the automobile is achieving worldwide. It must be acknowledged that this prominence is the outcome of many positive factors favoring the automobile such as flexibility, convenience and relatively low costs. Automobile dependency is thus the outcome of market forces expressed as consumer preferences. Combating this trend would thus be foolhardy in spite of all what planners or policymakers may assert. Thus, alternatives can be provided if they prove to be cost effective while fulfilling a niche demand. They may include:

Reconciling public and private transport. Both forms of transportation have roles to fulfill. The long term trend has been a substantial growth of private transport in spite of all the efforts made to promote public transportation. In the North American context, this has roughly been a failure. Therefore, public transportation being the least flexible of both forms of transport, should assert a complementary role. The expansion and development of mass transit systems which must not only satisfy a niche demand but also make effective use of urban space by conforming to a number of factors including urban form, density, and modal preferences. In doing so, the fleets and networks must ensure a level of flexibility while ensuring low ridership costs which would reduce per-passenger pollution levels and traffic congestion alike. Comparatively, methods of improving and upgrading existing public transit services should include the improvement of service coverage and quality as well as increasing frequency where and when it is most needed (during peak hours). Also, the chosen modes of mass transit transportation – whether bus, light rail, subway, trams, "group" taxis, or a combination of two or more – should be designed, implemented, and operated in a way that will facilitate and predicate complementarity and interchangeability while remaining cost-effective. Most of the time, such goals are simply wishful thinking.
One of the most important and most often overlooked element in improving urban transport systems is the ability to provide safe and ample access to non-motorized transport modes to the urban population. The integration of individual modes of non-motorized transport such as walking and cycling, if properly promoted and encouraged, can provide access to shopping, schools, and work for a growing proportion of the population. Also, for cities struggling with serious traffic congestion and air pollution, non-motorized transport should be considered as an indispensable and beneficial alternative to private vehicles while serving as a crucial link in an integrated public transportation system. While cycling can be a challenging mode to promote and integrate in the urban transport fabric (e.g. taxing weather conditions such as winter or excessive heat), there is a clear and unmet need to better integrate pedestrian movements into sound urban design and architecture.

Subsequently, where urban transport priorities are manifested and dictated by poverty, traffic congestion, and pollution from motor vehicle emissions, efforts to improve the transportation supply should emphasize the need to reduce the externalities of motorized transport through the expansion and improvement of mass transit and, most of all, encourage the proliferation of non-motorized means of urban transport. Such a goal is however in contrast with the modal choice reality of many cities, particularly those experiencing rapid growth. The issue of sustainable transport thus remains elusive.