Toxic air pollutants are associated with cancer, cardiovascular, respiratory, and neurological diseases. Carbon monoxide CO , when inhaled, reduces the availability of oxygen in the circulatory system and can be extremely harmful and even deadly at specific concentrations.
Nitrogen dioxide NO2 emissions from transportation sources reduce lung function, affect the respiratory immune defense system, and increases the risk of respiratory problems. The emissions of sulfur dioxide SO2 and nitrogen oxides NOx in the atmosphere form various acidic compounds that, when mixed in cloud water, creates acid rain. Acid precipitation has detrimental effects on the built environment, reduces agricultural crop yields, and causes forest decline. Smog is a mixture of solid and liquid fog and smoke particles formed through the accumulation of carbon monoxide, ozone, hydrocarbons, volatile organic compounds, nitrogen oxides, sulfur oxide, water, particulates, and other chemical pollutants.
The reduction of visibility caused by smog has several adverse impacts on the quality of life and the attractiveness of tourist sites. Particulate emissions in the form of dust emanating from vehicle exhaust and non-exhaust sources such as vehicle and road abrasion impact air quality. The physical and chemical properties of particulates are associated with health risks such as respiratory problems, skin irritations, eyes inflammations, blood clotting, and various types of allergies.
Smog is often exacerbated by local physical and meteorological conditions, creating periods of high smog concentration and public responses to mitigate them, such as restricting automobile use temporarily. Air quality issues have been comprehensively addressed in advanced economies, with substantial declines in the emissions of a wide range of pollutants. In developing economies, rapid motorization has shifted the concern to the large cities of China and India among those the most impacted by the deterioration of air quality.
Noise represents the general effect of irregular and chaotic sounds on people as well as animal life. Basically, noise is an undesirable sound. The acoustic measure of the intensity of noise is expressed in decibel dB with a scale ranging from 1 dB to dB.
Long term exposure to noise levels above 75 decibels severely hampers hearing and affects human physical and psychological well-being. Noise emanating from the movement of transport vehicles and the operations of ports, airports, and railyards affects human health through an increase in the risk of cardiovascular diseases.
Ambient noise is a frequent result of road transportation in urban areas, which is the cumulative outcome of all the noise generated by vehicles ranging from 45 to 65 dB , impairs the quality of life and property values.
Falling land values nearby acute noise sources such as airports are often noted since buyers are less willing to bid on properties in areas of elevated noise levels. Many noise regulations impose mitigation if noise reaches a defined level, such as sound walls and other soundproofing techniques. Transport activities have an impact on hydrological conditions and water quality. Fuel, chemicals, and other hazardous particulates discarded from aircraft, cars, trucks, and trains or port and airport terminal operations can contaminate hydrographic systems.
Because demand for maritime shipping has increased, marine transport emissions represent the most important segment of water quality impact of the transportation sector. The main effects of marine transport operations on water quality predominantly arise from dredging, waste, ballast waters, and oil spills. Dredging is the process of deepening harbor channels by removing sediments from the bed of a body of water. Dredging is essential to create and maintain sufficient water depth for shipping operations and port accessibility.
Dredging activities have a two-fold negative impact on the marine environment. They modify the hydrology by creating turbidity that can affect marine biological diversity. The contaminated sediments and water raised by dredging require spoil disposal sites and decontamination techniques. Waste generated by the operations of vessels at sea or at ports causes environmental problems since they can contain a very high level of bacteria that can be hazardous for public health as well as marine ecosystems when discharged in waters.
Besides, various types of garbage containing metals and plastic are not easily biodegradable. They can persist on the sea surface for long periods of time and can be a severe impediment to maritime navigation in inland waterways and at sea and affecting as well as berthing operations.
Ballast waters acquired in a region may contain invasive aquatic species that, when discharged in another region may thrive in a new marine environment and disrupt the natural marine ecosystem. Invasive species have resulted in significant changes in nearshore ecosystems, especially in coastal lagoons and inlets. Major oil spills from oil cargo vessel accidents are one of the most severe problems of pollution from maritime transport activities.
The environmental impact of transportation on soil quality particularly concerns soil erosion and soil contamination. Coastal transport facilities such as ports have significant impacts on soil erosion. Shipping activities are modifying the scale and scope of wave actions leading to damage in confined channels such as river banks. Highway construction or lessening surface grades for port and airport developments have led to an important loss of fertile land. Soil contamination can occur through the use of toxic materials by the transport industry.
Fuel and oil spills from motor vehicles are washed on roadsides and enter the soil. Chemicals used for the preservation of wooden railroad ties may enter the soil. Hazardous materials and heavy metals have been found in areas contiguous to railroads, ports, and airports. Transportation also influences biodiversity. The need for construction materials and the development of land-based transportation has led to deforestation. Many transport routes have required draining land, thus reducing wetland areas and driving-out water plant species.
The need to maintain road and rail right-of-way or to stabilize slope along transport facilities has resulted in restricting the growth of certain plants or has produced changes in plants with the introduction of new species. Many animal species are becoming endangered as a result of changes in their natural habitats and reduction of ranges due to the fragmentation of their habitat by transportation infrastructures.
Transportation facilities have an impact on the urban landscape. The development of port and airport infrastructure is a significant feature of the urban and peri-urban built environment.
Social and economic cohesion can be severed when new transport facilities such as elevated train and highway structures cut across an existing urban community. Arteries or transport terminals can define urban borders and produce segregation.
Major transport facilities can affect the quality of urban life by creating physical barriers, increasing noise levels, generating odors, reducing urban aesthetic,s and affecting the built heritage. The expansion of logistics activities has also been an indirect factor of land take in suburban and periurban areas. Externalities are an economic concept that refers to the activities of a group that has consequences , positive or negative, intended or unintended, on other groups.
These consequences, particularly if they are negative, are not fully assumed by those causing them. Therefore, the impacts are externalized. A common example of a positive externality concerns technology since it obviously benefits the innovative firm but also the whole economy through various productivity improvements or improved convenience.
Negative externalities are highly relevant over environmental issues since many of the negative consequences of pollution are assumed by the whole society. The environmental externalities of transportation include the consideration of physical measures of environmental damage and the evaluation of involved costs for society.
The main fallacy underlined by externalities is that the costs attributed to a few sources e. Knowing the sources of environmental externalities is a relatively easy undertaking. At the same time, the evaluation of damage and other costs has not yet reached comparative standards among governmental and non-governmental agencies.
The challenge resides over three issues:. The costs of environmental externalities can be considered from economic , social, and environmental dimensions. The basic types of transportation externalities attributed to the environment fall within air pollution, water pollution, noise, and hazardous materials.
Establishing and quantifying environmental externalities is a complex undertaking. Quantification is at its preliminary stage, and many have used this argument to differ the application of several environmental policies by lobbying governments.
For instance, in the s it took time to accumulate enough evidence to demonstrate the impacts of sulfur emissions, mainly originating from coal power plants, on rain acidification, and implement mitigation strategies scrubbers, shift to natural gas. In the s the impacts of chlorofluorocarbons and hydrochlorofluorocarbons on atmospheric ozone led to a series of regulations e.
Montreal Protocol of banning their use in the manufacturing of aerosols and refrigerants. Additionally, the wider the geographical scale, the more complex the environmental problem becomes since it involves cross-jurisdictional issues.
Recent attempts to reach a consensus about climate change, such as the Paris Agreement of , have underlined the complexity of multilateral environmental agreements over a complex issue that cannot be effectively quantified.
Parties simply make general non-binding commitments. This has several implications. First, when specific sources are concerned, like road transportation, users only take account of the direct costs of modal ownership like a car vehicle, fuel, insurance, etc. Ownership is often the only entry and utilization cost for several transportation modes. Society generally assumes the role of providing and maintaining infrastructure and other indirect costs like damage to structures and infrastructure, losses in productivity, cleanup, health services, and damage to ecosystems.
Second, the geographic separation between sources and recipients is often acute. Acid rains and climate change are prominent examples.
On a local level, a community may be affected by noise levels well over its contribution notably near major highways , while another e. There is a tendency towards a shift from direct to indirect consequences for environmental externalities , as of total costs involved.
For instance, the absolute levels of air pollutant emissions have considerably dropped in developed economies. The problem of source reduction by vehicles was addressed because it was a straightforward cause of air pollutant emissions.
This has tended to displace problems elsewhere and developed new types of externalities. Thus, the relative share of air pollution impacts is lessening, but not the number of vehicles, investment in infrastructure, or noise levels, which have their own externalities. Reductions in the relative importance of one type of externality redirect the focus on other types that were less addressed, but probably as important in the overall impacts of transport over the environment.
Transfers and additions of costs are prevalent attributes of environmental externalities. Trying to lessen economic costs will either lessen or worsen social and environmental costs, depending on the externality. In the context of limited resources, the distribution of economic, social, and environmental costs takes an important role as to what type of damage is acceptable and in what proportions. It is clear from past strategies that several economic costs have been minimized, notably for producers and users, while social and environmental consequences were disregarded.
This practice no longer applicable since the society is less willing to bear the costs and consequences of externalities for various reasons public awareness, quality of life considerations, high health costs, etc. Air pollution is the most important source of environmental externalities for transportation , mainly because the atmosphere enables a fast and widespread diffusion of pollutants.
Although the nature of air pollutants is clearly identified, the scale and scope of how they influence the biosphere are subject to controversy. On the positive side, emissions of the most harmful air pollutants, such as Carbon Monoxide and Volatile Organic Compounds, have declined despite substantial growth in the number of vehicles, which is indicative of the increasing levels of environmental compliance of vehicles.
Carbon Dioxide emissions have increased proportionally with the growth of transportation usage. As all externalities, costs are very difficult to evaluate because several consequences are not understood, the problems could be at another scale or highly correlated with others, and value monetary or other cannot be conclusively attributed.
Two major groups of factors are contributing to air pollution, notably in urban areas. From a general perspective, the costs of air pollution associated with transportation can be grouped within economic , social, and environmental costs.
Externalities related to water pollution are almost all indirect consequences. It is thus difficult to evaluate and to appraise the specific contribution of transportation over various environmental issues, which explains that problems tend to be addressed on a modal basis.
Noise emissions can be represented as point a vehicle , line a highway and surface ambient noise generated by a set of streets sources. Noise pollution is only present as vibrations. For instance, for a road vehicle, vibrations are created through the internal combustion engine, moving parts transmission , and friction on the surface over which a transport mode operates. The impacts of noise are strictly local, as vibrations are quickly attenuated by the distance and the nature of the landscape trees, hills, etc.
A hazardous material is a substance capable of posing an unreasonable risk to health, safety, and property when transported in commerce. Considering the large amounts of freight being shipped through transport systems, hazardous materials have become a concern. Several hazardous materials hazmat releases are spectacular events, notably when it involves a supertanker or a train convoy. However, we must consider that maritime transportation only accounts for 0.
Other transportation modes are thus important sources of hazmat release in the environment, even if they mostly involve small quantities. Minimal information is available on the nature and consequences of hazmats released during transportation, except for safety regulations.
The effects of hazmat release are always punctual but intense. The nature of the effect is related to the type of accident and the hazmat involved. It can range from a small-scale accident where limited quantities of hazmat are spilled, to notable accidents requiring prompt intervention and evacuation of local residents.
Thus, transportation has a wide array of environmental externalities , some of which can be reasonably assessed while others are mostly speculative, but often taken as facts by environmentalist groups. Externalities are also occurring at different geographical scales , and some may even overlap over several scales. The bottom line is that better transport practices, such as fuel-efficient vehicles, that reduce environmental externalities are likely to have positive economic, social, and environmental consequences.
While the public sector is incited the address the environmental impacts of transportation through policies and regulations, the private sector deals with compliance and tries to innovate. This iterative process is complex, but the environmental aspects of transportation have been addressed more comprehensively. It remains to be seen about which strategy is the most beneficial as in all environmental matters much subjectivity and often ideology prevails.
Skip to content Author: Dr. Jean-Paul Rodrigue Transportation systems, from infrastructures to vehicle operations, have environmental impacts ranging from noise, the emission of pollutants to climate change. The Issue of Transport and the Environment The issue of transportation and the environment is paradoxical since transportation conveys substantial socioeconomic benefits, but at the same time, transportation is impacting environmental systems.
These impacts fall within three categories: Direct impacts. The immediate consequence of transport activities on the environment where the cause and effect relationship are generally clear and well understood.
For instance, noise and carbon monoxide emissions are known to have direct harmful effects. Indirect impacts. The secondary or tertiary effects of transport activities on environmental systems. They are often of a higher consequence than direct impacts, but the involved relationships are often misunderstood and more challenging to establish. An integrated approach is presented for systematically incorporating social, economic, and environmental factors into transportation planning and decision making.
The timely identification is stressed of the nature, magnitude, and incidence of these potential factors so that in all phases of transportation planning, alternatives may be developed that avoid or minimize adverse effects and that take full advantage of opportunities to increase benefits.
The early, effective, knowledgeable involvement of the public to clarify issues and to aid in the development and evaluation of proposals in emphasized, and the effective use is stressed of expertise and resources both of the transportation agency and of other agencies with maximum flexibility and openess. The report also stresses the consideration of a range of transportation improvements involving various types of highway facilities, other models, transportation regulations, controls and constraints, and the no-build option.
A systematic evaluation process, and the documentation of work performed and decisions made are crucial, and institutional arrangements and decision-making are important. The planning approach and techniques presented here are based on the following findings: the overall process through which social, economic and environmental considerations are brought into transportation planning and decision-making is as important as the particular techniques used for predicting impacts; issues of social equity must be explicitly recognized and taken into account in transportation decision-making; different groups can be expected to have different interest and different priorities.
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