1 Transportation and Sustainable Development

Chapter overview

In this chapter, we introduce some of the challenges associated with transportation planning, particularly in the context of environmental issues such as climate change, and sustainable development strategies. We review the current state of environmental pollution and the transportation sector’s contribution to these problems. Additionally, we evaluate policies aimed at various goals, including reducing greenhouse gas (GHG) emissions, mitigating climate change and warming, and promoting environmental justice and equity. Finally, we conclude the chapter by discussing the challenges associated with these practices and how environmental justice, equity, and sustainable development are interconnected from a policy perspective.

THE CHALLENGES OF TRANSPORTATION IN THE US

This section examines some of the most relevant US transportation challenges from climate change and sustainable development perspectives.

• Problem 1: Transportation (driving) is the largest contributor to GHG emissions.

Energy used in land for residential activities accounts for 30-40% of the world’s energy consumption. Land-use planning can directly or indirectly affect the energy used by transportation. Research shows that when combined, transportation and housing energy use are responsible for about 62% of the world’s energy use and 55% of global greenhouse gas (GHG) emissions (Anderson et al., 2015). Several planning-related factors, such as population density, the spatial layout of the city, and access to transit, significantly affect the amount of energy consumed by residential and transportation needs. Accordingly, higher urban densities allow a larger population to reside in an urban area, providing commuters greater access to public transportation options. For instance, results from a 2016 study in Toronto, Canada, show that a higher population density reduces commuters’ miles traveled and therefore reduces the consumption of fossil fuels. This study reveals that commuter contribution to GHG emissions of a low-density suburban development is higher (by a factor of 2–2.5 partly) than in a high-density urban core development (Norman et al., 2006). Transportation scholars agree that in developed-world cities, suburban commuters use more fossil fuels and contribute more to GHG emissions than urban residents (Bastos et al., 2016; Marique & Reiter, 2012)

• Problem 2: U.S. cities are among the largest GHG emission producers in the world because of built environment-related factors such as lower density, fewer public transportation facilities, and poor access to public transit.

Figure 1.1 also shows the relationship between density and energy consumption for many cities in the world. What is evident from this graph is that U.S. cities are typically less dense and consume more energy for transportation.  This may be attributed to the predominance of commutes single-occupancy private vehicles. Low-density development and a lack of transit systems in most U.S. cities have created car-dependent cities.  However, European cities are denser and more compact and provide a variety of transportation modes. The graph depicts how much less energy is consumed for transportation in Europe and Asia. Thus, sustainable mobility is achievable when factors such as density, access to transit, availability of different modes of transportation, and shorter commute distances are realized.

On the other hand, in Latin America, as exemplified by Mexican cities, residents tend to have better access to transit along with denser communities; these cities use less transportation-related energy consumption than most U.S. cities (Figure 1.1). In Mexican cities, people use public transit and walk more than their US counterparts (Guerra et al., 2020). Therefore, cities in this part of the world have a lower impact on increasing GHG emissions and energy consumption than some low-density and car-dependent cities in America

SUSTAINABLE DEVELOPMENT POLICY SOLUTIONS FOR US CITIES

• Sustainable Development: What is sustainable development, and what are the 17 Sustainable Development Goals?
• Sustainable Mobility: How may sustainable mobility serve to enable the United Nations’ 17 Sustainable Development Goals?

Sustainable development

In terms of sustainable development, the United Nations (UN) has proposed 17 goals for achieving sustainable development, which are listed as follows (United Nations, 2015):

1. Ending all forms of poverty globally.
2. Promoting food security and nutrition through sustainable agriculture.
3. Promoting healthy life for all age groups.
4. Promoting equitable and inclusive education with lifelong opportunities.
5. Ensuring gender equality and promoting women’s rights.
6. Ensuring safe and sustainable water resources with the possibility of sanitation for all.
7. Providing affordable and sustainable energy for all.
8. Promoting economic growth that is sustainable and equitable and provides decent, full, and productive employment for all
9. Developing sustainable and resilient infrastructure along with innovative industrialization.
10. Reducing the gap of inequality globally.
11. Promoting livability of cities through inclusive design and development, safe and sustainable settlements.
12. Ensuring sustainable consumption and production patterns.
13. Developing feasible plans for fighting climate change.
14. Cautiously using resources such as oceans, seas, and all other marine resources in a sustainable manner.
15. Promoting sustainable use of ecosystems such as forests while reducing Biodiversity loss.
16. Ensuring equal access to justice within societies for everyone.
17. Promoting the means for establishing a global partnership for sustainable development across all countries and building an international coalition for realizing sustainable development (United Nations, 2015).

These Sustainable Development Goals recognize that sustainable development relies heavily on environmental sustainability policies that encourage green cities, sustainable transportation infrastructure, and effective actions to combat climate change. However, sustainable development cannot be achieved only by these environmental planning policies and solutions. Thus, ideals associated with more equitable and just societies, such as no poverty, quality education, and gender equality, are also significant and critical to truly achieving sustainable development goals. Incorporation of the UN SDGs into government plans and policies to eliminate poverty, reduce inequalities, and tackle climate change while creating partnerships with communities, NGOs (non-governmental organizations), and industry will further Sustainable development. Figure 1.2 thematically depicts the United Nations’ Sustainable Development Goals.

Sustainable development is not a simple concept and has a complex meaning that includes references to many different global and local problems. This concept and policy approach has evolved over the last four decades. In the 1980s, global leaders and policymakers defined it as “A development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (Keeble, B. R, 1987. p.20). Sustainable development was defined in relation to nature, economy, and society. However, when equity and justice issues are disregarded in sustainable development, the balance between economic, environmental, and social dimensions of sustainability is undermined (Agyeman, 2005; Agyeman et al., 2002).

Because extreme climate events, such as floods and droughts, are expected to exacerbate the current vulnerabilities and spatial inequities currently experienced by low-income families across the globe (Adger, 2006; Boone & Fragkias, 2012), scholars and planners have urged policymakers to raise justice and equity as the core principles of sustainable development (Agyeman, 2005). Recently, sustainability has been coupled with environmental justice to empower grassroots social movements of low-income communities to face the spatial injustices that disproportionately threaten them (Agyeman, 2005; Boone & Fragkias, 2012).

Also, because the urban poor tend to contribute little to greenhouse gas emissions but are disproportionately exposed to extreme climate events, climate justice emerges as another central component of the concept of sustainability (Adger, 2006; Steele et al., 2012). Finally, sustainability in transportation is linked with the concept of compact urban development (Davoudi, 2014). Urban density and transportation access determine how commuters get to places, use transportation energy, and contribute to greenhouse gas emissions (Davoudi, 2009; Norman et al., 2006; Stephan et al., 2011). Compact cities with resilient, robust, and multi-modal transportation systems may allow residents to commute efficiently to use the city’s services and opportunities (Gudmundsson & Höjer, 1996).

Sustainable transportation/mobility

Sustainable mobility, also known as sustainable transportation, is defined as different solutions and policies that 1) help to reduce GHG emissions, 2) decrease air pollution, and 3) provide an equitable transportation system (e.g., for low-income residents, disabled populations, and women). One way to achieve sustainable development goals is to have sustainable transportation that is environmentally friendly, affordable, accessible, and equitable for all. In the UN Sustainable Development Goals (SDGs), sustainable transportation is either directly mentioned or implied within several SDGs and targets. Sustainable transportation is also directly related to sustainable food security, energy consumption and conservation, health-related issues like pollution, economic growth and development, enhancing urban areas and population settlements, and promotion of infrastructure. The following graph provides a comprehensive explanation of the impacts of sustainable transportation on achieving the SDGs (Figure 1.3) (United Nations, 2023). To summarize, a transportation system is sustainable when it is safe, affordable, accessible, efficient, and resilient and minimizes carbon and other emissions.

SUSTAINABLE TRANSPORTATION POLICIES

Much can be learned from the outcomes of transportation policies implemented in other cities worldwide.  Effective transportation policies result in equitable access, climate mitigation, and reduction of GHGs.

Policies that Promote Access

Transportation-related policies that help to provide access to public transit for low-income residents lead to achieving sustainable development goals. An example is the city of Medellin, Colombia, where implemented policies have achieved SDGs through the transportation system. This example shows how the access of slum dwellers to different opportunities, such as education, jobs, and public services, is improved by transportation policies and infrastructure improvements (Galvin & Maassen, 2019). Another example of the implementation of sustainable transportation policies is the “Integrated BRT System” in Curitiba, Brazil. As a result of this policy, currently, “80% of travelers use the BRT system, and it carries around 2 million passengers per day. The BRT has 30 hybrid buses, reducing overall fuel needs by 35% and limiting pollutant emissions” (C40 Cities.org, 2016, p. 40).

Policies that Reduce GHGs

Policymakers in the United States have also introduced strategies such as fuel-efficient vehicles and electric cars to support sustainable transportation (Lutsey & Sperling, 2009; Tong & Azevedo, 2020). This strategy tends to reduce GHG emissions; however, these vehicles and the associated infrastructure (including ports and stations) are not accessible and affordable for disadvantaged and underserved commuters, such as minorities and low-income residents (Guerra et al., 2020). On the other hand, the difference between the use of public transport in Global South and American cities shows that this difference is related to the different ways that cities are formed. While in the U.S., suburbs provide housing for higher-income populations, in Mexico City and other Latin American cities, the low-income populations are usually pushed away to the edge of the cities (Monkkonen et al., 2018). Therefore, they usually cannot afford a car and must use formal or informal public transportation to access jobs and other opportunities (Cervero & Golub, 2007; Oviedo Hernandez & Titheridge, 2016).

Policies that Address Global Climate Change

The Paris Agreement on climate change is also related to sustainable transportation. Studies show that the U.S. is the second largest country after China contributing to GHG emissions (Figure 1.4). Therefore, countries like the United States must provide policies to control and mitigate GHG emissions. Also, by comparing the per-capita contribution of residents in the United States and China, we can conclude that the contribution of GHG emissions is significantly more critical in the U.S.  The impact of different countries and cities on Global Warming is different. While only 2% of the land is occupied by cities globally, they contribute to over 60% of global energy consumption, about 70% of GHG emissions, and about 70% of global waste (Habitat3.org, 2016). As shown in Figure 1.4, transportation contributes to the most GHG emission in the United States, which is the second largest GHG emitter in the world, after electricity and heat. Therefore, transportation plays a significant role in producing GHG in the U.S.

The impact of different countries and cities on global warming is different. On the other hand, while only 2% of the land is occupied by cities today, they contribute to over 60% of global energy consumption, about 70% of GHG emissions, and about 70% of global waste (Habitat3.org, 2016). As shown in Figure 1.7, transportation contributes to the most GHG emission in the United States, which is the second largest GHG emitter in the world, after electricity and heat. Therefore, transportation plays a significant role in producing GHG in the U.S.

Where Sustainable Development Policies Are Most Needed

Figure 1.5 shows that the three large contributors (China, the U.S., and the European Union countries) are responsible for around 40% of global emissions. The ten largest countries emit two-thirds of global GHG emissions. On the other hand, the other 100 countries produce only 4% of global emissions (Friedrich et al., 2020). This assessment reveals the inequities in the contribution of GHG emissions between developed and developing countries in the Global North and the Global South, respectively. Therefore, to combat climate change and mitigate GHG emissions, the role of the top 10 countries that produce the largest amount of GHG is more significant than others. While electricity and heat consumption in buildings are the most significant contributors to global GHG emissions, in China, the manufacturing sector is the most significant contributor, given the large industrial sector. On the other hand, transportation is the largest contributor to global warming in the United States due to the high car dependency in most American cities. From the beginning of recording and reporting of emissions in 1990, electricity, transportation, manufacturing, construction, and fossil fuel consumption were the biggest GHG emitters (around 73% of the total) in 2017 (Friedrich et al., 2020). Accordingly, since transportation plays a significant role in GHG emissions, there is a strong relationship between sustainable development and sustainable transportation. The following table summarizes different definitions, the effects/externalities of sustainable development, and the solutions to achieve sustainable development.

Source: Gudmundsson & Höjer, 1996

The primary role of transportation is to maximize mobility; however, transportation can have both positive and negative effects on people’s quality of life. The following table demonstrates the major effects of transportation on the quality of daily life.

In addition to what is mentioned in the above table, transportation can positively or negatively affect equity. While equal access to public transportation can result in a more equitable society, restricted public transit systems can add to inequalities.
An example of GHG emissions in Australia shows that the transportation sector contributes around 15.3% of GHG emissions in the country, of which road transport is responsible for 86%. Among road transport’s different sectors, passenger movement has the most significant share (Philp & Taylor, 2017). Figure 1.6 illustrates the GHG emissions and the contribution of transportation to GHG emissions in the world.

A comparison of the United States and Australia regarding the GHG emission related to transportation shows that while transportation is still one of the most significant contributors to GHG emission, in the U.S., the amount of GHG produced by transportation (Figure 1.7) is much higher than that produced in Australia.

Policies that Promote Low-Carbon Mobility

Therefore, several policies in terms of lowering carbon mobility have been discussed to manage the level of GHG emissions by the transportation sector and to mitigate its negative effect. These policies can be categorized by various aspects, including urban design and planning, Low Carbon Mobility (LCM) policy and behavior change, system and infrastructure, and innovative technology. These strategies need careful modeling, measuring, and monitoring to understand the implications for supporting sustainable urban development. Solutions such as using electric vehicles or congestion charging are among the most common solutions derived from these policies.
Additionally, there are methods to measure the benefits of sustainable transportation policies. Different factors should be considered when measuring the benefits of shifting from using private cars to using public transport (Gudmundsson & Höjer, 1996; Philp & Taylor, 2017). The factors that could support the transition to sustainable mobility in Global North countries are listed below.

• Urban design and transport integrations
• Behavior changes and public perceptions
• Technological development and adoption
• Modeling

Finally, there are also many implementation challenges of sustainable transportation policy, such as:

• Data collection and availability
• Integration
• Evaluation
• Urban planning and design
• Technological improvement
• Safety
• Equity for all

Conclusion

In summary, sustainable mobility or transportation refers to solutions and policies that reduce greenhouse gas emissions and air pollution and provide equitable access to transportation. From the sustainability and social justice perspective, a sustainable transportation system offers safe, affordable, accessible, efficient, and resilient access to mobility to all commuters, especially low-income residents. At the same time, sustainable transportation systems mitigate the contribution to GHG emissions because they use sustainable materials and non fossil fuels.

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