Role of Transportation in Sustainability
Mobility is an important part of daily life. We travel to get to work and school, to visit friends, to shop, and to have fun. The amount of time and distance in travel has significant implications for the environment, society, and the economy1. Each travel option available to us has an associated environmental impact, and we can actively reduce these impacts through the everyday travel choices we make. Providing energy efficient alternatives and encouraging the use of diverse modes of transport makes it possible for individuals to reduce their impact, while better planning and community design can greatly reduce the need to travel for day-to-day activities2. The transportation choices we make every day- both in supply and demand – have profound effects on sustainability.
When talking about the relative merit of different transportation modes in sustainability, people often refer to the transportation hierarchy3. The hierarchy illustrates that a sustainable transportation system has the largest numbers of people using low-impact modes of transportation such as walking and cycling. These modes require relatively little equipment, infrastructure, or fuel (short of food!), and have the least environmental impact. As you move down the hierarchy, modes require more fossil fuel and hard infrastructure such as roads4.
The most well-known definition of sustainability arose from the Brundtland Commission in 1987 and states that sustainable development “meets the needs of the present without compromising the ability of future generations to meet their own needs”5. Sustainability is widely recognized as having three components: social, economic, and environmental concerns, all of which must be addressed in working towards a sustainable future. Two visual models illustrate this concept6:
Legs of a Stool Some see all three as legs on a stool- life as we know it cannot be sustained without any one of them. Sometimes the seat of the stool is conceptualized as governance- what holds it all together.
Concentric Circles This conception relays the dependencies between the three concerns. Economic concerns are on top of or within Social concerns which are on top of or within Environmental concerns. Without the under/outerlying layer of the Environment, the Social and Economic concerns do not matter.
The transportation options available have profound social impacts. Transportation affects our health and safety, the ways we interact with one another, and the opportunities we have access to 7 8.
- Mobility Equity When there are no other options except private transportation modes (such as cars or bicycles), there are individuals who experience reduced mobility. They may be unable to use the vehicle, or often in the case of automobiles, unable to afford one. This creates a dichotomy between the mobility rich and the mobility poor. Providing public transit and improving walkability improves mobility equity.
- Accessibility Related to mobility equity, transportation systems also affect accessibility to opportunities. Opportunities include recreation, work destinations, social destinations, and shopping. Transportation vehicles can be designed to accommodate a wide variety of users, and services can be created to assist in the mobility of those with disabilities to improve access.
- Social Exclusion The mobility poor experience social exclusion in two ways. First, they are less able to travel to maintain social ties. Second, they are less likely to meet new people, as they cannot access public spaces or attend social events.
- Community Cohesion Dense, transit oriented, and walkable neighborhoods which have ample space for interaction enhance the sense of place and foster community cohesion. Communities with higher levels of social capital are more resilient, have better civic participation, and have lower rates of residential mobility.
- Physical Activity Physicians recommend at least 30 minutes of exercise every day. It is easy to get this by walking or cycling. However, without non-motorized options, people often have trouble getting daily activity.
- Air Quality Exhaust from vehicles worsens air quality. Individuals who live or work along arterials with heavy traffic may experience asthma, allergies, and general poor health.
- Safety and Accidents Vehicular accidents are a leading cause of death. Travel at high speeds endangers people both within the car and outside of it. Alternative modes such as transit, cycling, and walking are generally safer ways to travel.
For more information about the social impacts of transportation, see the SORT repository.
For information on Mobility Studies, check out the Mobilities Journal.
People are generally quite familiar with the environmental impacts of transportation. Because we as a society move people and goods so frequently, and such far distances, there are deep impacts on the environment9.
- Climate Change Greenhouse gases, especially carbon dioxide, are causing the earth’s climate to heat up. Transportation is a big producer of GHGs.
- Air Pollution/ Particulates Along with GHGs, exhaust from transportation vehicles release small particles which pollute the air. This affects biological health generally.
- Water Pollution Runoff from impervious surfaces such as roads and parking lots contains oil, gasoline, and other toxic chemicals. Often, this runoff ends up in natural waterways. This compromises aquatic ecosystems.
- Habitat Destruction/Degradation Transportation infrastructure requires space. Typically, that space will have been occupied by a variety of flora and fauna. Environmental impact statements are an attempt to anticipate the ecological implications of the project, but they cannot mitigate all damage.
- Animal Migration Routes High speed transportation systems such as rail and highways require a dedicated right-of-way. Unfortunately, this often cuts through habitat and migration routes for animals. They may be isolated from crucial ecosystems, or they may try to transverse the right-of-way and risk being hit.
There are many ways in which our transportation systems are inefficient. The way our economy is structured encourages bad transportation behavior. Under-valuing or over-valuing things can cause transportation demand which is detrimental to society and the environment10.
- Personal Income and Purchasing Power Individuals have different income levels. Some are able to afford a variety of transportation options. Others have very limited options based on what they can afford.
- External Costs of Transportation Some costs of using particular modes are not paid by the users. Automobile users often do not pay for parking, the environmental damage of pollution, or for the use of roads during peak periods.
- Fixed Costs Vs. Variable Costs Owning a car is very expensive. One must pay for registration, the lease, and insurance, all before taking it out on the road. However, using the car is relatively inexpensive with ownership because the only variable costs are gas, wear-and-tear, and parking/tolls. This encourages car owners to drive more than they need to.
- Energy Security Much of our transportation system depends on fossil fuels. There is only a limited quantity of oil, and we may have already reached a point where demand outstrips the discovery of new sources.
- Subsidization Much of our transportation system is subsidized. Taxes pay for roads and bridges, and parking is often paid for by land or business owners. This encourages inefficient behavior because the services are essentially free to the users.
- Induced Demand When transportation infrastructure is designed for private vehicles, individuals benefit from that. In an example of a highway, individuals are able to move further away from the city, but still commute to the business district. This transportation demand was effectively created by the infrastructure. By this logic, expanding the highway system only creates more demand, rather than alleviates it.
Transportation Demand Management
“Transportation Demand Management (TDM, also called Mobility Management) is a general term for strategies that result in more efficient use of transportation resources.”
- Victoria Transport Policy Institute’s Online TDM Encyclopedia, June 2007
The goal of TDM policies and programs are to reduce transportation demand generally, and to meet remaining demand with existing transportation infrastructure. This is different from transportation supply, which looks to meet transportation demand by providing more service and/or infrastructure. TDM is an important tool in working towards sustainability. TDM tools can be used to achieve social, environmental, and economic objectives.
Social Equity The U-Pass program at UBC gives all students unlimited access to TransLink transit services. The students have equal mobility and access to destinations across the greater Vancouver region.
Environmental Impact Offering End-Of-Trip Facilities on the UBC campus makes cycling to work or school easier. Cycling is a zero-emission vehicle, and each cyclist is one less car on the road.
Economic Efficiency By providing alternatives to driving, UBC has been able to reduce the number of surface parking stalls on campus. This has made room for more campus development such as classroom space, which has more value than parking. This also encourages denser development, which requires less transportation.
Land Use and Transportation Demand
If you lived right behind the grocery store, would you drive to get there? Of course not, you would walk. However, not many people live within walking distance of all their desired destinations. Sometimes, you have to take transit. Some places, you have to drive to get anywhere. This is a result of land use decisions: what goes where, and next to what.
Increasing Automobile and Transportation Demand11
Single-Family Homes Much of the available housing stock is single family homes. These sprawling neighborhoods are often far away from amenities such as shops, public space, and municipal buildings. The preeminence of this housing type has forced automobile dependency for many Canadian families.
Zoning Zoning, by definition, separates land uses. Residential is separated from commercial, requiring commuting. Industrial is separated from commercial, requiring shipping. People and goods need to get between these ‘zones’ and transportation becomes the only option.
Highway Development Building and expanding highways increases access to cheap land on the fringes of development. However, use of the fringe land requires transportation. Expanding the highway system creates more transportation demand by increasing the distance between origins and destinations.
Reducing Automobile and Transportation Demand12
Density When things are closer together, the distance between them is also shorter. This reduces the demand for transportation.
Walkability By making it easier to walk, such as installing sidewalks, or closing routes to automobiles, people are more likely to use non-motorized transportation. The concept of walkability can be integrated into the design of buildings and communities.
Mixed Use Density and walkability do not solve reduce transportation demand unless different land uses are within the same area. Commercial, residential (and sometimes even industrial) uses should be in the same area to meet the needs of residents.
Smart Growth Smart growth is based on the concept that we should live, work and play in complete communities. As new areas are built, care should be taken that a variety of housing options, appropriate jobs, amenities, and services are available.
Transit Oriented Development It is unreasonable to think that even in a mixed-use community, people would never travel outside of the community. Therefore, communities should be transit-oriented so that when individuals travel between communities it is by transit rather than automobiles.
1 Transport Canada. Retreived October 13, 2009.
2 United Nations Environment Programme. Energy Branch. Retrieved October 13, 2009.
3 Victoria Transport Policy Institute. TDM Encyclopedia. Retrieved October 13, 2009.
4 Transportation Alternatives. Retrieved October 13, 2009.
5 United Nations. Our Common Future. Retrieved October 13, 2009.
6 Fresh Outlook Fountation. Retrieved October 15, 2009.
7 Transport Canada. The Social Implications of Sustainable and Active Transport. Retrieved October 13, 2009.
8 Transport Canada. The Links between Public Health and Sustainable and Active Transportation. Retrieved October 13, 2009.
9 Statistics Canada. Human Activity and the Environment: Annual Report (2006). Retrieved October 13, 2009.
10 Victoria Transport Policy Institute. TDM Encyclopedia. Retrieved October 13, 2009.
11 Victoria Transport Policy Institute. TDM Encyclopedia. Retrieved October 15, 2009.
12 Victoria Transport Policy Institute. TDM Encyclopedia. Retrieved October 15, 2009.