Sustainable Transportation and TDM
Planning That Balances Economic, Social and Ecological Objectives
Victoria Transport Policy Institute
Updated 29 May 2015
This chapter discusses the concepts of sustainability, sustainable development and sustainable transportation, and how TDM can help achieve sustainability goals. Sustainability is a planning perspective that accounts for economic, social and environmental goals, including impacts that are indirect, difficult to measure, and distant in time and space. Sustainable transportation requires more comprehensive planning than what is commonly practiced. Sustainable planning can provide an opportunity to identify strategies that can help achieve multiple goals. TDM tends to support sustainability objectives, and sustainability planning tends to support TDM implementation.
The earth provides enough to satisfy every person’s need but not every person’s greed…When we take more than we need we are simply taking from each other, borrowing from the future, or destroying the environment and other species.
Mahatma Gandhi, Principle of Enoughness
There is growing interest in the concepts of sustainability, sustainable development, and sustainable transport. Sustainability reflects one of the most fundamental human desires supported by virtually all philosophies and religions: to create a better future world. It provides guidance for long-term, strategic decision-making. Sustainability emphasizes the integrated nature of human activities and therefore the importance of comprehensive Planning that coordinates between sectors, jurisdictions and groups. This is an important change because existing institutions are often poorly suited to address complex, long-term problems.
There is no universally accepted definition of sustainability, sustainable development or sustainable transport (Beatley, 1995). Some definitions are listed below.
A sustainable transport system is one that is accessible, safe, environmentally-friendly, and affordable.
Sustainable development “meets the needs of the present without compromising the ability of future generations to meet their own needs.”
“The goal of sustainable transportation is to ensure that environment, social and economic considerations are factored into decisions affecting transportation activity.”
A sustainable transportation system is “one in which fuel consumption, vehicle emissions, safety, congestion, and social and economic access are of such levels that they can be sustained into the indefinite future without causing great or irreparable harm to future generations of people throughout the world.”
“…sustainability is not about threat analysis; sustainability is about systems analysis. Specifically, it is about how environmental, economic, and social systems interact to their mutual advantage or disadvantage at various space-based scales of operation.”
The Environmental Directorate of the OECD defines environmentally sustainable transportation as, “transportation that does not endanger public health or ecosystems and that meets needs for access consistent with (a) use of renewable resources that are below their rates of regeneration, and (b) use of non-renewable resources below the rates of development of renewable substitutes.”
Sustainable planning means that local, short-term decisions are consistent with strategic, regional and global, long-term goals.
A sustainable transportation system is one that:
· Allows the basic access and development needs of individuals, companies and society to be met safely and in a manner consistent with human and ecosystem health, and promotes equity within and between successive generations.
· Is Affordable, operates fairly and efficiently, offers a choice of transport mode, and supports a competitive economy, as well as balanced regional development.
· Limits emissions and waste within the planet’s ability to absorb them, uses renewable resources at or below their rates of generation, and uses non-renewable resources at or below the rates of development of renewable substitutes, while minimizing the impact on the use of land and the generation of noise.
The Transportation Association of Canada proposes that a sustainable transportation system has the following characteristics:
(a) in the natural environment:
· limit emissions and waste (that pollute air, soil and water) within the urban area’s ability to absorb/recycle/cleanse;
· provide power to vehicles from renewable or inexhaustible energy sources. This implies solar power over the long run; and
· recycle natural resources used in vehicles and infrastructure (such as steel, plastic, etc.).
(b) In society:
· provide equity of access for people and their goods, in this generation and in all future generations;
· enhance human health;
· help support the highest quality of life compatible with available wealth;
· facilitate urban development at the human scale;
· limit noise intrusion below levels accepted by communities; and
· be safe for people and their property.
(c) In the economy:
· Be financially affordable in each generation;
· Be designed and operated to maximize economic efficiency and minimize economic costs; and
· help support a strong, vibrant and diverse economy.
Sustainability has been identified as “The capacity for continuance into the long term future.” Anything that can go on being done on an indefinite basis is sustainable. Anything that cannot go on being done indefinitely is unsustainable. The practices of the world's populace are currently unsustainable.
If we do not reach a point where our activities are sustainable, then we will eventually consume all available resources and generate a level of pollution that will mean the earth is no longer capable of sustaining human life.
Within a sustainable society it is also expected that every individual will have a right to “a better quality of life,” which would include having adequate food, education, employment and housing, and for this to occur stable economic growth will be required. The challenge is to decouple social progress and economic growth from resource depletion and adverse environmental impacts.
The UK Government has set out the following 4 pillars of sustainability:
· Social progress for everyone.
Concern about sustainability can be considered a reaction to increased specialization in the way institutions are organized, and the tendency of decision-makers to focus on easily measured goals and impacts, while ignoring those that are indirect or more difficult to measure (Measuring Transportation). Conventional planning often reflects a “reductionist” approach, in which a particular organization or individual is responsible for solving narrowly-defined problems. This may be appropriate in some situations, but it often results in solutions to one problem that exacerbate other problems, or failure to implement solutions that provide modest but multiple benefits. Sustainable decision-making can therefore be described as Comprehensive Planning that considers a variety of goals and impacts regardless of how difficult they are to measure. Sustainable planning and economics often refer to the triple bottom line, meaning consideration of economic, social and environmental impacts.
Conventional planning typically uses a 5-20 year time-frame, less than one generation. Sustainability incorporates concerns about long-term risks, such as depletion of resources, harmful pollution and climatic change that may harm people decades or even centuries in the future. This reflects concerns over “intergenerational equity” (i.e., being fair to future generations). But if future equity and environmental quality are concerns, it makes little sense to ignore equity and environmental impacts that occur during this generation to people in other regions or cultures. Thus, sustainability ultimately reflects the goals of Equity, ecological integrity and human welfare, regardless of time or location.
Sustainable economics maintains a distinction between growth (increased quantity) and development (increased quality). Growth assumes that the goal is to replicate what currently exists at a larger scale – bigger is better. Development assumes that the goal is improvement, which may involve expansion or contraction to an optimal scale.
Economic growth focuses primarily on market activities, while economic development also considers non-market social and ecological activities (Daly 1996). Sustainable development focuses on social welfare outcomes, such as education and health, rather than relying on material wealth as an indicator of development. Unlike neoclassic economics, sustainable economics does not strive for ever increasing consumption, but rather for sufficiency. As a result, it questions common economic indicators such as Gross Domestic Product (GDP), which measure the quantity but not the quality of market activities. For example, GDP counts medical costs and environmental cleanup as positive economic activity, but assign no positive value to actions that prevent illness or environmental degradation. Sustainable development indicators attempt to take into account qualitative and non-market values (Cobb, Halstead and Rowe 1998).
Conventional planning tends to ask, “Does it work?” Sustainability planning tends to ask “Does it fit?” That is, sustainability planning places greater emphasis on how individual decisions fit into the overall context of total long-term goals and objectives.
Conventional economics defines people primarily as consumers, with the implication that the way to improve social welfare (i.e., to make people better off) is too maximize consumption of market goods (as reflected in GDP). Sustainable economics recognizes that people are also community members, residents, and citizens who also value non-market goods and community resource. For example, many people value friendship, security and tradition, and will forego material wealth to achieve them. The relative value of these non-market goods tends to increase as people become wealthier, since their most basic physical needs are already met. For example, an increase of $1,000 in annual income tends to provide far greater benefit to somebody who only earns $10,000 a year than to somebody earning $100,000 a year, since the wealthier person already has their basic material needs met (this is called declining marginal benefit). As a result, as a region becomes more economically developed and wealthier, the relative value of additional market goods tends to decline, while the relative value of non-market goods tends to increase.
Sustainability is sometimes defined narrowly. Some studies of sustainability focus on long-term resource depletion and air pollution problems, on the grounds that they represent the greatest risk and are prone to being neglected by conventional planning (TRB 1997). But sustainability is increasingly defined more broadly to include the range of issues listed in Table 1.
Table 1 Sustainability Issues
Trade and business activity
Quality of life
Avoidance of irreversibility
This table lists various sustainability issues.
Although Table 1 implies that each issue fits into a specific category, in practice they often overlap. For example, pollution prevention is an environmental concern, but it also protects human health (a social concern) and is important for fishing and tourism industries (economic concerns). Sustainable planning reflects the realization that impacts and objectives often interact, so solutions must reflect integrated analysis.
Who Is More Sustainable?
Who is more sustainable, somebody who drives a fuel-efficient vehicle high annual miles, or somebody who drives an inefficient vehicle low annual miles?
If sustainability is defined only in terms of fuel efficiency and related emissions, it can be achieved by driving a fuel efficient vehicle, such as a 60 mile-per-gallon (MPG) hybrid car. However, such a car does not reduce traffic congestion or the barrier effect (delay and risk to pedestrians and cyclists), road and parking requirements, accident risk, or sprawl. A motorist who lives in a more accessible location and relies on alternative modes as much as possible (for example, commuting by bicycle, carpool or transit most days) and so drives an average efficiency vehicle low annual miles, consumes a similar amount of fuel, but imposes far lower costs on society overall.
Principles reflect fundamental goals and practices. Below are basic principles of sustainability planning.
· Comprehensive Analysis. Sustainability requires planning that considers economic, social and environmental impacts, including those that are indirect, long-term and nonmarket. This requires adequate information and evaluation tools that allow stakeholders and decision-makers to understand the effects of their decisions.
· Integrated and Strategic Planning. Sustainability planning requires that individual decisions support a community’s long-term strategic objectives. For example, transportation planning decisions should be subordinate to strategic economic, social and land use plans.
· Focusing on Goals, Performance and Outcomes. Sustainability requires that planning be based on goals and outcomes, such as improved social welfare, ecological health and access. It does not limit analysis to financial impacts and market activities.
· Consideration of Equity. Sustainability emphasizes that Equity impacts should be considered in decision-making, including those that are indirect and long-term (imposed on future generations).
· Market Principles. Market Principles include consumer choice, full-cost pricing and economic neutrality can support sustainable outcomes. This requires Market Reforms that eliminate incentives to over-use of natural resources and to degrade the environment.
· Precautionary Principle. Sustainability supports the Precautionary Principle, which emphasizes the importance of incorporating risks in decision-making and favoring policies that minimize such risks when possible. It values Resilience.
· Conservation Ethic. Sustainability favors solutions that increase efficiency and reduce resource consumption, due to uncertainties about future market conditions and environmental impacts.
· Transparency, Accountability and Public Involvement. Sustainability requires a clearly defined, transparent planning process, adequate opportunities for stakeholder to become informed about issues and be involved in decision-making, and good communication between professionals and the general public.
Many organizations have developed recommended best practices for sustainable planning. The U.K. Royal Academy of Engineering provides the following principles of Engineering for Sustainable Development (RAE 2005). See the report for detailed information on these principles.
1. Look beyond your own locality and the immediate future
2. Innovate and be creative
3. Seek a balanced solution
4. Seek engagement from all stakeholders
5. Make sure you know the needs and wants
6. Plan and manage effectively
7. Give sustainability the benefit of any doubt
8. If polluters must pollute … then they must pay as well
9. Adopt a holistic,‘cradle-to-grave ’approach
10. Do things right,having decided on the right thing to do
11. Beware cost reductions that masquerade as value engineering
12. Practice what you preach.
Various indicator sets have been proposed and applied to evaluate sustainability. They expand on existing indicators, such as GDP, to account for diverse social goals and objectives (Redefining Progress; Litman 2011). These include specific, measurable indicators that reflect progress toward community development objectives. Table 2 is an example of a Genuine Progress Indicator developed for Alberta, Canada. Other regions, goals and analysis perspectives may require somewhat different indicators.
Table 2 Sustainability Indicators (Pembina Institute 2001)
Economy, GDP and Trade
Economic growth (GDP)
Personal Consumption Expenditures, Disposable Income and Savings
Money, Debt, Assets and Net Worth
Income Inequality, Wealth, Poverty and Living Wages
Public and Household Infrastructure
Weekly wage rate
Paid work time
Parenting and eldercare
Human Health and Wellness
Substance Abuse: Alcohol, Drugs and Tobacco
Drug use (youth)
Auto Crashes and Injuries
Intellectual & Knowledge Capital
Oil and gas reserve life
Parks and Wilderness
Parks and wilderness
Fish and Wildlife
Fish and wildlife
Wetlands and Peatlands
Water Resource and Quality
Energy Use Intensity and Air Quality
Energy use intensity
Air quality-related emissions
Greenhouse gas emissions
Carbon budget deficit
Municipal and Hazardous Waste
This table summarizes Genuine Progress Indicators used to evaluate sustainability.
Transportation facilities and activities have significant sustainability impacts, including those listed in Table 3. As a result, strategies that increase transportation system efficiency and reduce negative impacts from transportation are among the most effective ways to make progress toward sustainability objectives.
Table 3 Transportation Impacts on Sustainability
Transportation facility costs
Consumer transportation costs
Depletion of non-renewable resources
Inequity of impacts
Human health impacts
This table lists impacts that transportation activities tend to have on sustainability objectives.
Because transportation activities have so many impacts related to sustainability, it is important to identify strategies that help achieve multiple objectives, and avoid those that solve one transportation problem but exacerbate others (Comprehensive Planning). For example, a policy or program that reduces traffic congestion but increases air pollution emissions or crashes cannot be considered a sustainable solution. Similarly, a strategy that reduces energy consumption and air pollution emission, but increases traffic congestion, crashes and consumer costs is not necessarily a sustainable strategy. The most sustainable strategies are those that simultaneously help reduce traffic congestion, pollution, crashes and consumer costs, increase mobility options for non-drivers, and encourages more efficient land use patterns, or at least avoid contradicting these objectives (Win-Win Transportation Solutions).
Conventional planning tends to assume that transport progress is linear, consisting of newer, faster modes that displace older, slower modes as illustrated below. This series model assumes that the older modes are unimportant, and so, for example, there is no harm if increasing automobile traffic causes congestion delay to public transit or creates a barrier to pedestrian travel. From this perspective it would be backward to give public transit or walking Priority over automobile travel.
Walk è Bicycle è Train è Bus è Automobile è Improved Automobiles
Sustainable reflects a parallel model, which assumes that each mode can be useful, and strives to create balanced transport systems that use each mode for what it does best. Transport progress therefore involves improving all useful modes, not just the newest mode, as illustrated below. For example, in many cities the most beneficial transportation strategies may involve Improving Walking and Cycling, Support for Public Transit Use, and Restricting Automobile Traffic in congested urban areas. It does not assume that faster, motorized modes should have priority over slower modes, or that increased travel speed is necessarily more important than qualitative factors such as comfort, safety and equity.
Walk è Improved Walking Conditions
Bicycle è Improved Cycling Conditions
Train/Bus è Improved Public Transit Service
Automobile è Improved Automobile Travel Conditions
Accessibility- Versus Mobility-based Transport Planning (Litman 2003)
Accessibility (or just access) refers to people’s ability to reach desired goods, services, activities and destinations (together called opportunities). For example, a stepladder provides access to a high shelf, a store provides access to goods, and a library or computer provides access to information. Access is the ultimate goal of most transportation, excepting the small portion of travel in which movement is an end in itself, (e.g., cruising, historic train rides, jogging, etc.).
Many factors can affect accessibility, including mobility (physical movement), road and path connectivity, land use patterns (the location of activities), and mobility substitutes (telecommunications and delivery services). The affordability, information availability, and even the social acceptability of transport options, can also affect overall accessibility.
Conventional planning often evaluates transport system performance based primarily on mobility (using indicators such as traffic speed and vehicle operating costs), ignoring other accessibility factors and improvement options. For example, with mobility-based planning, the only practical solution to traffic congestion is to expand roadway capacity. Accessibility-based planning allows other solutions to be considered, including improvements to alternative modes, more accessible land use patterns, and improvement to mobility substitutes. Accessibility-based transport planning tends to support sustainability by expanding the scope of analysis and supporting more resource-efficient solutions. As a result, as much as possible, sustainable transportation indicators should reflect accessibility-based planning.
Sustainability and sustainable transportation are difficult to measure directly, so various Performance Indicators are used to evaluate them. Some are relatively narrow, focusing on just a few impacts, such as air pollution emissions, while others attempt to represent a broader range of economic, social and environmental objectives (Gilbert and Tanguay 2000; Litman 2009 and 2011). Below are examples of indicators.
· Quality of overall Accessibility (ability to reach desired goods, services and activities). More is better.
· Land Use Mix - Number of job opportunities and commercial services within 30-minute travel distance of residents. Higher is better.
· Land use accessibility - Average number of basic services (schools, shops and government offices) within walking distance of residences. Higher is better.
· Children’s accessibility - Portion of children who can walk or bicycle to Schools, shops and parks from their homes. Higher is better.
· Electronic accessibility - Portion of population with Internet service (Telework). Higher is better.
· Commute speed - Average commute travel time. Lower is better, particularly for disadvantaged populations.
· Transport diversity - Variety and quality of transport Options available in a community. Higher is better.
· Mode split - Portion of travel made by walking, cycling, rideshare, public transit and telework. Higher is better.
· Transit service – Public transit service quality, including coverage (portion of households and jobs within 5-minute walking distance of 15-minute transit service), service frequency, comfort (portion of trips in which passenger can sit and portion of transit stops with shelters), affordability (fares as a portion of minimum wage income), information availability, and safety (injuries per billion passenger-miles) (Transit Evaluation).
· Motor Transport Options - Quantity and quality of airline, rail, public transit, ferry, rideshare and taxi services. Higher is better.
· Congestion delay - Per capita traffic Congestion delay. Lower is better.
· Consumer Transport costs - Portion of household expenditures devoted to transport (Transport Costs). Lower is better.
· Affordability - Portion of household expenditures devoted to transport, including vehicle expenses, fares, residential parking costs, and taxes devoted to transport; particularly by people who are economically, socially and physically disadvantaged. Lower is better, particularly for disadvantaged populations.
· Facility costs - Per capita expenditures on roads, traffic services and parking facilities (Transport Costs). Lower is better.
· Freight and commercial transport efficiency – Speed, quality and affordability of Freight and commercial transport. Higher is better.
· Delivery services - Quantity and quality of delivery services (international/intercity courier, and stores that offer delivery). Higher is better.
· Market principles - Degree to which transport systems reflect Market Principles, including prices that reflect full costs and neutral tax policies. Higher is better.
· Planning Practices - Degree to which transport institutions reflect Least-cost planning and investment practices. Higher is better.
· User rating - Overall satisfaction rating of transport system and services by users (Surveys). Higher is better.
· Citizen involvement - Public involvement in transport Planning process. Higher is better.
· Crash costs - Per capita crash fatalities, disabilities and monetized Crash Costs. Lower is better.
· Planning process - Range of solutions considered in transport Planning. Higher is better.
· Health and fitness - Portion of population that regularly uses active transport modes (walking and cycling). Higher is better.
· Community Livability - Degree to which transport activities increase community livability (local environmental quality). Higher is better.
· Cultural Preservation - Degree to which cultural and historic values are reflected and preserved in transport planning decisions. Higher is better.
· Basic Access – Quality of transport to access socially valuable activities such as medical services, education, employment and essential shopping, particularly for disadvantaged populations.
· Horizontal Equity (fairness) - Degree to which prices reflect full costs unless a subsidy is specifically justified (Equity). Higher is better.
· Progressivity - Degree to which transport policies make lower-income people relatively better off (Equity). Higher is better.
· Mobility for non-drivers - Quality of accessibility and transport services for non-drivers (Equity). Higher is better.
· Mobility for people with disabilities) - Quality of transport facilities and services for people with disabilities, such as wheelchair users and people with visual impairments (Universal Design). Higher is better.
· Nonmotorized transport - Quality of walking and cycling conditions (Non-motorized Evaluation). Higher is better.
· Climate change emissions - Per capita fossil fuel consumption, and emissions of CO2 and other climate change emissions (Energy and Emission Reductions). Lower is better.
· Other air pollution - Per capita emissions of “conventional” air pollutants (CO, VOC, NOx, particulates, etc.) (Energy and Emission Reductions). Lower is better.
· Noise pollution - Portion of population exposed to high levels of traffic noise. Lower is better.
· Water pollution - Per capita vehicle fluid losses. Lower is better.
· Land use impacts - Per capita land devoted to transportation facilities (Land Use Evaluation). Lower is better.
· Habitat protection - Preservation of high-quality wildlife habitat (wetlands, old-growth forests, etc.) from loss due to transport facilities and development (Land Use Evaluation). Higher is better.
· Roadway aesthetic conditions (people tend to be more inclined to care for environments that they consider beautiful and meaningful).
Sustainability objectives have several implications for transport planning.
Sustainable transportation planning requires a paradigm shift: a fundamental Change in the way people think about and solve problems (Litman 1999; ADB 2009). It requires more comprehensive analysis of impacts, consideration of indirect and cumulative impacts, consideration of demand management solutions, and public involvement in transportation decision-making. It involves Prioritizing Transportation to give higher value trips and lower cost modes priority over lower value, higher cost trips.
Automobile dependency is defined as high levels of automobile use, automobile oriented land use, and a lack of travel alternatives (Newman & Kenworthy, 1999). Automobile dependency imposes a number of economic, social and environmental costs (Litman, 2000), and results in part due to distortions in transportation and land use markets (Market Principles) (TRB, 1997). Sustainable transportation requires reducing these distortions and encouraging the development of a more balanced transportation system (Evaluating Transportation Choice). Transportation Market Reforms that correct market distortions which cause excessive automobile use and automobile oriented land use patterns can increase Economic Development while also achieving social and environmental objectives.
Equity is a fundamental goal of sustainable development. Sustainable development reflects a desire to consider the impacts that our current decisions could have on future generations, called intergenerational equity. Sustainable transportation therefore requires that broad equity analysis be incorporating explicitly in transportation planning (Evaluating TDM Equity).
Sustainability requires that transportation facilities (roads, parking lots, transit systems, airports, etc.) be designed and operated to encourage use of sustainable modes, to support long-term land use objectives (such as preserving greenspace), to maximize resource efficiency and minimize waste in construction and use, and to operate efficiently over the long term.
Transportation patterns can be affected significantly by land use patterns (Land Use Impacts on Transportation). In particular, low density development, hierarchical street patterns, generous road and parking capacity, and automobile oriented site design tends to increase automobile dependency, leading to high levels of per capita motor vehicle mileage and a reduction in the quality of travel alternatives (transit, walking and cycling). Many experts conclude that sustainable transportation requires more Accessible land use (Newman and Kenworthy, 1999).
Sustainable transportation planning tends to be particularly important in lower-income, Developing Regions, since they have more limited resources, tend to rely more on alternative travel modes, and are currently making critical planning decisions which will determine the type of transportation system they will have in the future. Sustainability planning tends to favor more multi-modal transportation planning and Smart Growth, in order to avoid excessive Automobile Dependency, particularly in economically developing regions.
Many strategies have been proposed to create more sustainable transportation. Most involve either technical innovation or Transportation Demand Management. Sometimes these are presented as mutually exclusive (i.e., one approach or the other), but most objective research indicates that a combination of strategies is needed to achieve sustainability goals. For example, fuel efficient and alternative fueled vehicles can help achieve resource conservation and pollution reduction objectives, but demand management is needed to address other objectives, such as facility cost savings and improved travel choices for non-drivers.
Most analysis suggest that Transportation Demand Management is essential for achieving more sustainable transportation, although the term “Transportation Demand Management” is not always used. Some TDM strategies, called “No regrets” or Win-Win Transportation Solutions, help achieve a combination of economic, environmental and social objectives, and so are justified regardless of uncertainty over the value placed on impacts such as climate change and inequity.
Economic efficiency and resource conservation are important principles sustainability. This suggests that TDM strategies that reflect Market Principles, encourage more resource-efficient travel choices, or result in more efficient land use tend to support sustainability. TDM can also help achieve Livability objectives such as increased local environmental quality and community cohesion.
Efficient Land Use
Incorporating sustainability principles, objectives and evaluation criteria into transportation decision-making can support increased implementation of TDM, and greater coordination between transportation and land use planning.
Three fellows were sitting at a bar, and their conversation turns to collectables. One man describes his coin collection. “I have more than 2,000 coins from every country in the world, including several that are quite rare. My collection is valued at over $25,000. I keep it in a high-security cabinet.”
The second man brags about his book collection. “I have more than 400 antique books, including several signed first editions. My collection is valued at over $50,000. I keep them in a climate-controlled room in my house.”
The third man say, “I have the world’s largest seashell collection, including countless unique specimens. My collection is considered priceless. I keep it on beaches all over the world.”
For more information on issues related to sustainable development see Evaluating TDM, TDM Planning, Comprehensive TDM Evaluation, Measuring Transportation, Evaluating TDM Equity, Transportation Affordability, TDM and Economic Development, Transportation Costs, Asset Management, TDM in Developing Regions, Market Principles, Evaluating Pricing Strategies and Evaluating Transportation Choice.
Association of State Highway and Transportation Officials (AASHTO) has
acknowledged the need to change current transport planning practices to
incorporate sustainability objectives, as discussed in the report Transportation:
Invest in Our Future. It states, “America’s transportation system has
served us well, but now faces the challenges of congestion, energy supply,
environmental impacts, climate change, and sprawl that threaten to undermine
the economic, social, and environmental future of the nation. With 140 million
more people expected over the next 50 years, past practices and current trends
are not sustainable. To meet the transportation needs of the present and pass
on a better world to our children and grandchildren, it is necessary to expand
the transportation network’s capacity while simultaneously reducing the
environmental footprint of the system,”
The report urged transportation decision makers to adopt the so-called “triple bottom line” approach to sustainability by evaluating performance on the basis of economic, social, and environmental impacts and allocating equal consideration to these driving forces. The specific elements of the triple bottom line approach and the steps required to achieve them can be summarized as follows:
In 2005 Seattle Mayor Greg Nickels established a Green Ribbon Commission that included a wide variety of stakeholders and experts to recommend climate protection actions for the Seattle community to meet or beat the Kyoto target. In 2006 the Commission released a report and recommendations, which include the following strategies to reduce automobile use (plus other strategies to reduce emissions in other ways):
· Increase the Supply of Frequent, Reliable and Convenient Public Transportation
· Significantly Expand Bicycling and Pedestrian Infrastructure
· Lead a Regional Partnership to Develop and Implement a Road Pricing System
· Implement a New Commercial Parking Tax
· Expand Efforts to Create Compact, Green, Urban Neighborhoods
Along with their recommendations the Commission offered these observations:
· Success will require a deliberate, sustained, community-wide effort. And, since cars and other transportation sources are the largest source of climate pollution in our area, we will need strong regional collaboration as well.
· The actions and investments needed to rein in Seattle’s climate pollution will, at the same time, make our community healthier and more livable, for example, by reducing traffic congestion and toxic air pollution from diesel emissions.
· In addition, reducing our reliance on fossil fuels increases our energy independence, keeps more money circulating in the local economy and supports local and regional economic development.
· The road to a more climate-friendly community is paved with economic opportunities, including cost-savings from energy efficiency measures for our families and businesses—especially in light of rising and volatile energy prices—and new business prospects for our companies and entrepreneurs.
· Implementing these recommendations requires a significant investment of time and money by the community. But we believe the price tag is dwarfed by the cost to our community of not taking additional action.
· Finally, meeting the Kyoto target here—and, more important, transforming Seattle into the nation’s most climate-friendly city—is an extraordinary challenge. But our community has rallied to meet such challenges in the past. With Seattle’s unique mix of eco-intelligence and entrepreneurial zeal, we will meet and exceed the goal.
The New Zealand Transport Agency is developing a comprehensive benchmarking system to evaluate transport system performance. This will be used to monitor trends and compare cities. It identified the following ten Key Performance Indicators (KPIs):
· Traffic congestion indicator
· Travel mode share
· Public transit ridership
· Number and size of Park & Ride facilities
· Passenger kilometers traveled by public transport
· Road network length
· Population and employment density
· Parking density
· Cost of travel
· Travel personal security
· Road accident fatalities and injuries
· Vehicle harmful emissions
· Vehicle fuel consumption
· Vehicle occupancy
This report by the United Nations Environment Programme report, Towards a Green Economy: Pathways to Sustainable Development and Poverty Eradication, advocates economic development policies that increase resource efficiency and reduce pollution emissions. This will require a fundamental shift in investment patterns, based on avoid-shift-improve principles, which include reducing trips through integrated transport and land use planning, shifting to more efficient modes of transport like public and non-motorized modes, and improving vehicles and fuels to reduce urban air pollution and emissions. This research indicates that investment in public transit and greener vehicles generates significant economic returns as well as improving economic opportunity.
A special issue of the Journal of Urban Technology (Perl 2007) examines the paradigm shifts needed in urban transportation and land use planning to prepare for riding energy costs and to achieve sustainability objectives. The analysis indicates that sustainability objectives can be achieved through a combination of transportation and land use policy changes that reduce per capita transportation energy consumption, and create cities that better meet human needs, but that this requires fundamental changes in policy analysis and planning practices.
Leading experts recommend the following general principles to create more integrated and efficient local decision-making in the European Union:
1. Establish and enforce strategic (integration and with a long term perspective) visions, planning ability, capacity to use a wider and more innovative range of tools.
2. Promote management skills to develop participatory and proactive processes, involving all relevant stakeholders, and to implement local strategic planning, influencing and promoting the adoption of self – regulated behaviour from all the partners.
3. Consider and reflect upon national/local specificity and differences, being aware of new urban dynamics and of recent and relevant trends (such as increasing liberalisation of the environmental markets, globalisation of pressures, the need for urban renewal, etc.).
A study evaluated the sustainability of transportation trends in San Antonio, Texas, including per capita vehicle travel, consumer costs, traffic fatalities, energy consumption and pollution emissions (Barker 2005). Compared with other cities, San Antonio is found to be less sustainable. The study identifies factors that contribute to high levels of per capita vehicle travel, including development patterns, road density, jobs/housing balance and transit supply. The author identifies various strategies that could be applied to increase sustainability.
ADB (2009), Changing Course: A New Paradigm for Sustainable Urban Transport, Asian Development Bank (www.adb.org); at www.adb.org/Documents/Books/Paradigm-Sustainable-Urban-Transport/new-paradigm-transport.pdf.
ADB (2010), Reducing Carbon Emissions from Transport Projects, Asian Development Bank (www.adb.org); at www.adb.org/evaluation/reports/ekb-carbon-emissions-transport.asp.
William G. Barker (2005), “Can A Sustainable Transportation System Be Developed for San Antonio, Texas,” Transportation Research Record 1924, Transportation Research Board (www.trb.org), pp. 120-128; http://trb.metapress.com/content/k86304w451160775.
Timothy Beatley (1995), “The Many Meanings of Sustainability,” Journal of Planning Literature, Vol. 9, No. 4, May, pp. 339-342.
Daniel Bongardt, Dominik Schmid, Cornie Huizenga and Todd Litman (2011), Sustainable Transport Evaluation: Developing Practical Tools for Evaluation in the Context of the CSD Process, Commission on Sustainable Development, United Nations Department Of Economic And Social Affairs (www.un.org); at www.un.org/esa/dsd/resources/res_pdfs/csd-19/Background%20Paper%2010%20-%20transport.pdf.
Booz Allen Hamilton (2014), Sustainability as an Organizing Principle for Transportation Agencies, Strategic Issues Facing Transportation Volume 4, NCHRP 750, TRB (www.trb.org); at http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_750v4.pdf.
Brundtland Commission (1987), Our Common Future, Oxford University Press.
Cambridge Systematics (2009), Performance Measurement Framework for Highway Capacity Decision Making, Strategic Highway Research Program (SHRP) Report S2-C02-RR, TRB (www.trb.org); at http://sites.google.com/site/shrpc01.
Center for Transportation Excellence (http://environment.transportation.org) is an AASHTO program to support more environmentally responsible transport planning, including sustainability.
Clifford Cobb, Ted Halstead and Jonathan Rowe (1999), The Genuine Progress Indicator, Redefining Progress (www.rprogress.org).
CST (2005), Definition and Vision of Sustainable Transportation, Canadian Centre for Sustainable Transportation; at http://cst.uwinnipeg.ca/documents/Defining_Sustainable_2005.pdf.
Herman Daly (1996), Beyond Growth; Economics of Sustainable Development, Beacon Press (www.beacon.org).
EU Mobility and Transport (http://ec.europa.eu/transport) provides statistical information and research reports on transportation facilities, funding, activity and impacts for European Union countries. The EU Transport Scorecard (http://ec.europa.eu/transport/facts-fundings/scoreboard) provides information for comparing and evaluating transport system performance for each country.
European Commission (2002), Towards More Integrated Implementation Of Environmental Legislation In Urban Areas, Working Group on Integrated Implementation of Environmental Legislation (WG/IIEL), European Commission (DG Environment), (http://europa.eu.int/comm/environment/urban/pdf/0302finalreport.pdf).
FHWA (2010), Livability in Transportation Guidebook: Planning Approaches that Promote Livability, FHWA-HEP-10-028, Federal Highway Administration. USDOT (www.fhwa.dot.gov); at www.fhwa.dot.gov/livability/case_studies/guidebook.
FHWA (2011), Transportation Planning for Sustainability Guidebook, Federal Highway Administration (www.fhwa.dot.gov); at www.fhwa.dot.gov/hep/climate/resources.htm#sustain.
Global Reporting Initiative (www.globalreporting.org) is an international organization to develop, promote, and disseminate standard framework for sustainability reporting.
Global Transport Intelligence Initiative (www.slocat.net/key-slocat-prog/466) is a programs by international program organizations involved in the collection, analysis and dissemination of data on transport in the developing countries.
GPI (2008), GPI Transportation Accounts: Sustainable Transportation in Halifax Regional Municipality, GPI Atlantic (www.gpiatlantic.org); at www.gpiatlantic.org/pdf/transportation/hrmtransportation.pdf.
Ellen Greenberg (2008), “Sustainable Streets: An Emerging Practice,” ITE Journal, Vol. 78, No. 5 (www.ite.org), pp. 29-39.
Greenroads (www.greenroads.org) is a sustainability rating system for roadway design and construction, suitable new, reconstruction and rehabilitation and bridge projects. It is a collection of sustainability best practices, called credits. Achieving credits earns points toward an overall project score that indicates the roadway’s sustainability.
Paul Michael Grimley (2006), Indicators of Sustainable Development in Civil Aviation, Dissertation, Loughborough University (http://dspace.lboro.ac.uk/dspace/handle/2134/2755).
GTZ (Deutsche Gesellschaft für Technische Zusammenarbeit) (www.gtz.de) is a German government sponsored organization that provides international services to improve the living conditions of people in developing and transition countries.
GTZ (2003), Sustainable Transportation: A Sourcebook for Policy-Makers in Developing Countries, (www.sutp.org), by the Sustainable Urban Transport Project – Asia (www.sutp-asia.org) and Deutsche Gesellschaft fur Technische Zusammenarbeit (www.gtz.de). Many of these documents are now available in various languages including Spanish, French, Chinese, Indonesian, Romanian, Thai and Vietnamese.
Henrik Gudmundsson (2003), “Making Concepts Matter: Sustainable Mobility And Indicator Systems In Transport Policy” International Social Science Journal (www.blackwell-synergy.com/rd.asp?code=issj&goto=journal), Vol. 55, No. 2, Issue 176, June, pp. 199-217.
Ralph Hall (2006), Understanding and Applying the Concept of Sustainable Development to Transportation Planning and Decision-Making in the U.S., PhD Dissertation, Massachusetts Institute of Technology (http://esd.mit.edu/students/esdphd/dissertations/hall_ralph.pdf).
Daniel Hardy (2011), “Sustainability 101: A Primer for ITE Members,” ITE Journal (www.ite.org/itejournal), Vol. 81, No. 4, April, pp. 28-34; summary at www.ite.org/membersonly/itejournal/pdf/2011/JB11DA28.pdf.
HDR (2012), Sustainable Return on Investment (SROI) Model, HDR Decision Economics (www.hdrinc.com); at www.transpotohealthlink.com/sustainable-return-on-investment.html.
Theunis F. P. Henning, Sugandree Muruvan, Wanhua A. Feng and Roger C.Dunn (2011), “The Development Of A Benchmarking Tool For Monitoring Progress Towards Sustainable Transportation In New Zealand,” Transport Policy, Vol. 18, pp. 480–488 (www.sciencedirect.com/science/article/pii/S0967070X10001368).
ICLEI (2009), Sustainable Planning Toolkit, International Council for Local Environmental Initiatives (www.icleiusa.org); at www.icleiusa.org/action-center/planning/sustainability-planning-toolkit.
Institute for Transportation And Development Policy (www.itdp.org) is an organization that supports sustainable transportation policies throughout the world, including in developing countries.
International Council for Local Environmental Initiatives () provides tools to help communities become healthier and more environmentally responsible.
International Society for Ecological Economics (www.isecoeco.org) is a professional organization concerned with economic analysis of ecological values.
Invest (www.sustainablehighways.org) is a web-based, collection of best practices (called criteria) designed to help transportation agencies integrate sustainability into their policies, processes and projects.
Robert Joumard and Henrik Gudmundsson (2010), Indicators Of Environmental Sustainability In Transport: An Interdisciplinary Approach To Methods, INRETS (http://hal.archives-ouvertes.fr/hal-00492823/fr); at http://cost356.inrets.fr/pub/reference/reports/Indicators_EST_May_2010.pdf.
Kaydee Kirk, et al. (2010), Framework for Measuring Sustainable Regional Development for the Twin Cities Region, Center for Urban & Regional Affairs, University of Minnesota (www.cts.umn.edu); at www.cts.umn.edu/Publications/ResearchReports/pdfdownload.pl?id=1328.
Todd Litman (1999), “Reinventing Transportation; Exploring the Paradigm Shift Needed to Reconcile Sustainability and Transportation Objectives,” Transportation Research Record 1670, Transportation Research Board (www.trb.org), pp. 8-12; at www.vtpi.org/reinvent.pdf.
Todd Litman (2004), “Mobility Management Module” (www.vtpi.org/gtz_module.pdf) of the Sustainable Transport Sourcebook, published by the Sustainable Urban Transport Project in Asia (www.sutp.org) and GTZ (www.gtz.de); at www.vtpi.org/gtz_module.pdf.
Todd Litman (2009), “Mobility as a Positional Good: Implications for Transport Policy and Planning,” Car Troubles: Critical Studies of Automobility and Auto-Mobility (Jim Conley and Arlene Tigar McLaren eds), Ashgate (www.ashgate.com); at www.vtpi.org/prestige.pdf.
Todd Litman (2007), “Developing Indicators For Comprehensive And Sustainable Transport Planning,” Transportation Research Record 2017, Transportation Research Board (www.trb.org), 2007, pp. 10-15; at www.vtpi.org/sus_tran_ind.pdf.
Todd Litman (2009), Are Vehicle Travel Reduction Targets Justified? Evaluating Mobility Management Policy Objectives Such As Targets To Reduce VMT And Increase Use Of Alternative Modes, Victoria Transport Policy Institute (www.vtpi.org); at www.vtpi.org/vmt_red.pdf.
Todd Litman (2011), Well Measured: Developing Indicators for Comprehensive and Sustainable Transport Planning, VTPI (www.vtpi.org); at www.vtpi.org/wellmeas.pdf.
Todd Litman (2011), “Adjusting Data Collection Methods: Making the Case for Policy Changes to Build Healthy Communities,” From Inspiration to Action: Implementing Projects to Support Active Living, American Association for Retired Persons (www.aarp.org) and Walkable and Livable Communities Institute (www.walklive.org), pp. 104-107; at www.walklive.org/project/implementation-guide.
Todd Litman (2012), “Sustainable Transportation Indicators for TDM Planning,” TDM Review, Association for Commuter Transportation (www.actweb.org); at https://asct.memberclicks.net/assets/tdm_review_winter_2012.pdf.
Todd Litman (2013), “The New Transportation Planning Paradigm,” ITE Journal (www.ite.org), Vo. 83, No. 6, pp. 20-28; at http://digitaleditions.sheridan.com/publication/?i=161624.
Todd Litman (2012), Toward More Comprehensive and Multi-modal Transport Evaluation, VTPI (www.vtpi.org); at www.vtpi.org/comp_evaluation.pdf; summarized in JOURNEYS, September 2013, pp. 50-58; at www.lta.gov.sg/ltaacademy/doc/13Sep050-Litman_ComprehensiveAndMultimodal.pdf.
Todd Litman (2014), “Sustainable Transportation: New Kid On The Block,” in Transportation in Canada: Transforming the Fabric of our Land, Transportation Association of Canada (TAC); at www.transportation2014.ca/admin/wp-content/uploads/TAC-Ebook_ENG5.pdf.
Todd Litman (2014), Implementing Transport Policies and Programmes: Toward Realizing 'Bali Vision Three Zeros - Zero Congestion, Zero Pollution, and Zero Accidents Towards Next Generation Transport Systems in Asia, backgrounder for the Environmentally Sustainable Transport Forum in Asia and Better Air Quality Conference (http://www.baq2014est.org ), sponsored by the United Nations Centre for Regional Development and other international organizations, held 19-21 November in Colombo, Sri Lanka (http://tinyurl.com/omzobel).
Todd Litman and David Burwell (2006), “Issues in Sustainable Transportation,” International Journal of Global Environmental Issues, Vol. 6, No. 4, pp. 331-347; at www.vtpi.org/sus_iss.pdf.
Greg Marsden, Mary Kimble, Charlotte Kelly and John Nellthorp (2007), Appraisal of Sustainability in Transport, Appraisal of Sustainability Project (www.its.leeds.ac.uk/projects/sustainability/project_outputs.htm), Institute for Transport Studies, University of Leeds (www.its.leeds.ac.uk).
Michael M'Gonigle and Justine Starke (2006), Planet U: Sustaining the World, Reinventing The University, New Society Publishing (www.newsociety.com).
National Center for Sustainable Transportation (http://ncst.ucdavis.edu), at the University of California, Davis, funded by the U.S. Department of Transportation, performs research on sustainable transportation policies and technologies.
Natural Step (www.naturalstep.org) uses a science-based, systems framework to help organizations and communities work toward sustainability. The Natural Step organizations provide a variety of resources to help implement sustainability.
Peter Newman and Jeff Kenworthy (1999), Sustainability and Cities; Overcoming Automobile Dependency, Island Press ().
ODOT (2008), The Oregon Department of Transportation Sustainability Plan, Oregon Department of Transportation (www.oregon.gov/ODOT); at www.oregon.gov/ODOT/SUS/docs/Sustain_Plan_Volume1.pdf.
OECD, Project on Environmentally Sustainable Transport, OECD (www.oecd.org/env/trans).
OECD (2003), Urban Travel and Sustainable Development: Implementing Sustainable Urban Travel Policies, OECD and ECMT (www.oecd.org/cem/urbtrav/index.htm); also see Mary Crass, Sustainable Urban Travel Policies: The Work Of The European Conference Of Ministers Of Transport, World Health Organization, Regional Office for Europe (www.who.dk/eprise/main/who/progs/hcp/UrbanHealthTopics/20020118_1).
Pembina Institute (2001), Alberta GPI Blueprint Report, Pembina Institute (www.pembina.org).
Performance Measurement Exchange (http://ops.fhwa.dot.gov/eto_tim_pse/preparedness/tim/knowledgebase), is a website supported by the U.S. Federal Highway Administration and the Transportation Research Board to promote better transportation decision-making.
Anthony Perl, Special Issue Editor (2007) “Cities, Energy, and the Post-Oil Paradigm – Special Issue” Journal of Urban Technology (www.tandf.co.uk), Vol. 14, No. 2, August 2007, pp. 3-13.
PROSPECTS (2003), Transport Strategy: A Decisionmakers Guidebook, Konsult, Institute for Transport Studies, University of Leeds (www.konsult.leeds.ac.uk); at www.konsult.leeds.ac.uk/public/level1/sec00/index.htm; originally published as, Developing Sustainable Urban Land Use and Transport Strategies: A Methodological Guidebook; at www.infra.kth.se/courses/1H1402/Litteratur/pr_del14mg.pdf.
John Pucher and Ralph Buehler (2009), “Sustainable Transport that Works: Lessons from Germany,” World Transport Policy and Practice, Vol. 15, No. 1, May, pp. 13-46 (www.eco-logica.co.uk/pdf/wtpp15.1.pdf ).
RAE (2005), Engineering for Sustainable Development: Guiding Principles, U.K. Royal Academy of Engineering, (www.raeng.org.uk).
REFIT (http://refit.bouw.tno.nl/intro.htm), which stands for REFinement and test of sustainability Indicators and Tools, is a European program to provide information on sustainable transport evaluation tools.
John Renne (2009), “Evaluating Transit-Oriented Development Using a Sustainability Framework: Lessons from Perth’s Network City,” in Planning Sustainable Communities, Sasha Tsenkova, ed. (www.ucalgary.ca/cities/Places_and_People/SUSTAINABLE%20COMMUNITIES.pdf), University of Calgary: Cities, Policy & and Planning Research Series, pp. 115-148; at www.vtpi.org/renne_tod.pdf.
Barbara Richardson (1999), “Towards A Policy On A Sustainable Transportation System, Transportation Research Record 1670, TRB (www.trb.org), pp. 27-34.
Mark Roseland (2011), Toward Sustainable Communities: Integrating Environmental, Economic, and Social Objectives, New Society Publisher (www.newsociety.com).
K. Sakamoto, H. Dalkmann and D. Palmer (2010), A Paradigm Shift Towards Sustainable Low-Carbon Transport: Financing The Vision ASAP, Transport Research Laboratory for the Institute for Transportation and Development Policy (www.itdp.org); at www.itdp.org/documents/A_Paradigm_Shift_toward_Sustainable_Transport.pdf.
Bethany Schilleman and Jim Gough (2012), “Sustainability in Your Words,” ITE Journal (www.ite.org), Vol. 82, No. 5, May, pp. 20-24; at www.ite.org/membersonly/itejournal/pdf/2012/JB12EA20.pdf.
Sustainable Low Carbon Transport (SLoCaT) (www.slocat.net) is a multi-stakeholder partnership of over 80 organizations (representing UN organizations, Multilateral and Bilateral development organizations, NGOs and Foundations, Academe and the Business Sector). SLoCaT promotes the integration on sustainable transport in global policies on sustainable development and climate change.
STAR Community Index (www.icleiusa.org/sustainability/star-community-index) is a strategic planning and performance management system that offers local governments guidance for improving community sustainability.
STI (2008), Sustainable Transportation Indicators: A Recommended Program To Define A Standard Set of Indicators For Sustainable Transportation Planning, Sustainable Transportation Indicators Subcommittee (ADD40 ), Transportation Research Board (www.trb.org); at www.vtpi.org/sustain/sti.pdf.
Sustainable City pLAn (https://performance.lacity.org/sustainability) uses a dashboard of sustainability metrics to measure the City’s progress toward the Plan’s goals.
Sustainable Communities Network (www.sustainable.org) provides tools to help citizens work together to define a community's course and make it more sustainable.
Sustainable Development Indicators Website (www.sdi.gov) provides information on various environmental and sustainable development statistics available in the U.S., much of which are provided by federal government agencies.
Sustainable Highways Self-Evaluation Tool (www.sustainablehighways.org) by the U.S. Federal Highway Administration identifies characteristics of sustainable highways and provides procedures and techniques to help organizations apply sustainability best practices to roadway projects and programs.
Sustainable Mobility Project (www.wbcsdmobility.org) by the World Business Council for Sustainable Development (WBCSD) aims to chart pathways towards Sustainable Mobility that support societal, environmental and economic objectives.
Sustainable Urban Transport Project Website (www.sutp.org), aims to help cities achieve their sustainable transport goals through the dissemination of information about international experience and targeted work with particular cities.
TELLUS - Bringing CIVITAS Onto the Road (www.tellus-cities.net)
Union projects which demonstrate that integrated urban transport policies can help reduce urban traffic problems.
Transport Toolkit (http://ledsgp.org/transport) by the Transport Working Group as part of the Low Emission Development Strategies Global Partnership helps planners and decision-makers access various information resources that can help identify the most effective tools to build and implement low emission transportation strategies.
TRB (1997), Committee for a Study on Transportation and a Sustainable Environment, Toward A Sustainable Future; Addressing the Long-Term Effects of Motor Vehicle Transportation on Climate and Ecology, National Academy Press (www.trb.org); at www.trb.org/Main/Blurbs/153301.aspx.
UNEP (2011), Towards a Green Economy: Pathways to Sustainable Development and Poverty Eradication, United Nations Environment Programme (www.unep.org); at www.unep.org/greeneconomy/Portals/88/documents/ger/GER_synthesis_en.pdf.
United Nations Centre for Human Settlements (www.unhabitat.org) provides information on sustainable urban development and transportation.
Vehicle Emission Reductions Website (www.adb.org/vehicle-emissions) by the Asia Development Bank provides a forum for developing countries to share experiences and strategies in reducing vehicle emissions.
WBCSM (2004), Mobility 2030: Meeting the Challenges to Sustainability, The Sustainable Mobility Project, World Business Council for Sustainable Mobility (www.wbcsd.org).
John Whitelegg (2008), Integrating Sustainability into Transport, Eco-logica (www.eco-logica.co.uk); at www.eco-logica.co.uk/pdf/Integrating_Sustainability_Transport.pdf.
Lloyd Wright (2009), Environmentally Sustainable Transport For Asian Cities: A Sourcebook, United Nations Centre for Regional Development (www.uncrd.org.jp); at http://unpan1.un.org/intradoc/groups/public/documents/uncrd/unpan031844.pdf.
Josias Zietsman and Tara Ramani (2011), Sustainability Performance Measures for State DOTs and Other Transportation Agencies, Project 08-74, National Cooperative Highway Research Program, Transportation Research Board (www.trb.org); at http://onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP08-74_FR.pdf.
This Encyclopedia is produced by the Victoria Transport Policy Institute to help improve understanding of Transportation Demand Management. It is an ongoing project. Please send us your comments and suggestions for improvement.
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