Investigating Sustainability Indicators for Urban Road Network — A Methodical Review Literature

Transportation that is both socially and environmentally responsible is an important factor in climate change. However, urban sustainable mobility schemes have no universally accepted success criteria. Sustainability evaluation lacks a common language. This document groups sustainable mobility strategies to establish critical transport performance measures. Sustainable transportation trumps targets, criteria, and indicators. The following are the top priorities for urban multimodal sustainable transportation, in descending order: There are 13 social, 11 economic, and 9 environmental criteria. Each of the three basic criteria used most often in the study specifically addresses the environment. Since the literature’s attribution of criteria to sustainability elements is complex, it’s recommended to analyze their interrelationships. As previously demonstrated, small and medium-sized cities have a high sustainability value of in terms of population and urban area, but large cities can improve their sustainability by controlling urban sprawl and managing urban transportation demand with adequate public transportation. It is proposed that in the future, the interrelationships between the criteria be evaluated, as their allocation to the aspects of sustainability is ambiguous in the available literature. This article can assist mobility executives in making decisions about urban transportation concepts and project management. Making transportation more environmentally friendly is crucial to reducing climate change’s negative impacts.


Introduction
Understanding urban processes is a crucial first step in advancing our cities' transition to a resilient and sustainable future.[1].Because cities are essentially composite systems, assessing and measuring their components is critical for making effective decisions.
One of these subsystems is urban transportation, which is essential for transporting products and people inside cities and between cities.As a result, the question of whether the city's transportation system is sustainable arises [2], although the city is not.It is feasible for a city to develop in a sustainable way when 1232 (2023) 012047 IOP Publishing doi:10.1088/1755-1315/1232/1/012047 2 its transportation infrastructure is developing.
However, according to the 2014 Revision of World Urbanization Prospects (UN, 2014), cities house 54% of the world's population, with that figure expected to rise to 66% by 2050.As a result, as more people utilize these systems daily, the demand for urban transportation networks grows gradually, becoming a primary driver of sustainable cities.Most cities have traffic congestion and air pollution as a result of individual motorized transportation modes, and a major portion of the population spends hours traveling to their destinations owing to persistent congestion [3].However, there is an international agreement that technology opportunities for reducing GHG emissions are insufficient to reduce these emissions efficiently, hence behavioral adjustments on both the individual and decision-making levels are required.evaluated the implications of Wien's downtown redevelopment, in which the majority of the roads were transformed into streets, producing one of Europe's more comfortable and lively urban architectures.Presently, two-thirds arrive by public transportation, cycling, or walking, illustrating the importance of making strategic decisions regarding urban transportation networks to improve urban sustainability.According to Alonso et al. (2015), in metropolitan regions where pollutants and their consequencescaused by unsustainable transportation structuresare concentrated, Sustainable transportation is a requirement for creating sustainable cities. backed up these claims, identifying technological progress and reduced demand as appropriate and efficient ways for building a sustainable transportation system.The European Union's White Paper on Transport outlines the essential needs for attaining sustainable urban mobility, such as pedestrian-and cycling-oriented infrastructure, a decreased number of automobiles with internal combustion engines, and the promotion of public transit.
Although certain relationships between transportation operations and environmental degradation remain ambiguous, the key pillars of sustainability and their convoluted interactions may be identified.The steadily rising number of evaluations of the transportation industry in terms of sustainability [4] demonstrates the topic's importance and relevance not only on a global scale but also in Hungary.The primary goal of these previous studies was to examine sets of urban sustainability transportation indicators developed for measuring urban transportation sustainability.
An assessment and evaluation to implement sustainable transportation is being done to assess the practicability and feasibility of urban multi-modal transport projects over a lengthy period in a way that is both focused and general.This work broadens the scope of earlier evaluations by defining measuring elements as well as a unique standardization of components into a unified measuring hierarchy.In addition to this, the work contributes to the development of a suitable measurement hierarchy.Goals and an indicator for visualizing urban sustainable transportation schemes are the main criteria.This systematic study will aid urban multifunctional sustainable transportation project planners and implementers.The study concludes with a discussion of job issues and research directions.

Sustainability of the Transportation
Before explaining what is needed for sustainable transportation, it is important to know what "sustainable transportation" and "sustainability" mean.The Brundtland study defines sustainability as: Sustainability protects future human life [5].This term's inapplicability necessitated more meanings.Most split it into economic, social, and environmental components.Social stability, financial sustainability, and environmental accountability overlap (social-environmental) [6].Sustainability is defined as the integration of all of the described elements, and none of the three components may take precedence.Although some writers argue that the environmental aspect involves planetary boundaries, the most important finding of this study is that sustainability is viewed as a fair equilibrium of criteria encompassing socioeconomic issues, the environment, as well as the.economy.There is no commonly agreed-upon concept of sustainable transportation.Nonetheless, most definitions continue to incorporate and emphasize social, environmental, and economic goals [7].Banister created the most well-known concept to improve the operational feasibility of sustainable transportation.The following are the elements of his concept, which are supplemented by announcements from other important authors: • Modal shift, which reduces car travel and promotes more environmentally friendly modes like bicycles and public transit.Upgrading cycling and pedestrian amenities, promoting multimodality, limiting car parking, and raising road taxes promote shifting.Thus, other mobility metrics often cause it.• Fewer trips and shorter distances.Urban design affects traffic reduction.
• Transportation economy.Sharing and low-emission vehicles enhance.
• Digitalization, such as smart applications or transportation like a solution provider that provides many intermodal and multimodal passenger transport options, aids in the transition away from vehicle use [8].

Sustainable transportation definition
The first step in investigating the key issues, bottlenecks, and intervention areas in the urban transportation sector is to define the sustainable urban transportation concept.As stated, it is critical to clearly define which components require attention given the connection between urban areas, transportation, and sustainability.As a more limited understanding of sustainable transportation, the emphasis is on transportation sustainability in general or specifics in urban areas.Because there is no scientific agreement on a precise definition of a sustainable transportation system, a more comprehensive collection of available definitions and attributes is a critical component of the solution.Because conceptualization is not the goal of this study, the collection of definitions serves no function in creating a coherent idea, but it is unquestionably beneficial in comprehending the many methodologies and indicators utilized in diverse investigations.cited the European Council of Ministers of Transport's definition of transport sustainability, which describes the concept as having the following characteristics: x From a social standpoint, a sustainable transportation system provides basic accessibility for individuals, businesses, and society, as well as connecting present and future generations; x On the economic side, it makes the area more competitive and helps it grow by running quickly and cheaply.x Lastly, from an environmental point of view, it encourages the use of renewable resources and the limitation of emissions and waste based on the planet's ability to absorb them.This can help prevent future negative effects.Nevertheless, stressed accessibility as the most important aspect of sustainable transport and did not offer solutions for the economic and environmental dimensions of sustainability.Yet, the majority of studies on sustainable transportation focus on the environmental implications of motorized modes of transportation.Therefore, it is clear that sustainable development only considers environmental implications.[2].This limitation was cited by, Someone mentioned that some of the indicators and concepts proposed in many studies reflect and monitor environmental factors, and therefore, decision-making procedures produce ecologically effective but economically inefficient solutions.On the flip side, some economic factors may result in environmentally ineffective policies.According to Zito and Salvo (2011), the following factors are required for achieving sustainable mobility: a reduction in the demand for transportation, the facilitation of a modal shift, a reduction in journey length, and incentives for greater efficiency.To avoid singular and rare meanings, the most inclusive definition of sustainable transport may be accepted as "satisfying current transportation and mobility needs without compromising the ability of future generations to meet their own needs."[9].This notion is a slight modification of the Brundtland Commission's 1987 definition of sustainable development.This idea allows us to consider the fundamental elements of sustainable transportation, including economic, environmental, social, and institutional components.This study agrees with this method and uses it to look at a set of urban indicators and the suggestions that come from that.

Measuring and evaluating sustainable development
Before measuring any concept, such as sustainability or environmental sustainability, an operational definition must be developed.A functional definition must indicate how a concept will be measured.[10].For instance, a practical implication for achieving fine particle matter air quality standards (PM2.5)is: "Areas will comply with the annual PM2.5 standard when the 3-year average of the annual arithmetic mean PM2.5 concentrations is less than or equal to 15 g/m3."In this instance, the operational definition specifies how the concept of air quality compliance (for fine particles) will be measured.Satisfaction with air quality requirements is shown by mean PM2.5 values.
The Brundtland Report's definition of sustainable development is probably the most frequently cited: "to ensure that [development] meets the needs of the present without jeopardizing future generations' ability to meet their own needs."Rather than an operational definition of sustainability, the Brundtland definition offers more of a general statement of principles.The economists' viewpoint provides one tractable technique for arriving at an "operational definition" of the idea of sustainability.Use the economist's perspective of sustaining the value of total capital, encompassing human, natural, social, and manufactured capital, if it implies defining sustainability as the ability to "keep the capacity to deliver non-declining wellbeing across time".By the mid-1990s, the World Bank had previously said that it would only fund "economically, environmentally, and socially sustainable" projects (Serageldin, 1996, p. 2 [emphasis in original]).And, ostensibly, he characterized sustainable development as a process wherein current generations transfer as much or more capital per capita to future generations, where capital is described as human-made, environmental, social, and human resources.This definitional approach greatly suffers from measuring challenges, including, but not limited to, issues of how to assess the "stock" of social capital.Additionally, there are two opposing, non-falsifiable perspectives about capital substitutability: "weak" sustainability (natural capital can be replaced by other kinds of capital) and "strong" sustainability (natural capital cannot be replaced by other types of capital) [11].

Evaluate studies
Table 1 gives a summary of each previous study, including criteria for sustainability, how to use criteria, and how to choose indicators.Nearly all studies utilized particular criteria to evaluate the viability of various transportation projects.Globally, application areas range from Europe to the Americas and Asia.The majority of these studies concentrated on urban projects.Only Bojkovic et al. [11] addressed the sustainability of global transportation networks.The majority of publications (81%) explored the environmental, social, and economic components of sustainability.Noticed that the language is slightly different in the papers.Castillo and Pitfield [12], for example, refer to the social dimension as " social inclusion and equity."More than half of the responders (52%) contributed one or even more new dimensions, including technology, efficacy, or efficiency.Only Gössling [13] included walking in his assessment of sustainability.Only two publications, along with Castillo and Pitfield [12], were about cycling, which is noteworthy because those are thought to be lively and thus healthy modes of transportation.[14].A literature review was the most commonly utilized method of data collection, appearing in 95% of all studies.For clarification, several authors included expert interviews.Most authors assessed transportation alternatives using criteria.Only one publication has used criteria to develop a comprehensive definition of sustainable transportation.  1 and the section on evaluating studies, the papers' hierarchical levels and terms differed.Due to the literature's varied terminology and hierarchical levels, these differences exist.Thus, the following unifies the literature's levels of hierarchy and sublevels and their definitions: x Society, economy, and environment are all components of sustainability, according to the 2030 Agenda for Sustainable Development.In addition to a few others, most of the authors in the reviewed literature used the terms dimension [ [11], [29], [30]] or category [ [15], [16], [27]] for social, economic, and environmental issues.
x Related or similar subjects are grouped into several classes [ [28]], which are referred to in the evaluated publications as themes [ [11], [31], [29]] or enablers [ [25]] and occur along measurements. x The variance between an aim and a goal is that a goal implies a direction (to increase or minimize).In the literature, this phrase is not defined at all.x According to Litman [47], the sustainability goals should be higher in the hierarchy than the objectives.Both of these serve as guidelines for choosing indicators.while the purpose is the complete goal to be evaluated, which is sustainable transportation.x Criteria and attributes are utilized interchangeably and represent a performance indicator for the goal that they operationalize and characterize [48].To be able to describe the aims they represent, they must be measurable, intelligible, and operational.As a result, criteria must not be ambiguous; that is, each level of success indicated by a criterion must have a meaning, Criteria may also be qualitative ways of expressing goals, [47].
The indicators are used as a scale to measure how much a project contributes to each of the goals.Measurability is required for indicators.This is the most straightforward term in the literature.

Categorizing criteria
The criteria for linked topics were compiled, and the most significant criteria were presented as phrases.
To accomplish this, the criteria that had more than one meaning were split up.This is what happened with the noise and vibration criteria.[27], safety and well-being [32], health, security, and safety [35], and speed of service and ease of use.Because of this method, five new criteria were made.Second, the criteria of the authors who employed two or more criteria with nearly equivalent implications in the same dimension were merged.The combining of transit accidents and accident impact reduction is one example, as both criteria are associated with accidents in a larger sense.Stewart and Lord adopted the term "crash" rather than "accidents" because "crash" has a broader connotation and implies both accident and intentional or irresponsible conduct.Also, concentrations of air pollution emissions and emissions per person were taken into account.11fewer criteria were evaluated because of the use of combinations.This procedure is illustrated in Figure 1.Based on the significant of each criterion, 202 criteria need to be divided into key criteria.38 essential criteria were produced as a result of this process, serving as collective names for various elements with the same broad meaning.The most important factors and their components are outlined in the passages that follow.In some cases, particular contaminants served as the standard for air quality (e.g., PM10 or NOx).Other times, the coverage of pollutants in both land and water was too wide.Therefore, a significant criterion that's both too broad or even too limited was chosen: air pollution.The main energy consumption criterion takes into account resource utilization as well as energy expenditure, intensity, and effectiveness.The main factors affecting noise are noise pollution, noise perceptions, noise level(s), and noise decrease [35].
A connection exists between greenhouse gas production and both air pollution and climate change.Safety measures aim to limit negative effects on safety, set safety standards, reduce risk, and enhance perceived safety, among other things.Examples of criteria given through the primary criterion of health include the advantages of health, the risks to health, the seriousness of injuries, the effects of road accidents, and the effects of air pollution.The running expenses also include the costs of implementation, upkeep, and gasoline.The original expenditure is not included in these costs.The majority of time spent traveling is reported as commute time and the amount of time needed to get to the next transportation center [40].Accessibility may also be explained in terms of aging or people with disabilities.The other comparable criteria were successfully combined into the other main criteria as well [33].The principal criteria's relation to environmental aspects the main factors were then determined, and they were then assigned to the sustainability dimensions, where they were frequently cited in the literature study.Only the primary criterion of journey length was allocated to a dimension other than the one in which it was most frequently mentioned because a number of the analyzed pieces focused on freight transit (economic).Time was thus viewed by the service provider as a financial issue rather than as the length of time passengers were in the vehicle.As a result, the journey time was allocated to the social component since it better captured the overall goal of sustainable passenger transportation.This led to the elimination of frequency, customer satisfaction, substitute propulsion technologies, public transit, and social expenses.There were 33 main criteria with 197 references following this modification.In Table 5, these key factors were assigned to the three dimensions and arranged according to how frequently they occurred.The main noise measure in the literature was murky because it applied to both the social and natural aspects.Furthermore, the author claimed that travel time was both a social and an economic issue.The same may be said about cost, depending on the article's viewpoint (for the provider or the user).In conclusion, there were nine environmental criteria, eleven economic criteria, and thirteen important criteria linked to the societal component.In terms of the percentage of references (a total of 197) or the number of times each significant parameter was referenced, the social component was named the most (42%), followed by the environmental (37%), and the economic (21%).The three main criteria were most commonly cited were all connected to environmental aspects.This is in line with the idea that the other two aspects depend on the surroundings.

Sustainability Main Criteria Classification
The fundamental objective of every criterion was taken from the comprehensive literature review and suggested as an indicator to demonstrate the criteria to also be evaluated.Table 2 displays the assessment system for sustainable transportation.As noted previously, the criteria often did not appropriate into a single dimension, and approximately had many effects instantaneously.Similar to how criteria are allocated to dimensions, the relationships between criteria and their purposes might be neutral, complementary (unilateral or mutual), or hostile.As noted throughout the grouping procedure, for instance, traffic congestion is strongly correlated with travel time.GHG emissions and, by extension, CO2 emissions are closely related to air pollution, which has detrimental impacts on health.The primary criterion, "non-motorized modes," also influences these metrics.All of this is exacerbated by congestion.Furthermore, there is a relationship between energy consumption and fuel expenses.Another unclear factor is price.Price increases increase revenue for service providers but lower affordability for users.In general, advances in economic achievements frequently lead to declines in social or environmental performance.Before choosing criteria for decision analysis, it is very important to look at possible connections and, in particular, compromises.Picking a lot of criteria without taking into account how they might affect another criterion may not always lead to better decision-making.As the first step in making a composite index (OECD), the measurement elements given were made based on advice from the Organization for Economic Cooperation and Development.They serve as a theoretical cornerstone for a deeper understanding of efficient transit.The criteria must be chosen from Figure 2 and applied to a specific situation by considering, among other things, the availability of data relevant to the chosen use case and the coherence of the collection of criteria that was ultimately chosen.

Table 2. Sustainable transportation measurement
Therefore, almost all writers evaluated the viability of particular transportation initiatives using specific criteria.Most writers concentrated on urban projects.The viability of national transit networks over the long term has only been studied by Bojkovic et al. 81% of the pieces looked at sustainability's societal, environmental, and economic facets.The social component is sometimes referred to as "equity and community inclusion" by Castillo and Pitfield, for example, greater than 50% of one or more additional variables, such as technology, system efficiency, or usefulness, were mentioned by more than half (52% of respondents).In his assessment of the viability, only Gosling takes strolling into account.Castillo and Pitfield were two of the only papers that talked about cycling.This is important because cycling and walking are seen as healthy ways to get around.In 95% of all studies, the main way that information was gathered was through a review of the literature.Several authors included expert interviews for an explanation.The majority of authors used standards to evaluate the sustainability of various transit options.Only one book used standards to give a comprehensive explanation of what constitutes sustainable transportation.

Discussion
A follow-up study that uses the resulting set of criteria to assess the environmental effects of various metropolitan transit options may build on the conclusions of this systematic literature review.In a multicriteria decision analysis, for instance, the criterion might be applied to determine which of several possible metropolitan transit options is the most environmentally friendly.There is a wide selection of such analytical tools and methodologies that may be obtained and have been used in the past.On the other hand, the criteria that were given in this work have not been combined for such an evaluation as of yet, which demonstrates the need for more research.When doing a multicriteria analysis, it is common practice to give the various criteria varying degrees of importance (e.g., to express priorities).One other question that has to be answered by future research is how to best assign weights to the various criteria that were discussed in this article.In addition, the availability of data as well as its trustworthiness is essential considerations for the selection of criteria while carrying out multicriteria analysis.Because the availability of data might be different in different places due to differences in geography, the criteria for choosing from this set can be changed to fit the needs of a particular research project.

Conclusions
x Because most criteria are not assigned to only one sustainability dimension in the existing literature, future works on the subject should pay particular attention to the tradeoffs between the criteria.x The discovery of tradeoffs between criteria is a very important topic for future research.Theories and the practical implications of these discoveries deserve special attention.x While it comes to sustainability, competing agendas are another key aspect to consider when delivering new solutions for transportation inside business ecosystems, including a variety of partners from a wide range of companies.weight that different actors put on certain sustainability criteria may vary.x Another subject worthy of inquiry is the identification of such disputes and how they may be resolved.To sum up, transportation is one of the most important factors in reducing the negative effects of climate change.
x Making transportation better for the environment is the most important thing that can be done.
This evaluation sets the stage for much-needed future studies into how to create urban transportation investments that are socially acceptable, good for the environment, and profitable.

Figure 1 .
Figure1.The chosen paper in terms of the criteria[49] passenger-km to respective energy consumption(max) Noise pollution impacts(min) Noise Noise pollution [dB levels) Climate change due to GHG Emission tensity of GHG [CO2 eq/pkm]

Table 1 .
Final sustainable transportation indicator in previous studies.