Study of the Relationships between the Components of the Urban Transportation System Evaluation Model Based on Sustainable Development Indicators (Case Study: Tehran Metropolitan Area)

Introduction One of the important issues that can determine the status of a city and make changes in the quality indicators of its space is the urban transportation system. Roads and transportation systems are important elements in every city that shape the overall structure of the city. Today, with the ever-increasing population growth and development caused by cars, transportation and traffic is one of the problems of cities, especially in metropolitan areas that consist of a mother city and several satellite cities and towns, this problem is greater, because a significant population They live in satellite cities and because of their employment in the mother city, they travel to it every day, and in the absence of a reliable and planned transportation system, they increase the problems of the mother city. As long as city and metropolitan area programs and transportation system plans are prepared with the car-oriented approach, it will not be possible to achieve a sustainable transportation system. Therefore, a system for evaluating the urban transportation system based on the principles of sustainability and sustainable development implies the improvement of economic, social, and environmental indicators of cities. The present study was carried out as a part of more comprehensive research to provide an evaluation model of the urban transportation system based on sustainable development indicators in the metropolitan area of Tehran, and it seeks to examine the independence or dependency of the components of the model.
Materials and MethodsThe current research can be considered applied-developmental in terms of its purpose, and in terms of the method and period of data collection, it can be considered survey-cross-sectional research that was conducted with a mixed approach. For this purpose, in the qualitative section, by searching the databases, 43 articles were identified in related fields between 2000 and 2023, and finally, 41 articles were selected in a targeted way and entered the analysis stage. To identify the relationships between the components of the evaluation model of the urban transportation system in the metropolitan area of Tehran based on sustainable development indicators, structural-interpretive modeling was used. The participants of this section were 28 experts in the fields of urban planning, transportation, economy, social sciences, and environment active in Tehran municipality, who were selected in a non-probability, purposeful way and with a snowball pattern. In the next step, the validation of the designed model was done with the method of structural equation modeling and the partial least squares technique. The statistical population of the quantitative part includes specialists in the aforementioned fields who work in the metropolitan area of Tehran, and the sample size is 530 people. Library studies and questionnaires were considered as data collection tools, which were validated using construct validity, convergent validity, and divergent validity methods. Validation was performed in the qualitative section using the CASP model. The reviewed articles in the qualitative section were evaluated based on the ten criteria of this model and the articles with a score above 25 were selected. The validity of the questionnaire was measured through content validity (opinions from experts) and its validity was confirmed. Also, in a preliminary study, the total Cronbach’s alpha of the questionnaire was calculated as 0.856. After distributing the questionnaire to the selected sample, the validity of the questionnaire was checked using three methods construct validity (external model), convergent validity (AVE), and divergent validity. is greater than 0.5. Composite reliability (CR) and Cronbach’s alpha coefficient of each factor were determined to calculate reliability. The combined reliability and Cronbach’s alpha of all dimensions of the model should be greater than 0.7. Meta-composite analysis was used to identify the underlying categories of the research and provide the initial model. Validation of the designed model was done by the partial least squares method. Data analysis of the qualitative phase of the research was done with Maxqda software and related to the quantitative phase with Smart PLS software.
FindingsFrom the review and analysis of the articles, several 166 indicators were obtained, then the indicators that had the same meaning or were repeated in different forms and expressions were removed, and finally, with the category and classification of the final indicators, 9 components (main category) and 53 indicators (subcategory) were obtained. The findings of the research showed that the components of the model are not independent of each other and the components of pollutant production, consumption resources, energy consumption, justice and access, direct and indirect costs in the sector of independent structures, and the components of economic well-being, travel safety, health and human health, environmental compatibility are in the dependent structures section and the relationship is such that the set of direct and indirect costs and justice and access affect energy consumption. Consuming sources and production of pollutants interact and lead to environmental compatibility. Finally, economic prosperity can be achieved through travel health and safety. Also, in the model validation section, the GOF index was obtained as 0.616, which is greater than 0.36. The RMS_theta index was 0.102, which is less than 0.12. The SRMR index was also calculated as 0.050, which is less than 0.08, so the fit of the model is favorable.
ConclusionThe results of the research showed that direct and indirect costs and justice and access affect energy consumption. In the results of Hirai and Kamim’s study (2022), the effectiveness of the justice component is also mentioned, and from this point of view, it is consistent with the results of the present study. The comprehensive view is important because it defines the boundaries in which all the departments should work collectively. This perspective also calls for greater attention to quality of life and includes equity analysis to include the distributive effects of transportation between regions and countries over time. On the other hand, the transportation-oriented perspective is also important because of considers the specific goals of the sector that guide the development of transportation policies and programs. In addition, it should be acknowledged that some decisions will be made with a more appropriate and relevant transportation perspective.It was also shown that the consumption of resources and pollutant production have mutual effects and lead to environmental compatibility. In the results of the studies of Patterson et al. (2021) and Mohammadpour et al. Some of the key environmental outputs (or pollutants and waste) include hazardous waste from vehicle scrapping, noise emissions, local air pollution, and climate change. Although significant progress has been made in the proportion of recyclable vehicle waste at the end of a vehicle’s life, it is estimated that about 25% of a vehicle remains unrecyclable, and much of this can be considered hazardous. Also, noise pollution caused by traffic can disrupt sleep patterns, affect cognitive function, and aggravate some cardiovascular problems. Since noise pollution is related to the number of ongoing activities and the noise intensity of those activities, it is not surprising that it is mainly an urban problem.Finally, the results of the research showed that it is possible to achieve economic well-being through travel health and safety. This importance has been confirmed in the results of Marzi et al.’s study (1401). In addition to significant economic benefits, the transportation system also creates economic costs. Road traffic accidents and air quality both lead to loss of life or decrease in quality of life, which has direct costs for the economy in terms of lost productivity and less well-being of citizens. Also, providing the transportation system and subsidies for passengers has costs for the government that must be financed through taxes or fare collection. Therefore, the implementation of the model presented in the current research, by reducing the marginal costs, helps to increase the economic well-being of the country.