An Analysis of the Future of Public Transport Systems in the Framework of Environmental Sustainability the Case Study of Tehran Metropolitan

A B S T R A C T
As previous studies have shown, despite the breadth and variety of criteria explaining sustainability, the factors affecting its realization are generally neglected and especially in the field of public transportation systems and future studies, there are theoretical gaps. Therefore, in the present study, the future of the public transportation system of Tehran metropolis was explained and modeled as a study sample for the year 2031. The data used included environmental survey variables and interviews with experts. To analyze the data, the structural analysis method based on Micmac software and the scenario analysis method with Scenario Wizard software were used. The results showed that the public transportation system of Tehran metropolis is a very vulnerable and fragile system and due to the high interaction of the system factors, with the smallest change in the key drivers, other variables of the system also undergo serious changes and make it more and more distant from the stability components. they say Based on the identification of eight key drivers and three predetermined factors, a total of 11 scenarios were identified, including two improbable scenarios, three incompatible scenarios, one scenario with a weak probability of occurrence, two scenarios with a medium probability of occurrence, and three scenarios with a strong probability of occurrence. Finally, it was concluded that in the next 10 years, Tehran will face a more individualistic and aging social structure, a fragile environmental structure with high pollution and possibly an unstable economic structure. Such a city needs a type of public transportation system that can meet the demands of all groups and citizens at a low cost and is accessible with inclusive features
Extended Abstract
Introduction
Regardless of the sociological factors and the social and behavioural contexts encouraging the use of private cars in Tehran, it seems that the lack of a vision based on the future and as a result, the lack of a coherent and efficient plan to guide and improve the public transportation system of the metropolis of Tehran towards the element of sustainability, Among the inefficiencies of the management and policy-making system of Tehran city. The lack of a future-based perspective has caused transformational measures to be implemented in the city's public transportation system in a phased manner, and with the change of management periods, including the change of mayors and Islamic councils, these policies have also been changed or forgotten. It can be said that the planning and policy-making system of urban development in the country's metropolises, including in the metropolis of Tehran, not only has not considered the future-based approach in its planning, including in the field of transportation but its planning is based on the traditional idea of "know, analyze, plan". which is based on recognizing the problems of the current situation of a phenomenon and presenting a plan and program based on the same problems of the current situation. This method is now obsolete.
Based on all the topics raised, the current research seeks to answer the following two questions:
1) "Sustainability" of public transportation systems of Tehran metropolis in the future of 20 years is affected by what drivers?
2) Based on the most important drivers affecting the future of Tehran's public transportation systems, what realistic scenarios can be proposed and implemented for the next 20 years?
 
Methodology
The method used in this research is foresight based on scenario analysis. In this way, based on the most likely images and future perspectives of the system, possible scenarios for the future of the city's public transportation are presented. The data used are obtained from sources such as the theoretical literature of the subject and previous research, and interviews with experts. The interviewees included 14 specialists and university professors who are experts in the field of urban transportation. Experts were identified by a targeted snowball method. To analyze the data, the structural analysis method with the cross effects matrix technique was used in Mic Mac software and the scenario analysis method was used in Scenario Wizard software. Simultaneously with this questionnaire, another questionnaire was distributed to evaluate the importance and certainty of drivers in the range of 1 to 10. Based on the results of these two questionnaires, the drivers were monitored and screened and the key drivers were determined. These key drivers were evaluated in the form of several scenarios and the possible states of each driver were determined in three favourable, static and critical states. Finally, strong, compatible and probable scenarios were identified.
 
Results and discussion
Based on the results, the drivers of public transportation in Tehran include 8 influential variables, 7 effective variables, 21 two-way variables and 5 less important variables. The dispersion of the variables on the diagonal axis of the Mik-Mak diagram shows that the system in question is unstable and fragile. In such a system, due to the dominance of two-way drives that have high effectiveness and effectiveness at the same time, with the smallest change in a variable, the whole system is disrupted. As seen in Figure 4, 11 propellants had high effectiveness and 16 propellants had high effectiveness. It can be said that the future of the public transportation system of the Tehran metropolis depends on these few drivers. To what extent do Tehran's governing bodies and urban management accept environmental standards and regulate the quality of public transportation services with these standards, to what extent do they support clean energy, and on the other hand, how are their relations with transportation equipment manufacturing companies and also To what extent international sanctions can be effective will determine the future of public transportation in Tehran.
 
Conclusion
By identifying the most important drivers related to the future of Tehran's public transportation system, the present study showed that the factors and drivers affecting this system have a high interaction, which results in the creation of a fragile and vulnerable system with a high influence of political and economic developments and trends. Is. The stability of this system depends on a series of factors and trends outside the system.
Based on the obtained results, the most important driving forces shaping the future of the public transportation system in Tehran, such as the amount of budget allocation and credits to the public transportation system, how to manage travel demand, the amount of acceptance of private cars by citizens, the number of pollutant emissions, the amount of application of environmental standards, the amount Acceptance and development of new technologies, the effectiveness of international sanctions and the presence or absence of a coherent and purposeful vision in the body of urban management.
Based on the results obtained from the analysis of the future scenarios of this system, it can be said that due to the critical nature of most of the possible situations in each of the key drivers, there is no bright future for public transportation in Tehran. Because the probability of favourable scenarios is very low. In addition, in the next 10 years, Tehran will face a more individualistic and ageing social structure, a fragile environmental structure with high pollution, and possibly an unstable economic structure. Such a city needs a type of public transportation system that can meet the demands of all groups and citizens at a low cost and is accessible with the characteristic of inclusiveness and ubiquity.
 
Funding
There is no funding support.
 
Authors’ Contribution
All of the authors approved thecontent of the manuscript and agreed on all aspects of the work.
 
Conflict of Interest
Authors declared no conflict of interest.
 
Acknowledgments
We are grateful to all the scientific consultants of this paper.