Investigating the drivers of regeneration development in blighted areas of District 4 of Tabriz City; using spatial modeling approaches

Introduction: Cities face many challenges of urban decay that disrupt organization, reduce efficiency, and threaten urban life.While a large part of the degraded areas contain valuable cultural, historical and economic assets such as traditional markets that are vital to the identity of the city and the population. Inefficient planning creates limited opportunities for improving living conditions and increases disaster risks. Tabriz, which is historically and commercially significant, has seen land-use changes that strain its urban structure and transport networks. District 4, a historical zone of 108 hectares, is the city’s most populated area with high density, making it crucial for regeneration efforts. This study aims to identify the key drivers that can support urban regeneration in District 4 of Tabriz.
Methodology: To conduct this study, key criteria affecting urban regeneration were first identified by reviewing past research and related literature.. These criteria were grouped into four main categories: physical, environmental, economic, and social. Each category included several sub-criteria, 18 sub-criteria overall (see Table 1). Next, to assign weights and determine the importance of each criterion and sub-criterion in the context of urban regeneration, two multi-criteria decision-making methods were used: Fuzzy Analytic Hierarchy Process (FAHP) and Fuzzy Best-Worst Method (FBWM). Both methods rely on expert judgment to assign weights. In this study, questionnaires were distributed to 30 urban planning experts to gather their input for both FAHP and FBWM methods. After assigning the weights, we combined the weighted criteria layers to create urban regeneration priority maps using both FAHP and FBWM methods. The resulting maps were then compared. Finally, by reclassifying the maps, neighborhoods were prioritized based on their level of need for urban regeneration. 
Results: The results from FAHP and FBWM showed that among the four main criteria, physical, economic, environmental, and social factors (in this order) had the highest impact on urban regeneration. However, the two methods gave different importance rankings to some of the sub-criteria. According to the FAHP results, the three most important sub-criteria were: building age, building quality, and building structure. These had weights of 0.125, 0.119, and 0.115, respectively. On the other hand, the least important sub-criteria in the FAHP method were distance from fault, soil type, and land surface temperature. The FBWM method identified the following top sub-criteria: building quality, building age, and housing price. The sub-criteria with the lowest importance in FBWM method were distance from fault, land surface temperature, and soil type. A comparison between FAHP and FBWM showed that building age and building quality were highly important in both methods, with only minor differences in their exact weights. Meanwhile, distance from fault, land surface temperature, and soil type were considered among the least important in both. The urban regeneration maps produced using FAHP and FBWM (Figure 1) revealed that the southeastern and northwestern parts of District 4 in Tabriz have the highest priority for regeneration. In contrast, the southwestern and northern areas have the lowest priority. Evaluting sub-criteria revealed that: in the southeast and northwest zones, building quality is poor, and many structures are either in need of repair or should be demolished. Additionally, these areas have many buildings over 30 years old. Regarding building structure, most buildings lack proper concrete or steel frames, which makes them more vulnerable. These conditions, along with the higher weight given to these sub-criteria, explain why these areas were marked as high-priority zones in both FAHP and FBWM maps. On the other hand, areas in the southwest and north of the study area showed better conditions in terms of building quality, age, and structural type. Therefore, they were given lower priority for urban regeneration. Finally, a comparison based on the Relative Performance Curve showed that the FBWM method performed slightly better than the FAHP method, with an area under the curve of 0.874 compared to 0.845 for FAHP. 
Discussion: In this study, using FAHP and FBWM methods, neighborhoods in Tabriz Region 4 were analyzed and ranked based on their priority for urban regeneration.. The results consistently highlighted five neighborhoods, Qarah Aghaj, Ghonqa, Gajil, Ahrab, and Yekeh Tukan, as having the highest need for intervention under both models. These areas are characterized by aging buildings, high population density, and poor construction quality, all of which contribute to their elevated priority for regeneration. Qarah Aghaj, in particular, stands out due to its historical significance and numerous heritage buildings, especially from the Qajar era. This cultural value, combined with structural, economic, social, and environmental challenges, makes it a clear candidate for urban regeneration. Similarly, Ghonqa, Gajil, Ahrab, and Yekeh Tukan face comparable conditions and are thus ranked as high-priority areas. On the other hand, neighborhoods like Karpisheh, Azarbaijan Square, Jahad Square, Vazir Abad, and Kooy-e Firooz showed better overall conditions, such as higher-quality buildings, lower construction density, and improved environmental and social settings. As a result, these areas are considered low-priority for immediate regeneration efforts. Interestingly, both FAHP and FBWM approaches agreed on the top and bottom five neighborhoods in terms of priority. The main differences between the two methods appeared in the middle-ranked neighborhoods, where their scores and rankings diverged somewhat.
Conclusion: The results of this study indicate that physical, economic, environmental, and social factors, in that order, play the most significant roles in determining urban regeneration priorities in the study area. This confirms that urban regeneration is a complex, multidimensional process requiring an integrated approach. Among the sub-criteria, building age, building quality, and building structure were identified as the most critical according to FAHP, while building quality, building age, and housing price ranked highest in the FBWM model. This overlap emphasizes the consistent importance of building condition across different evaluation methods. These findings suggest that aging buildings, particularly in historically significant areas, should receive special attention from urban planners and policymakers. Poor-quality buildings not only reduce residents' quality of life but also negatively affect the overall urban fabric. Therefore, regeneration policies should prioritize enhancing construction quality through durable materials, sound engineering practices, and modern technologies. Moreover, the impact of housing prices in regeneration efforts should not be overlooked. To prevent displacement of low-income residents and the growth of informal settlements, urban regeneration strategies should carefully balance quality-of-life improvements with affordable housing considerations.