The role of planning in street evolution in Mersin, Türkiye

Streets are among the most intensively used forms of urban public space and play a central role in everyday urban life. Their publicness is shaped by factors such as morphology, accessibility, permeability, safety, land use and building–street relationships. While urban planning seeks to support collective urban life, some planning approaches may weaken street publicness by prioritizing vehicular movement, inward-oriented development and fragmented urban form. This study examines the transformation of street publicness in Mersin, Türkiye, through a comparative analysis of urban areas developed during different planning periods. Using archival research, plan analysis, satellite imagery and field observations, the study investigates how planning decisions altered the building–parcel–street relationship and reshaped the role of streets within the urban environment. The analysis focuses on street width, setback distances, building height, parcel structure, block morphology and land-use patterns. Findings reveal a gradual shift from street-oriented urban environments towards block-based and increasingly gated development models that weaken pedestrian continuity and reduce the social role of streets. The study proposes planning and design strategies to strengthen street publicness and highlights the importance of streets as multifunctional public spaces within sustainable urban development.