Climate-induced flooding and coastal transportation vulnerability: Implications for urban resilience in Izmir, Türkiye

Climate-related sea-level rise and storm surges are progressively impacting coastal cities and their transportation infrastructure, placing increasing strain on mobility in these areas. Since major transportation routes are often located in low-lying coastal areas, assessing their susceptibility to flood-related hazards has become a critical aspect of urban resilience and climate adaptation planning. This research examines the relationship between sea level variability and traffic performance under flood-prone conditions through a case study of a coastal transportation corridor in Izmir, Türkiye. The analytical framework integrates long-term relative sea level observations (1999–2024) with high-frequency traffic volume data collected during rainfall and flood-prone periods in 2023. Long-term sea level variability and seasonal patterns were examined using time-series analysis, while the empirical relationship between sea level variability and traffic flow was analysed using regression and correlation analyses. In addition, exploratory future scenarios were developed to illustrate potential exposure pathways under continued sea level rise. The findings indicate that higher sea level values are associated with modest but statistically significant reductions in traffic volumes along coastal routes. The strength of these associations varies spatially and temporally, with stronger relationships observed at specific locations and during peak traffic periods. The analysis further highlights the vulnerability of coastal transport corridors to flood-induced disruptions and illustrates how corridor-scale analyses can identify localized vulnerabilities that may be masked at broader regional scales. By linking observed traffic responses to sea level variability under flood-prone conditions, the study contributes empirical evidence to the growing literature on climate-resilient transportation systems. These insights provide valuable insights for assessing transportation vulnerability and resilience in urban growth, infrastructure management, and climate adaptation interventions in coastal cities.