Modeling the historical relationship between waterfront development and transport infrastructure: Evidence from Jeddah’s coastal transformation

The redevelopment of waterfronts is increasingly perceived as a transport-mediated spatial process as opposed to a design or land-use process. Nevertheless, limited information exists on the impacts of transportation infrastructure on waterfront integration over time, nonlinear dynamics and temporal lag effects, particularly in rapidly urbanizing regions. This paper examines the history of the relationship between the evolution of transport infrastructure and waterfront spatial integration along the Jeddah coastline in a longitudinal, GIS-based study. The analysis combines network accessibility, pedestrian permeability, land-use intensity gradients, and a composite Waterfront Mobility Integration Index (WMII) across three historical development phases. Normalized indicator trajectories, sensitivity tests, and counterfactual situations are used to analyze the concepts of threshold behavior and time lag. It has been found that accessibility to transport grows more rapidly than other spatial dimensions, and that substantial growth in pedestrian permeability and the continuity of public space is achieved only after accessibility becomes critical, with a time lag. The findings reveal that accessibility is sufficient, though not necessary in waterfront integration, and that pedestrian infrastructure is the mediating variable in the transformation of transport investment into continuous, publicly accessible waterfront environments. The research adds to the transport-waterfront literature by offering a replicable analytical framework on evaluating waterfront change in fast growing coastal metropolitan areas and providing longitudinal evidence of threshold effects and lagged spatial response.