Assessing Infrastructure Accessibility as a Prerequisite for Decarbonized Mobility: A Case Study of a Coastal Port City

Sustainable transport transformation increasingly depends on the configuration and performance of urban infrastructure systems. In coastal and port cities, decarbonizing transport is particularly complex due to spatial constraints, heritage protection requirements, and the coexistence of freight and passenger flows. In such environments, accessibility functions as a key indicator of transport infrastructure performance, reflecting how effectively transport systems enable low-carbon and multimodal mobility choices. Gdynia, a major Baltic port city in Poland, represents a context in which infrastructure limitations intersect with growing mobility demand. The concentration of port-related traffic, compact urban form, and limited opportunities for network expansion create structural conditions that may reinforce car dependency. This study examines infrastructure and accessibility challenges at the micro-scale of the Faculty of Navigation at Gdynia Maritime University, a centrally located campus with limited integration into public and active transport systems. Based on a survey of 342 respondents, including students and employees, the research analyzes modal split, travel time, and perceived barriers to sustainable mobility. The findings reveal infrastructure gaps in public transport connectivity, cycling network integration, and parking policy, collectively influencing transport behavior and constraining the shift toward low-carbon mobility. The study highlights the importance of infrastructure alignment, intermodal integration, and accessibility-based planning as prerequisites for smart and sustainable transport systems in coastal areas.