A composite index for assessing accessibility in urban areas: A case study in Central Athens, Greece

Effective transportation planning necessitates the consideration of all road network users and their needs. To-wards this goal, the integration of accessibility in planning and the development of tools that enable the assessment and measurement of accessibility within urban areas becomes essential. This study aims to contribute to the accessibility assessment process of urban areas by developing two accessibility indices: the infrastructure and the opportunity accessibility index, which use an infrastructure-based and distance-based approach, respectively. Four types of users and their needs are considered: pedestrians, People with Disabilities (PWD), cyclists and public transport users. Data for modeling the accessibility indices are collected by: 1) an infra-structure audit, 2) a user survey, and 3) geographic information systems. The proposed method is applied in a district in central Athens, Greece, which is characterized by high population density and high level of activities. The Infrastructure Accessibility Index (IAI) measures accessibility for sidewalks, crosswalks, bikeways and public transport stops. The IAI results indicate moderate accessibility levels for pedestrians and PWD, for sidewalks and crosswalks. The Opportunity Accessibility Index (OAI) measures the share of different types of users that reach different opportunities within a time threshold. The accepted time threshold per user type is estimated based on the survey responds, for seven different opportunities: green spaces, recreational spaces, education buildings, health buildings, public service building, commercial uses and public transport stops. Compared to the IAI, the majority of users reach different opportunities within the estimated time threshold. The study concludes with recommendations to improve accessibility levels at local level.