Network accessibility as the emergence of cliques

Šfiligoj, Tina (author), Peperko, Aljoša (author), Cats, Oded (author)

We propose a topological formulation of accessibility based on the notion of Access Graph, in which two nodes are connected if they are reachable within a given travel time. We trace the emergence and evolution of its subgraphs with imposed levels of connectedness, specifically maximal clique and k-cores. We propose two complementary sets of accessibility indicators, cumulative and threshold, based on integral measures of subgraph growth and times at emergence of k-cores, respectively. For a meaningful comparison of networks across different dimensions, we contrast the realised accessibility with that of an idealised network on the same set of nodes. The proposed measures offer a view of accessibility that extends beyond the commonly used node-averaged indicators. Empirical analysis of 42 metro networks worldwide demonstrates universal patterns of accessibility behaviour. We illustrate the practical application of this approach on a case study where we examine the accessibility impacts yielded by alternative infrastructure and service developments. Our results amount to the reconceptualisation of accessibility within the complex network framework.

• Language: English
• Keywords: public transport, accessibility, network science, transport network
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FPP - Faculty of Maritime Studies and Transport; FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: Str. 1-27
• Numbering: Vol. 16, art. 5089
• PID: 20.500.12556/RUL-182819
• UDC: 004.7:656.025.2
• ISSN on article: 2045-2322
• DOI: 10.1038/s41598-026-35542-1
• COBISS.SI-ID: 266608131
• Publication date in RUL: 25.05.2026

Record is a part of a journal

• Title: Scientific reports
• Shortened title: Sci. rep.
• Publisher: Nature Publishing Group
• ISSN: 2045-2322
• COBISS.SI-ID: 18727432

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: javni potniški promet, teorija omrežij, prometno omrežje