Assessing the fragmentation-barrier effect in urban areas: The case study of Thessaloniki, Greece

Abstract

Transport infrastructure is an integral part of every urban area serving the accessibility and mobility needs of people and goods. However, despite its significant role, transport infrastructure, due to its geometric and functional characteristics, can sometimes act as a physical or psychological barrier to the movement of vulnerable road users, thus fragmenting the urban space. The fragmentation of the built environment, or in other words, the “barrier effect”, is a problem that has attracted growing attention during the last decades as a consequence of its severe negative impacts, the entailing social and economic inequalities, and the increasing population ageing. In this context, the current paper presents a methodological approach for assessing the degree of fragmentation of urban areas. The proposed methodological approach utilises the well-established landscape fragmentation indicator “effective mesh size - meff” and attempts to adapt it to the urban environment. Moreover, it presents a slight modification in its structure, thus leading to values ranging from 0 to 1, to facilitate comparative analyses between different areas and favour the easier interpretation of the results. In order to highlight any issues of usability and credibility, the methodological approach presented in the paper was also applied to the seven municipalities that comprise the Metropolitan Area of Thessaloniki. The pilot implementation underlined significant differences between the aforementioned cases and highlighted the value and reliability of the methodological approach.