Citation: Emmanouilidis, S.; Basbas, S.; Sdoukopoulos, A.; Politis, I. Settlements along Main Road Axes: Blessing or Curse? Evaluating the Barrier Effect in a Small Greek Settlement. Land 2022, 11, 2243. https://doi.org/10.3390/ land11122243 Academic Editor: Xuesong Kong Received: 22 October 2022 Accepted: 6 December 2022 Published: 9 December 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). land Article Settlements along Main Road Axes: Blessing or Curse? Evaluating the Barrier Effect in a Small Greek Settlement Savvas Emmanouilidis 1 , Socrates Basbas 1, * , Alexandros Sdoukopoulos 2 and Ioannis Politis 2 1 School of Rural and Surveying Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece 2 School of Civil Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece * Correspondence: smpasmpa@auth.gr; Tel.: +30-2310996126 Abstract: Being the heart of every human settlement, the road network constitutes a significant component of the built environment that serves the accessibility and mobility needs and supports economic activities. Despite its positive role, the road network, in some cases, due to increased geometric and functional characteristics, can act as a barrier to the movement of vulnerable road users, thus fragmenting the urban space and creating the phenomenon of the “barrier effect”. The barrier effect is considered detrimental to the mobility of vulnerable users, causing delays or even cancellation of trips, increasing collision risk, limiting access to services, posing negative impacts on public health, and loosening social ties. In this context, the current paper focuses on a settlement in Greece (Dispilio) developed along two national roads and comprehensively evaluates the barrier effect. More specifically, the presented methodological approach attempts to investigate the actual and the perceived dimension of this phenomenon by applying well-established metrics and landscape indicators, such as the effective mesh size, and conducting a questionnaire survey, respectively. The overall research results highlighted interesting findings regarding the intensity of the barrier effect in the examined area and outlined some critical interventions that could be implemented in similar cases. Keywords: barrier effect; community severance; fragmentation; effective mesh size; extra travel distance; questionnaire survey; Greece 1. Introduction Traditionally, the development of human settlements along main road axes serving connections on regional and national scales was common practice in many countries. This linear type of development, applied over several decades mainly to small-sized settlements, such as towns and villages, was driven by the capacity of regional and national roads to reduce the social isolation of these communities, contribute to their economic growth and openness, and provide enhanced access to adjacent destinations, employment opportunities, education, recreation facilities and health services [1–7]. Although the presence of main road axes was a “blessing” in terms of regional accessibility, over the years, people living in such settlements started to realise that, at the same time, it is a “curse” hindering movements on the local scale [8]. More specifically, road infrastructure and motorised traffic often act as a barrier to the movement of vulnerable users such as pedestrians and bicyclists, thus fragmenting the urban space and creating the “barrier effect” [9]. This phenomenon, also known as “com- munity severance” as the two terms are typically used interchangeably [8,10–14] despite the fact that the latter often embraces a broader range of impacts on local communities [9,15,16], is the result of the presence in the built environment of various static, dynamic or psycho- logical barriers [13,17,18]. Although the elements of the built environment that could act as such vary considerably, restricted-access transport infrastructure that prevents crossing, including railways, motorways, dual carriageways, and multi-laned freeways, comprise the Land 2022, 11, 2243. https://doi.org/10.3390/land11122243 https://www.mdpi.com/journal/land