Sustainable urban mobility has been the epicenter both at the scientific and administrative level during the last decades, with a high number of relevant research projects, awareness campaigns, and other initiatives taking place at the local, national, and international level. However, many urban areas have so far achieved limited results in this direction because of political, institutional, organizational, technological, infrastructural, and socio-economic barriers as well as unforeseeable (e.g., COVID-19) conditions. The overall aim of the present research study is to support policy-making by proposing a methodology that identifies and prioritizes the sustainable mobility barriers for a specific urban area, with a view to developing effective policies. Towards this purpose, this work provides, in the first phase, a comprehensive inventory of barriers based on a literature review. In the second phase, a methodology using as a basic scientific tool a modified Delphi-AHP is proposed for the adaptation of this inventory to a specific urban area and for both the evaluation and prioritization of sustainable mobility barriers. The whole process is then applied in Thessaloniki, Greece, a European city suffering from many problems related to sustainable mobility. The above pilot application confirms that this approach can be integrated as a supporting tool in the first steps of sustainable urban mobility plans (SUMPs).

Rail freight reportedly makes for an environmentally friendly means of transport. It also has significant potential for making a lucrative business, a stark contrast to rail passenger transport. Yet in Europe rail freight has long been displaced over its road equivalent and grown at rates inferior to overall land goods freight. Sustainable, profitable rail freight operations depend not only on goods volume, travel distance and pricing, but further on other key aspects permeating goods transportation by rail. Our research demonstrates that the choice for railway undertakings, infrastructure owners, and regulators alike, is in practice a complex one as depending on many, often competing factors. In fact, the key questions usually raised v.a.v. rail freight operations may be summed up to the following: (a) Mixed passenger and freight train operation or dedicated train corridors? (b) Conventional or heavy axle loads for freight trains? (c) Unitized wagonload or integrated trainload services? (d) Dangerous goods land shipping by rail or road? (e) Autonomous or manned freight train operation? Despite many individual contributions in the field, there is currently no single framework addressing the problem holistically. This paper breaks down what is seemingly a hard-to-balance decision-making process for rail freight players. It records and analyzes the forces and dynamics behind the dilemmas above and allows to: provide those partaking in the decision-making process with a robust framework identifying the key drivers behind sustainable rail freight growth; help them individually and collectively make more sound decisions regarding rail operations as a whole–including, in particular, strategic decisions regarding policy and/or investment; and, eventually, to enable them to craft and pursue viable, sustainable transport and business strategies. The research is underpinned by literature data review.

This article proposes and develops a methodology that allows the estimation of the required minimum ground plan area for the facilities in a tramway depot, as well as the total area of the depot, taking into account the fleet size, tram length, number and type of performed activities. The study formulates simple mathematical equations to calculate the useful area of various depot installations in relation to the characteristics of the vehicle fleet (number and length of trams). It also presents tables of data, from which the total depot area can be estimated. Finally, the layouts of typical ground plans of tram depots are presented for tram fleets of between 15 and 83 vehicles and for tram lengths of 30, 35 and 40 m. From the presented results it is concluded that: (i) the construction of depots for 15 vehicles (very small depots) requires an area of 30–35 acres; (ii) the construction of depots for 45 vehicles (medium-sized depots) requires an area of 42–50 acres; and (iii) the construction of depots for 80 vehicles (large-sized depots) requires an area of 52–60 acres.