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This article reviews the critical issues surrounding the development of sustainable urban environments, focusing on the impact of transport and urban form on energy consumption and greenhouse gas emissions. The aim is to provide an overview of the state-of-the-art on the subject and to unravel what directions the literature suggests for sustainable urban planning. Current research and practices are synthesized, highlighting the interdependence of urban design and transportation systems in achieving sustainability goals. Important dimensions and practices of city planning and transport policies are explored, including urban form, urban sprawl, mixed land use, densification and infill, and urban public spaces, and how these directly influence transport dynamics, including modal choices and energy consumption. Innovative approaches in urban planning, such as transit-oriented development, and technological advancements, such as electric mobility, are also examined and their potential roles in sustainable urban transport. The conclusion underscores the urgency of adopting holistic and adaptable strategies to foster sustainable urban environments, calling for concerted efforts from policymakers, urban planners, and communities. Awareness of the conclusions can help municipal decision-makers in planning their cities for a sustainable future. Finally, the authors analyze important directions for future research and practical applications towards developing cities that are environmentally sound, socially equitable, and economically viable. [ABSTRACT FROM AUTHOR]

The high population density and tightly packed nature of some city centres make emergency planning for these urban spaces especially important, given the potential for human loss in case of disaster. Historic and recent events have made emergency service planners particularly conscious of the need for preparing evacuation plans in advance. This paper discusses a methodological approach for assisting decision-makers in designing urban evacuation plans. The approach aims at quickly and safely moving the population away from the danger zone into shelters. The plans include determining the number and location of rescue facilities, as well as the paths that people should take from their building to their assigned shelter in case of an occurrence requiring evacuation. The approach is thus of the location-allocation-routing type, through the existing streets network, and takes into account the trade-offs among different aspects of evacuation actions that inevitably come up during the planning stage. All the steps of the procedure are discussed and systematised, along with computational and practical implementation issues, in the context of a case study - the design of evacuation plans for the historical centre of an old European city. [ABSTRACT FROM AUTHOR]

Urban regeneration is increasingly a 'universal issue' and a crucial factor in the new trends of urban planning. It is no longer only an area for study and research, but it has become part of new urban and housing policies. Urban regeneration involves complex decisions as a consequence of the multiple dimensions of the problems such as special technical requirements, safety concerns, and socio-economic, environmental, aesthetic and political impacts, among others. This multi-dimensional nature of urban regeneration projects and the large capital investments required justify the development and use of state-of-the-art decision support methodologies to assist decision makers. This research focuses on the development of a multi-criteria approach for the evaluation of building conservation status in urban regeneration projects. This paper presents a web-based spatial decision support system (SDSS) to help decision makers in analysis of problems and in the definition of strategies and priorities of intervention. An example of an application to a real-world context is also presented. [ABSTRACT FROM AUTHOR]

Abstract: Fires, earthquakes, floods, acts of terrorism, nuclear accidents and other catastrophes that may occur in (or affect) urban areas, constitute an important concern for emergency and rescue services, such as fire departments and medical assistance. This paper introduces a multiobjective approach to identify evacuation paths and the location of shelters for urban evacuation planning. Six objectives including risks associated to paths and shelter locations, evacuation path lengths, and the final evacuation time from shelters to, for instance, hospitals, were considered in a mixed integer linear programming model. The proposed approach was tested for a simulated fire situation concerning the historical urban city center of an old European city (Coimbra, Portugal). The modeling approach may also support other emergency situations for which evacuation plans are pertinent. The solutions generated are compared in the objective space via various graphical techniques and represented via color-coded graphics in a Geographic Information System (GIS) where evacuation routes, rescue facilities and the respective building assignments are shown. [Copyright &y& Elsevier]

The Portuguese government has conceived a nationwide plan for the co-incineration of hazardous industrial waste at two existing cement plants located near the cities of Coimbra and Setúbal. This has been a problem of great concern for the populations of both cities, who have demonstrated strong opposition to the incineration of hazardous substances so close to the aforementioned urban centres. This paper describes a study that was carried out to evaluate possible environmental impacts on the city of Coimbra in particular and some of its urban facilities. A computerised environmental impact modelling approach for atmospheric dispersion, using a Gaussian model and its linkage to a geographical information system, was implemented. Using actual physical information, such as the direction and speed of more frequent winds, this study showed how the accidental emission of pollutants into the atmosphere by the cement plant at the north of Coimbra would affect some particularly sensitive urban facilities (e.g. hospital units and pre-primary schools) and all the inhabited area between the cement plant and the city centre. The regional health authority has requested the results obtained to design a plan of ambient monitoring. [ABSTRACT FROM AUTHOR]

Abstract: The location of multi-compartment sorted waste containers for recycling purposes in cities is an important problem in the context of urban waste management. The costs associated with those facilities and the impacts placed on populations are important concerns. This paper introduces a mixed-integer, multiobjective programming approach to identify the locations and capacities of such facilities. The approach incorporates an optimization model in a Geographical Information System (GIS)-based interactive decision support system that includes four objectives. The first objective minimizes the total investment cost; the second one minimizes the average distance from dwellings to the respective multi-compartment container; the last two objectives address the “pull” and “push” characteristics of the decision problem, one by minimizing the number of individuals too close to any container, and the other by minimizing the number of dwellings too far from the respective multi-compartment container. The model determines the number of facilities to be opened, the respective container capacities, their locations, their respective shares of the total waste of each type to be collected, and the dwellings assigned to each facility. The approach proposed was tested with a case study for the historical center of Coimbra city, Portugal, where a large urban renovation project, addressing about 800 buildings, is being undertaken. This paper demonstrates that the models and techniques incorporated in the interactive decision support system (IDSS) can be used to assist a decision maker (DM) in analyzing this complex problem in a realistically sized urban application. Ten solutions consisting of different combinations of underground containers for the disposal of four types of sorted waste in 12 candidate sites, were generated. These solutions and tradeoffs among the objectives are presented to the DM via tables, graphs, color-coded maps and other graphics. The DM can then use this information to “guide” the IDSS in identifying additional solutions of potential interest. Nevertheless, this research showed that a particular solution with a better objective balance can be identified. The actual sequence of additional solutions generated will depend upon the objectives and preferences of the DM in a specific application. [Copyright &y& Elsevier]

Abstract: The capacitated arc routing problem is a well-studied problem in the Transportation/Logistics/OR literature. The problem consists of identifying the minimum cost routes required to service (e.g., pickup or deliver) demand located along the edges of a network. Unfortunately, the problem belongs to the set of NP-Hard problems; consequently, numerous heuristic and metaheuristic solution approaches have been developed to solve it. In this article, an ant colony optimization based metaheuristic is presented. Modifications are introduced for various components of the ant colony metaheuristics; specifically for those associated with the “initial population”, the “ant decision rule” and the “local search procedure”. The new metaheuristic was tested on seven standard test networks for the capacitated arc routing problem. The results demonstrate that the proposed approach performs extremely well vis-à-vis the state-of-the-art metaheuristics for the problem. [Copyright &y& Elsevier]

Abstract: The location of hazardous material incineration facilities is an important problem due to the environmental, social, and economic impacts that they impose. The costs associated with the facilities and the risks placed on nearby populations are important concerns as are the distributions of these costs and risks. This paper introduces a mixed-integer, multiobjective programming approach to identify the locations and capacities of such facilities. The approach incorporates a Gaussian dispersion model and a multiobjective optimization model in a GIS-based interactive decision support system that planners can access via the Internet. The proposed approach is demonstrated via a case study in central Portugal where the national government has decided to locate a large facility for the incineration of hazardous industrial waste. Due to intense local and national opposition, construction of the facility has been delayed. The system has been designed so that it can be used by decision makers with no special training in dispersion modeling, multiobjective programming, or GIS. [Copyright &y& Elsevier]

Abstract: More efficient vehicle routing can improve a firm’s competitive advantage or increase the efficiency by which governmental agencies supply public services. More efficient routing can also reduce traffic congestion and air pollution which are growing problems in many urban areas. Unfortunately, the identification of the optimal solution to most vehicle routing problems is computationally intractable. This article presents a user-friendly spatial decision support system (SDSS) to generate vehicle routes for multiple-vehicle routing problems that serve demand located along arcs and at nodes of the transportation network. The SDSS incorporates a geographical information system (GIS) and heuristic solution procedures to generate routes, system-wide data, and maps, as well as individual vehicle route maps, directions, and data quickly. It accommodates realistic system specifics such as vehicle capacity and time constraints and network constraints such as one-way streets, and prohibited turns. The system was tested for trash collection in Coimbra, Portugal. In addition, the SDSS can be used for “what-if” analysis related to possible changes to input parameters such as vehicle capacity and maximum driving time. [Copyright &y& Elsevier]

Abstract: The shortest path problem is one of the classic network problems. The objective of this problem is to identify the least cost path through a network from a pre-determined starting node to a pre-determined terminus node. It has many practical applications and can be solved optimally via efficient algorithms. Numerous modifications of the problem exist. In general, these are more difficult to solve. One of these modified versions includes an additional constraint that establishes an upper limit on the sum of some other arc cost (e.g., travel time) for the path. In this paper, a new optimal algorithm for this constrained shortest path problem is introduced. Extensive computational tests are presented which compare the algorithm to the two most commonly used algorithms to solve it. The results indicate that the new algorithm can solve optimally very large problem instances and is generally superior to the previous ones in terms of solution time and computer memory requirements. This is particularly true for the problem instances that are most difficult to solve. That is, those on large networks and/or where the additional constraint is most constraining. [Copyright &y& Elsevier]

The debate on the ideal urban layout, or form has long been an active topic of research. As cities expand and population demands rise, the quest for efficient and sustainable urban designs gains greater significance, necessitating objective and quantitative evaluation of their performance. This article adds to the debate by presenting a multicriteria analysis of city performance, based on quantitative indicators obtainable from geographic information systems calculations, which focus on sustainability and physical pleasantness issues. Indicator values were derived for a real city, its infill version, and five redrafts as classic city models existing in the literature. The city layouts were then compared using the TOPSIS multicriteria ranking method, results showing a preference for the more compact urban layouts due to the multiple advantages of having shorter distances between supply and demand points. The methodology provides quantitative insights on city performance and efficiency and can be used to compare options for city expansions or major urban regeneration projects. [Display omitted] • A multicriteria methodology for assessing city performance is presented. • Quantitative indicators related to sustainability and pleasantness are proposed. • A comparative study benchmarked a real city with classic urban models using TOPSIS. • Results favor compact urban layouts. • Provides policymakers with quantitative analysis tools for urban planning decisions. [ABSTRACT FROM AUTHOR]

A multi-objective model for managing railway infrastructure asset renewal is presented. The model aims to optimize three objectives, while respecting operational constraints: levelling investment throughout multiple years, minimizing total cost and minimizing work start postponements. Its output is an optimized intervention schedule. The model is based on a case study from a Portuguese infrastructure management company, which specified the objectives and constraints, and reflects management practice on railway infrastructure. The results show that investment levelling greatly influences the other objectives and that total cost fluctuations may range from insignificant to important, depending on the condition of the infrastructure. The results structure is argued to be general and suggests a practical methodology for analysing trade-offs and selecting a solution for implementation. [ABSTRACT FROM AUTHOR]

For the past few years, the world has been facing one of the worst pandemics of modern times. The COVID-19 outbreak joined a long list of infectious diseases that turned pandemic, and it will most likely leave scars and change how humans live, plan and manage urban space and its infrastructures. Many fields of science were called into action to mitigate the impacts of this pandemic, including spatial and transport planning. Given the large number of papers recently published in these research areas, it is time to carry out an overview of the knowledge produced, and synthesising, systematising and critically analysing it. This paper aims to review how the urban layout, accessibility and mobility influence the spread of a virus in an urban environment and what solutions exist or have been proposed to create a more effective and less intrusive response to pandemics. This review is split into two avenues of research: spatial planning and transport planning, including the direct and indirect impact on the environment and sustainability. [ABSTRACT FROM AUTHOR]

This paper reviews the state of the art on autonomous vehicles as of 2017, including their impact at socio-economic, energy, safety, congestion and land-use levels. This impact study focuses on the issues that are common denominators and are bound to arise independently of regional factors, such as (but not restricted to) change to vehicle ownership patterns and driver behaviour, opportunities for energy and emissions savings, potential for accident reduction and lower insurance costs, and requalification of urban areas previously assigned to parking. The challenges that lie ahead for carmakers, law and policy makers are also explored, with an emphasis on how these challenges affect the urban infrastructure and issues they create for municipal planners and decision makers. The paper concludes with strengths, weaknesses, opportunities, and threats analysis that integrates and relates all these aspects. [ABSTRACT FROM AUTHOR]

Compactification of cities, i.e., the opposite of urban sprawl, has been increasingly presented in the literature as a possible solution to reduce the carbon footprint and promote the sustainability of current urban environments. Compact environments have higher concentrations of interaction opportunities, smaller distances to them, and the potential for increased active mode shares, leading to less transport-related energy consumption and associated emissions. This article presents a GIS-based quantitative methodology to estimate on how much can be gained in that respect if vacant spaces within a city were urbanized, according to the municipal master plan, using four indicators: accessibility, active modal share, transport energy consumption, and a 15-minute city analysis. The methodology is applied to a case study, in which the city of Coimbra, Portugal, and a compact version of itself are compared. Results show the compact layout improves all indicators, with averages per inhabitant improving by 20% to 92%, depending on the scenario assumed for cycling, and is more equitable. [ABSTRACT FROM AUTHOR]

This article presents a methodology to estimate the maximum potential impact of a well-built and conserved cycling infrastructure, measured as modal share for accessibility trips, as well as the associated transport energy that can be saved in those trips. The methodology uses Geographic Information Systems (GIS) to estimate active trip probabilities, from which the output variables can be obtained. It was applied to a case study of a mid-sized city in Southern Europe, and results show that an adequate cycling infrastructure can achieve cycling mode share in that city on par with the world's most cycling-friendly cities. Concerning transport energy, a full-cycling scenario is estimated to reduce fossil energy intensity by approximately 20%, mainly by inducing a mode change for residents on the closest outskirts. It is also argued that cycling investment in commuting routes will have the most impact on reducing fossil transport energy. [ABSTRACT FROM AUTHOR]

A bi-objective decision aid model for planning long-term maintenance of infrastructure systems is presented, oriented to interventions on their constituent elements, with two upgrade levels possible for each element (partial/full repairs). The model aims at maximizing benefits and minimizing costs, and its novelty is taking into consideration, and combining, the system/element structure, volume discounts, and socioeconomic factors. The model is tested with field data from 229 sidewalks (systems) and compared to two simpler repair policies, of allowing only partial or full repairs. Results show that the efficiency gains are greater in the lower mid-range budget region. The proposed modeling approach is an innovative tool to optimize cost/benefits for the various repair options and analyze the respective trade-offs. [ABSTRACT FROM AUTHOR]

The importance of cycling as a sustainable transport mode has been widely recognised, and recently, its effectiveness in mitigating the spread of infectious diseases has also been under the spotlight. Fostering its use requires developing and deploying decision tools to help authorities assess the performance of their cycle infrastructure for maintenance and improvements. This paper presents a multicriteria methodology based on engineering best practices and uses the Elimination and Choice Translating Reality (Electre) Tri method to assign segments of the cycling network to predefined performance classes, aiming at maintenance planning. The approach is demonstrated with a case study, which also proves the scalability of the data-collection procedure of the method. The case study results show that lack of safety and inadequate intersections are the main problems. These stem mostly from non-existent segregation between motorised traffic and cyclists, both along the segments and at intersections. This is typical of cities that, over the years, have prioritised motorised transportation. [ABSTRACT FROM AUTHOR]

This paper builds upon previous work entailing, in a first stage, the development of a geographic information system based environmental modelling approach and, in a second stage, the development of a stand-alone, more generic integrated spatial decision support system. The latter system was designed to address general spatial decision problems in a way that enables interactive definition of mathematical models, the spatial entities involved and their attributes. This manuscript focuses primarily on a further development to implement a multicriteria modelling framework supporting sophisticated evaluation and comparison of hypothetical alternative scenarios in the context of spatial decision problems. Typically several conflicting and generally incommensurable criteria are involved, which derive from the multidimensional nature of most of the decision problems. In such circumstances, multicriteria techniques are recommended to be used in the analysis process. Overall, at the very beginning, the decision maker is not fully aware of the whole problem in hand and hence an effective learning process needs to be undertaken. Operating interactively with the methods above, either simultaneously or following a given sequence, the decision maker may become effectively acquainted with the whole problem by investigating possible coherences among results obtained and also by analysing sensitivity of variations in input data. [ABSTRACT FROM AUTHOR]

This paper introduces the concept of pedestrian or walking friendliness (WF), and presents a methodology for obtaining maps thereof. WF is a quality of walking indicator, defined for any given origin in a city, which combines accessibility measures, based on impedance between that origin and destinations, with performance scores for the pedestrian infrastructure linking those origins and destinations. The methodology uses geographic information systems to obtain WF values and represent them in a map. The approach is demonstrated through a case study for the city of Coimbra, Portugal, for which friendliness maps were derived. The procedure and maps that were produced can be scaled to any size of city. [ABSTRACT FROM AUTHOR]

Sustainability worries related to the intensive use of energy by automobiles and traffic congestion issues have encouraged decision makers to look for alternative solutions, leading to an emerging shift towards soft/active transport modes. The bicycle, a very efficient mode of transport, is a soft travel mode that can be adopted in most cities, contributing to urban sustainability given the associated environmental, economic and social advantages. Cycling, however, also has its deterrents. Among these, it is recognised that slopes play an important role in influencing the choice for this mode of travel. The purpose of this paper is to present methods to analyse a hilly city's suitability for cycling, in what concerns relief, with the aim of identifying locations for implementation of hard aid devices that restore connectivity between most parts, or even the whole, of the city. The methodology proposed makes use of appropriate service areas. Geographical information systems technology was used to implement the methodology and the approach is demonstrated with a case study for the city of Coimbra, Portugal. This combined approach helps decision makers to plan the city in a sustainable way. [ABSTRACT FROM AUTHOR]

Evacuation planning is an important component of emergency preparedness in urban areas. The number and location of rescue facilities is an important aspect of this planning, as is the identification of primary and secondary evacuation routes for residents to take. This article introduces a multiobjective approach to identify these aspects of evacuation planning. The approach incorporates a multiobjective model into a geographical information systems–based decision support system that planners can access via the Internet. The proposed approach is demonstrated with a case study for the City of Coimbra, Portugal, for evacuation during major fires. Although presented in this context, this approach is applicable to other emergency situations such as earthquakes, floods, and acts of terrorism. [ABSTRACT FROM AUTHOR]