Search Results (55)

Phosphogypsum, a by-product of phosphate fertilizer production, was predominantly used as a supplementary additive in recycled construction materials. However, there are few detailed studies on utilizing phosphogypsum as the primary component in inorganic cementing materials while achieving cost-effective detoxification. This study aimed to develop a harmless phosphogypsum-based inorganic cementing material (PICM) mainly based on phosphogypsum, in which cement, quicklime, and a stabilizer were used as additives. Harmful ions and acidity were first detected through X-ray fluorescence and ion chromatography and then harmlessly treated with quicklime. Compaction parameters, mechanical performance, X-ray diffraction analysis, moisture, and freezing resistance were characterized successively. The results illustrated that fluoride and phosphate ions were the primary soluble contaminants, whose leaching solution concentration can be reduced to 15.31 mg/L and undetectable with 2% quicklime through the mass proportion of phosphogypsum added and mixed. Meanwhile, the corresponding pH value was also raised to over 8. Cement content and quicklime were positively correlated with PICM’s maximum dry density. PICM with 25% cement and 2.5% stabilizer presented the highest unconfined compression strength, and flexural strength did not show significant regularity. PICM was mainly composed of quartz, gypsum, ettringite, and calcite, whose content decreased as cement content and quicklime content increased. Stabilizer, quicklime and cement content were positively correlated with PICM’s freezing and moisture resistance. Full article

This study explores the implementation and impact of autonomous vehicle (AV) systems, particularly in developing countries. While AVs promise enhanced road safety by reducing crashes, injuries, and fatalities, their adoption faces significant challenges, including public acceptance and infrastructure readiness. A mixed methods approach was employed, combining quantitative data from surveys of approximately 1500 randomly selected individuals and qualitative insights from in-depth interviews with policymakers, traffic engineers, and industry representatives. The quantitative analysis revealed high levels of perceived usefulness (78.8%), positive attitudes (87.78%), and expected benefits (86.09%) among respondents, indicating optimism about AVs’ potential to improve traffic efficiency and safety. However, concerns about technical reliability, cybersecurity, and the cost of infrastructure upgrades persist. Comparative analysis of physical and digital infrastructure highlighted significant gaps, particularly in road quality, markings, and internet connectivity. Policy implications emphasize the need for targeted public education to build trust and address safety concerns, regulatory reforms to ensure cybersecurity and ethical compliance, and strategic investments in infrastructure to meet AV requirements. Drawing on lessons from international contexts, the study recommends proactive stakeholder engagement and community outreach to align technological advancements with societal needs. These findings provide a roadmap for policymakers to navigate the challenges of AV adoption in Ethiopia and similar contexts, ensuring the integration of automation into sustainable and efficient transportation systems. Full article

This pilot study investigated whether good and bad access to waterbodies and parks have different impacts on walking and cycling in neighborhoods in urban areas. Focusing on Paris, France, the neighborhoods were classified based on their access to the two natural environments through GIS analysis. Active mobility, past behavior, trip purpose, and subjective evaluation were collected through an online survey. The subjective evaluation included infrastructure satisfaction and the perception of transport mode choice, urban area aesthetic level, safety, health, and preference for active mobility over car use. Descriptive analyses, Mann–Whitney tests, and Fisher’s exact tests were conducted to compare between two access groups and between cycling and walking. Active mobility was mainly performed for utilitarian purposes. Weekly cycling frequency was found to be lower than walking. Access to natural environments mainly impacts walking. Contrary to general belief, cycling frequency is higher in neighborhoods with bad access to waterbodies than in ones with good access. Contrary to expectations, this study found little significant effect on active mobility in the accessibility to both natural environments. This study also highlights the influence of dominant active mobility purposes in urban areas with respect to access to natural environments, and provides a subjective evaluation for active mobility. Full article

In railway stations, queues often form in front of the ticketing booths that provide ticketing services. Proper design of service systems is key to effectively managing these queues, as waiting time is a critical factor affecting customer satisfaction. This research focuses on optimising the location and configuration of queues in front of ticket booths to minimise waiting times and increase service efficiency. Passenger flow management at the station can be understood as the planning and implementation of the orderly movement of the crowd through the infrastructure. Using operational Markov chain analysis, we evaluate different queue configurations and the number of service providers in urban railway stations. The study specifically focuses on the case of the Poprad-Tatry railway station in Slovakia, where we propose the introduction of a common queue for all ticket booths. We propose the distribution of lines and their schedule, based on mathematical analyses, by creating designated service zones with a common queue in front of the ticket booths. The results show that this approach significantly reduces waiting times and improves overall system efficiency. This research focusses on solving the shortcomings in the design of queues in railway stations, specifically on the use of a common queue, thereby contributing to the improvement of passenger movement management. Full article

Although soil stabilization with cement and lime is widely used to overcome the low shear strength of soft clay, which can cause severe damage to the infrastructures founded on such soils, such binders have severe impacts on the environment in terms of increasing emissions of carbon dioxide and the consumption of energy. Therefore, it is necessary to investigate soil improvement using sustainable materials such as byproducts or natural resources as alternatives to conventional binders—cement and lime. In this study, the combination of cement kiln dust as a byproduct and zeolite was used to produce an alkali-activated matrix. The results showed that the strength increased from 124 kPa for the untreated clay to 572 kPa for clay treated with 30% activated stabilizer agent (activated cement kiln dust). Moreover, incorporating zeolite as a partial replacement of the activated cement kiln dust increased the strength drastically to 960 and 2530 kPa for zeolite ratios of 0.1 and 0.6, respectively, which then decreased sharply to 1167 and 800 kPa with further increasing zeolite/pr to 0.8 and 1.0, respectively. The soil that was improved with the activated stabilizer agents was tested under footings subjected to eccentric loading. The results of large-scale loading tests showed clear improvements in terms of increasing the bearing capacity and decreasing the tilt of the footings. Also, a reduction occurred due to the eccentricity decreasing as a result of increasing the thickness of the treated soil layer beneath the footing. Full article

This study develops an integrated methodology to incorporate public perspectives into the establishment and development of public transportation infrastructure systems. The approach involves surveying citizens to collect data, performing demographic analyses to identify differences between cities, and applying Multi-Criteria Decision-Making (MCDM) techniques to weight, scale, and integrate evaluation criteria in order to determine the optimal transportation option. The primary aim of this research is to incorporate public perspectives into transportation planning in developing countries and to promote stakeholder engagement for transportation initiatives in cities such as Baghdad, Iraq, and Tehran, Iran. First, an initial survey was conducted to identify the top three preferred criteria among 200 participants from both cities. The survey results revealed that the three most important criteria were safety, travel time, and reliability. Subsequently, a larger survey utilizing the Saaty scale was administered to capture citizens’ preferences, with a total sample size of 550 from Baghdad and 345 from Tehran. The weights of the criteria were then calculated using the Group Analytical Hierarchy Process (GAHP). Three transportation alternatives—monorail, Light Rapid Transit (LRT), and metrobus—were suggested by transportation experts to be evaluated and ranked using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) based on the weighted citizen preferences. The results indicate that for Baghdad residents, transportation safety is the most important priority, followed by reliability and travel time. However, LRT is rated as the most optimal transportation solution (0.721), followed by monorail (0.596) and metrobus (0.078). In Tehran, travel time represents the most preferred transportation attribute, followed by reliability and safety. The residents of Tehran are shown to prefer LRT (0.843), followed by monorail (0.370) and metrobus (0.143). Despite the similar ranking of transportation alternatives in the two cities, the performance scores differ between them, highlighting the importance of tailoring transportation planning to the unique preferences and needs of local communities. The validation of the results was conducted through sensitivity analysis to determine how variations in the criteria weights and input parameters affected the final rankings. Additionally, a stated preference survey was employed as a practical method to evaluate the robustness of the final ranking of the alternatives. Full article

A limited number of previous studies have focused on the selection of transportation routes considering sustainable development goals (SDGs). In this research, a methodology for selecting sustainable public transit (PT) routes is presented, consisting of generating a feasible initial route set, optimization, and assessment. Total welfare, road safety, and reduction in total emissions are indicators of the economic, social, and environmental dimensions, respectively. Based on the transportation model, the network structure, attributes, and emission rates are exported. The travel demand of PT is modified by modal share. Additionally, the safety performance function (SPF) is developed as a safety measure. Regarding optimization, the optimum routes are obtained by maximizing PT share and minimizing PT travel time. Then, the new routes are implemented, and the network is evaluated and compared with the existing scenario in light of sustainability indicators. The case study is Amman BRT. The results show that the new network is more sustainable than the existing BRT network and achieves better performance than the selected scenario of Amman city. The new network can reduce travel time by more than 13%, decrease total emissions by more than 17%, and alleviate the crash frequency by more than 14%. Full article

The estimation of carbon dioxide emissions in relation to the life cycle of road pavements is pivotal to quantify their sustainability at the design stage. This preliminary study assesses the carbon budgets concerning the production of aggregates and asphalt to build a new roadway stretch located close to Oslo (Norway), leveraging digital tools and environmental product declarations. First, the software Trimble Novapoint estimates the necessary quantity take-offs. Afterwards, the amounts of CO₂ generated during the production of the construction materials are appraised for the four main industries operating nearby. The results based on the corresponding environmental product declarations indicate that the carbon budgets show very small discrepancies among the considered suppliers. Full article

A planned interruption of railway infrastructure is a situation where the operation of the track line or the operation of railway transport is limited. If there is also a restriction on the railway infrastructure, it means there will be complications not only for passengers but, above all, for railway undertakings operating freight transport. However, because of the planned railway infrastructure interruption, the quality of services provided not only to passengers but also to freight transport is decreasing. The aim of this paper is to propose effective planned maintenance works based on the analysis and evaluation of the processes performed during the planned railway infrastructure interruption or restriction. The research describes the process of affected railway infrastructure from technical, cost, and safety points of view. A methodological procedure is proposed under the condition of the Czech infrastructure manager. The main method is the calculation of the costs for the railway infrastructure manager and railway operator during the infrastructure interruption. The application part is undertaken using two interrupted lines according to the established alternative timetable in the area of České Budějovice. Full article

The railway infrastructure projects in Thailand aim to shift transportation from roads to railways. This is crucial for transporting goods in emerging economies and increasing the demand for rail freight transport. However, several dynamic uncertainties hinder sustainable rail freight transport in Thailand. This study aims to identify the key factors and validate their effects on the success of the modal shift from roads to railways in Thailand. A total of 200 participants filled out a questionnaire delivered online and via postal service. The key factors were categorized into the following categories: the rail freight transport system, demand, and development factors in Thailand. The inter-relationship and connection of these factors were analyzed using SEM (structural equation modeling). The SEM results showed that all causal factors in the model had a positive influence on rail freight development in Thailand, which explained 98.3% of the variance in the factors influencing development. This study’s findings underscore the influential significance of rail performance, rail infrastructure, the legal framework, pricing, mode choice, and technology on the expansion of rail freight transport in Thailand. The rail freight transport system, rail performance, rail infrastructure, and Thailand’s rail infrastructure development strategy were significant direct predictors of rail freight expansion. An expansion of the rail freight transport system also leads to rail freight demand. The results of this study have positive implications for the government, railway practitioners, and policymakers to prioritize their focus on achieving rail freight transport as the national target. Full article

The integration between the building information modeling (BIM) methodology and the building energy simulation (BES) can contribute to a thermo-energetic analysis since the model generated and fed into BIM is exported to simulation software. This integration, also called interoperability, is satisfactory when the information flow is carried out without the loss of essential information. Several studies point out interoperability flaws between the methodologies; however, most of them occur in low-geometry-complexity models during quantitative experiments. The purpose of this research was to analyze the BIM/BES integration based on a quantitative and interpretative interoperability analysis of two buildings with complex geometries located on the UFU Campus (library and Building 5T) in Uberlândia, Brazil. To accomplish this, two geometries of each building were modeled, detailed, and simplified to analyze the data import, workflow, and model correction in the BES software. In the case of the library, the integration of Revit with DesignBuilder and IES-VE was analyzed, and in Block 5T, Revit was used with DesignBuilder and eQUEST. The BES software that presented the best integration with Revit for complex geometries was DesignBuilder, with the best performance being in the interpretative criteria. It was concluded that the simplification of complex geometries is essential for better data transfers. To determine the BES software that has better integration with BIM, a comprehensive evaluation is necessary, considering not only data transfers but also ease of working within BES software, the possibility of corrections in these, as well as the availability of tutorials and developer support. Full article

The objective of this research is to propose a public transport reorganization system that allows the improvement of urban vehicle flow. The lack of adequate transportation infrastructure and the existing disorder in the services provided by collective car, Microbus, Rural Public Transportation Van (Combi), Coaster, and mototaxis generate congestion in public transportation, especially during peak hours, resulting in environmental and noise pollution. The research was structured into four stages: data collection on the public and private transportation network, importing and creating the transportation network in the urban area of the Huánuco district, zoning and connectivity of the study area, and finally, creating the origin/destination (O/D) matrix for public transportation, supported by digital tools (ArcGIS 10.5, AutoCAD 2018, Excel 2017). To meet the demand of 135,343 passengers from South to North and 118,958 from North to South, the proposal includes establishing one main route and seven feeder routes, requiring 422 buses and road infrastructure, as depicted in the proposal This system will have exclusive lanes to operate the Mass Transit System, allowing it to accommodate 59% of users who prefer using public transportation. This proposal aims to offer an efficient and high-quality transportation system. Full article

The remarkable impact that e-scooters have had on the transportation system drives research on this phenomenon. The widespread use of e-scooters also poses several new safety issues, which should be necessarily studied. The aim of this paper points in this direction, investigating the main contributing factors, causes, and patterns of recorded e-scooter crashes, considering also different crash types and severity, using the City of Bari (Italy) as a case study. The crash dataset based on police reports and referring to the period July 2020–November 2022 (i.e., the first period of e-scooter implementation in the City of Bari) was investigated. Crashes were clustered according to several variables. No fatal crashes occurred, even though crashes mostly resulted in injuries (70%). Considering road type, divided roads were found to be less safe than undivided ones, due to higher mean speeds than on other roads and to a less constrained e-scooter driving behavior. Calm (off-peak) daytime hours seem to lead to more frequent e-scooter crashes with respect to both peak and nighttime hours, even if the latter hours are associated with an increased severity. Once controlled for exposure, season, lighting conditions, and the private/sharing ratio do not seem influential. E-scooters are more prone to be involved in single-vehicle and pedestrian crashes at segments than other vehicles, but they show similar crash trends than other vehicles (i.e., angle crashes) at intersections. As emerged from traffic surveys, not all e-scooter users were found to use cycle paths. Combining this information with crash data, it seems that not using cycle paths is considerably less safe than using them. Besides engineering measures and policies, awareness campaigns should be promoted to elicit safe users’ behavior and to tackle the several violations and misbehaviors emerging from the crash data. Full article

Creating new multimodal infrastructure in an existing transport network of an urban city is a challenging process. The responsible transport authorities have to pay special attention to the details regarding the accessibility and effectiveness of the new development, to avoid travelers’ confusion and network congestion. The subject of this paper is the assessment and optimization of the traffic network in the surroundings of the new multimodal depot of Thessaloniki’s future metro system with the use of the microsimulation software PTV VISSIM (version 2022). Five different scenarios were developed in collaboration with the city’s transport authority and evaluated into two stages, beginning with the whole traffic network, and then continuing with the analyzed intersections separately. The evaluation is based on Key Performance Indicators (KPIs), which were extracted by the software. According to the results of the base case scenario, the network functions satisfactorily, with slight delays. Regarding the future network, the operation of the new hub will strongly increase the traffic demand, while the proposed traffic network adjustments by the local authorities seem to cause significant delay problems. This paper aims to highlight the importance of using modeling tools during the design phase of a new infrastructure to create efficient, accessible, and sustainable infrastructures that enhance the public transport system. Full article

To meet the United Nations and European Union goals of reducing road crash fatalities and injuries, it is also relevant to address the negative externalities due to mega-events on the road network and the local communities, to assess the safety of the road network involved, and to implement appropriate measures for different road environments. Despite their relevance, the literature often overlooks social costs and risks associated with mega-events. This study presents an operating framework for rapidly assessing the safety of the Milano–Cortina 2026—“Via Olimpica” road—which will host a significant proportion of the traffic during the Winter Olympic Games in 2026. The framework proposes a simplified Road Infrastructure Safety Management (RISM) to address the unique challenges posed by the limited time available for screening and implementation by local authorities. The framework integrates four data sources and follows a seven-step procedure. It provides recommendations for improving road safety by identifying critical road sections and blackspots. Road authorities, practitioners, and public administrations may all benefit from the framework, as it makes it easier to prioritise safety improvements within time constraints. Full article