Publicações

GHISOLFI, Verônica; TAVASSZY, Lóránt; CORREIA, Gonçalo; CHAVES, Gisele; RIBEIRO, Glaydston. Dynamics of freight transport decarbonisation: a conceptual model. Journal of Simulation

Resumo: As part of the global efforts to mitigate climate change, policymakers are designing measures to reduce the carbon emissions of the freight transport system. As global agreements for decarbonisation specify strict time windows, it is important to understand the speed at which the transport system is capable of changing. Our paper proposes a causal loop diagram based on System Dynamics that qualitatively maps the system’s causal and dynamic responses to five key decarbonisation strategies. As the main contribution, this conceptual model provided a broad overview of the freight system, formed by subsystems that interact with each other through feedback loops, forming its dynamic behaviour. Through this conceptual modelling effort, we can identify the rebound effects of policies over the whole system, which could defeat the desired decarbonisation results. The model pointed out policies and feedback loops as the dynamic levers to promote freight decarbonisation and influence the system’s dynamic responses.

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SILVEIRA-SANTOS, Tulio; PORTUGAL, Licinio; RIBEIRO, Paulo

SILVEIRA-SANTOS, Tulio; PORTUGAL, Licinio; RIBEIRO, Paulo. Using a Discrete-Event Simulation Model for Evaluating the Operational Performance of Toll Plazas. Journal of Infrastructure Systems, 2023

Resumo: Toll plazas are commonly described as a potential bottleneck due to the collection process at specific points on the highway. In a highway concession model, tolls are used to cover the majority of infrastructure costs. However, not all existing road concessions have toll plaza–related key performance indicators (KPIs), resulting in less efficient operations for transport managers and road users. To address this issue, this paper presents a discrete-event simulation (DES) model for policy analysis and the model for the planning, management, and evaluation of toll plazas using an extensible simulation package with animation capabilities, built by selecting modules that contain process features. The DES describes situations in which entities (vehicles) arrive, wait in the queue (if necessary), and then are attended to before leaving the system, either directly or indirectly. As a result, the simulation is based on discrete events (arrivals and departures) and statistical process data. This paper examines data from Brazil’s first public–private partnership (PPP) project in the area of road infrastructure and analyzes the toll plaza in Itaúna/MG using a case study methodology. The DES model was used in this case study, and the results show that the toll plaza was in good operating condition during the peak hour analyzed because the vehicular flow was lower than the system capacity. The willingness to pay the toll rate through the concept of open road tolling or a free-flow system, on the other hand, would provide significant benefits to road users because it would significantly reduce the time it takes to cross the toll plaza. The developed DES model assists toll plaza managers in making decisions while keeping in mind the need to comply with the operational efficiency measures agreed upon in the concession contracts.

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ABREU, V.H.S.d.; SANTOS, A.S.; MONTEIRO, T.G.M. Climate Change Impacts on the Road Transport Infrastructure: A Systematic Review on Adaptation Measures. Sustainability 2022, 14, 8864.

Resumo: Road transport is one of the main contributors to increasing greenhouse gas (GHG) emissions, consequently aggravating global warming, but it is also one of the sectors that most suffer from climate change, which causes extreme weather events. Thus, strategies, also called adaptation measures, have been discussed to minimize the impacts of climate change on transport systems and their infrastructure; however, a knowledge gap is evident in the literature. Therefore, this article develops a systematic review with a bibliometric approach, still scarce in the literature, in renowned databases, focusing on studies developed on adaptation measures for road infrastructure. The results show that, since the development of the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), an increasing amount of studies on the theme have been published in recognized journals such as Science of the Total Environment, Energy and Buildings and Urban Climate, analyzing climate threats such as intense precipitations and high temperatures that have led to biophysical impacts such as flooding and urban heat island. In addition, for each type of adverse weather condition, many impacts on road infrastructure can be listed, as well as ways to detect these impacts, and adaptation measures that can be used to minimize these problems.

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HERSZENHUT, Daniel; PEREIRA, Rafael; PORTUGAL, Licinio; OLIVEIRA, Matheus. The impact of transit monetary costs on transport inequality. Journal of Transport Geography, 2022

Resumo: Transport inequality analyses are often informed by accessibility estimates based solely on travel time impedance, ignoring other elements that might hinder access to activities, such as the monetary cost of a trip. This paper examines how and to what extent simultaneously incorporating both time and monetary costs into accessibility measures may impact transport inequality assessment. We calculate job accessibility by transit in the city of Rio de Janeiro, Brazil, using cumulative opportunity measures under distinct combinations of temporal and monetary thresholds, and compare how inequality levels vary across different scenarios. We find that the most common research practice of disregarding monetary costs tends to overestimate accessibility levels. However, stricter monetary constraints do not necessarily result in more unequal scenarios. How accessibility inequality is affected by monetary costs is highly dependent on what combinations of temporal and monetary cut-offs are considered in the analysis. In the case of Rio, opting for lower monetary thresholds when looking at shorter trips leads to inequality levels lower than those found in the no monetary threshold scenario, but results in higher inequality levels when allowing for longer trips. We find that the impact of monetary costs on transport inequality estimates depend on a complex interaction between fare policies, the spatial organization and operational characteristics of transit systems, and the spatial co-distribution of opportunities and residential locations. The paper thus highlights that conclusions and policy recommendations derived from transport inequality analyses can be affected in non-intuitive ways by the interplay between temporal and monetary constraints. Future research should investigate how different combinations of travel time and monetary costs thresholds affect inequality estimates in different contexts.

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FONTES, Fabio; DONATO, Marina; GOUVEIA, Bruno; SANTANA, Glaudeny; SILVA, Marcelino. Analysis of the influence of tropical soil classification methods on railway subgrades according to repeated load triaxial (RLT) and light weight deflectometer (LWD) tests, Case Studies in Construction Materials, Latest issue, Volume 17, 2022.

Resumo: Recently, non-destructive in-situ tests have emerged that can predict the resilient modulus (MR) of materials that make up railway sidewalk layers in an agile and low-cost manner. These are in contrast to laboratory tests that require more infrastructure and are more time-consuming to perform. However, few studies have been directed to the resilient behavior compared to in-situ and laboratory tests for soils classified as tropical. This paper aims to determine the relationship between the estimated modulus of elasticity (ELWD) and the estimated resilient modulus (MR) from the repeated load triaxial test (RLT) for use in tropical soil railway subsoils. The samples of subgrade soils belong to a railway stretch in Brazil, present in the states of São Paulo-SP and Minas Gerais-MG, which has large circulation of minerals and commodities. The soils are classified as lateritic and non-lateritic according to the Brazilian Miniature, Compacted, Tropical (MCT) methodology, in addition to grain size, compaction, LWD and RLT tests. It is noted that the modulus of elasticity (ELWD) tends to decrease according to the increase in strain obtained in LWD. For soils classified as lateritic, as the soil moisture increases the ratio between the moduli obtained by RLT and LWD tend to increase. However, non-lateritic soils have the opposite performance, i.e., the ratio between the modulus of the tests decreases with increasing moisture. In this study, the LWD test is a possible viable alternative with good accuracy and effectiveness for geotechnical investigations in tropical soils.

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