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10 Research products, page 1 of 1

  • Research software
  • Other research products
  • 2012-2021
  • Open Access
  • English
  • Hal-Diderot
  • HAL - UPEC / UPEM
  • Aurora Universities Network
  • Transport Research

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  • Open Access English
    Authors: 
    DELAUNAY, Teddy;
    Publisher: HAL CCSD
    Country: France

    On-demand Ride-Hailing services (RHs) now play an increasing role within many cities around the world. RHs might increase traffic congestion, vehicle ownership and access inequalities. RHs pose significant challenges for policymakers, and addressing these issues requires detailed information about RHs use. But research on RHs services, especially in African cities, remains scarce. In this respect, this research presents original data on the use and users of RHs in Kenya's capital, Nairobi, based on the results of an ad hoc survey designed by the author. This paper provides insights into who the users of RHs are, and their motivations for using RHs. Results show that RHs are extensively used in Nairobi (across all socio-economic groups, on a regular basis and way more for work-related trips than in many Western countries). In Nairobi, where only a minority of urban dweller have access to an individual motorized mode of transport, using RHs is gradually becoming necessary to access urban amenities. Nairobi's inhabitants are facing a growing RHs dependency, which calls in return to public regulation.

  • Open Access English
    Authors: 
    Blanquart, Corinne; Chen, Chia-Lin; de URENA, José Maria; Delaplace, Marie; Gastineau, Pascal; Koning, Martin; LIEDTKE, Gernot; Pagliara, Francesca; YOSHINO, Naoyuki;
    Publisher: T20 Saudia
    Country: France

    _; This proposal adopts a holistic approach to strategic transport investment by discussing the wider economic impacts (WEIs) analysis method in terms of several dominant and emerging methods. The WEIs analysis goes beyond the effects captured in a standard cost-benefit analysis (CBA). A CBA addresses the market for transport services and infrastructure access but neglects the wider impacts on other markets. These wider impacts usually relate to agglomeration, market power, and the behavioral adaptions of firms and households. The high uncertainty in land use changes indicates that WEIs tend to occur in different forms on multiple spatial scales, varying by place and time. Additionally, some activities, such as education, have no direct market value, but may indirectly contribute to the overall economic output and human capital development in cities and regions. Given that the conventional elasticity methods are not goal oriented, it is important to ensure that the WEIs analysis accounts for the stakeholder-specific costs and benefits. Assuming that it is possible to consider all WEIs through theoretical models, major efforts should focus on establishing and maintaining appropriate methodologies and tools. The social and environmental data needed to address biodiversity issues should also be improved and promoted. Complementary to the WEIs, understanding how the behavior of agents changes in response to the new transport options will help clarify the long-term implications of transportation. This will suggest new strategies (territorial appropriation), approaches/ techniques to feasibility, and ?place-based? interrelations, that is, specific interrelations in places. This last aspect is especially important in the current context of the COVID-19 pandemic, which has affected and will likely change transportation behaviors and transport demand in the dynamic future.

  • Open Access English
    Authors: 
    Simon, Gwendal; Darchen, Sébastien; Roitman, Sonia;
    Publisher: HAL CCSD
    Country: France

    Crime and insecurity are deeply entrenched in some cities. While we have rankings of the most dangerous cities in the world, this does not give a clear picture of how and why dangerous spaces develop in cities. We are analysing case studies from cities in France, Colombia, Brazil and Australia to understand the factors that lead to insecurity, and to examine possible solutions.

  • Other research product . Other ORP type . 2018
    Open Access English
    Authors: 
    Bocher, Erwan; Petit, Gwendall; Picaut, Judicaël; FORTIN, Nicolas; GUILLAUME, Gwenael;
    Country: France

    Présentation du projet NoiseCapture dans le cadre du séminaire Immersion Sciences 2018, organisé conjointement par l’Académiede Rennes, la région Bretagne et le CNRS.

  • Open Access English
    Authors: 
    Simon, Gwendal; Darchen, Sébastien;
    Country: France

    The regeneration of inner-city areas is a global challenge. Inner cities in France certainly have their problems, but the nation also has a good record of successful major urban regeneration projects. We have analysed three of these initiatives to understand what factors contribute to good regeneration outcomes. Urban regeneration can be defined as a holistic approach to revitalise under-used areas of the city. It's commonly associated, however, with the related challenges of gentrification, rising property values, and displacement of low-income groups. And these projects do not always achieve a sense of place.

  • Open Access English
    Authors: 
    de Bortoli, Anne; Feraille Fresnet, Adélaïde; LEURENT, Fabien;
    Publisher: HAL CCSD
    Country: France

    LCA of the BRT of Fort-de-France; Motorized modes of transportation, whether car or plane, bus or train, play a major role in developed societies. As they essentially trade energy against distance and speed of travel, their share in the overall consumption of energy and materials is high, making the reduction of that share an important objective for sustainability. This calls for both the systematic evaluation of environmental performance and the eco-design of transit modes. This twofold objective is addressed in the paper, which applies a Life Cycle Assessment (LCA) methodology to a transit mode, encompassing both infrastructure and vehicle fleets. The methodology is applied to a case study of a Bus Rapid Transit (BRT) system in Martinique, a French Caribbean island. The results show the contributions of the project's subsystems and life cycle phases to its environmental impacts, as captured by a set of 13 indicators. Impacts are normalized per passenger-kilometer. Comparison with other modes demonstrates the influence of vehicle occupancy rates and therefore the relevance of demand estimates in ex-ante evaluation. Finally, a sensitivity analysis is conducted to underline the respective impacts of input parameters on environmental impacts and to assess the potential of eco-design for BRT modes.

  • Open Access English
    Authors: 
    XIE, Xiaoyan; Leurent, Fabien;
    Publisher: HAL CCSD
    Country: France

    Technical Workshop “Imperial College London / Chair ENPC-STIF”, Marne-La-Vallée, France, Dec. 18th 2015.

  • Other research product . Other ORP type . 2014
    Open Access English
    Authors: 
    Perrin, Guillaume; Soize, Christian;
    Publisher: HAL CCSD
    Country: France

    Workshop on Numerical Methods for High-Dimensional Problems, Ecole des Ponts ParisTech, Marne-la-Vallee, April 14-18

  • Open Access English
    Authors: 
    Soize, Christian; Desceliers, Christophe; Guilleminot, Johann; Nouy, Anthony; Perrin, Guillaume;
    Country: France

    Workshop on Numerical Methods for High-Dimensional Problems, Ecole des Ponts ParisTech, Marne-la-Vallee, April 14-18

  • Open Access English
    Authors: 
    Perrin, G.; Duhamel, Denis; Soize, Christian; Fünfschilling, C.;
    Country: France

    This presentation deals with an innovative approach to analyze complex and nonlinear systems, which are excited by non-Gaussian and non-stationary random fields, by solving of a statistical inverse problem with experimental measurements. The methodology proposed is applied to the case of a railway system: a train is a nonlinear system with many degrees-of-freedom, which is excited by the track geometry and irregularities. These irregularities are of four types (horizontal and vertical alignment irregularities on the first hand, cant and gauge irregularities on the second hand), and vary from one track to another one, from one country to another one. As the track vehicle system is very non-linear, the characterization of the train dynamics cannot be achieved from the analysis of the train response on a single track portion but has to be made on the whole set of track conditions that the train can be confronted to during its lifecycle. In reply to these expectations, the track geometry of the French railway network has been continuously measured since 2007. Based on these measurements, which can be seen as experimental realizations of the track geometry random field, we develop a two steps methodology to analyze the influence of the track geometry variability on the train dynamics. In a first step, a stochastic modeling of the track geometry is proposed. Two decompositions are therefore used to identify the statistical characteristics of this random field. At first, using the Karhunen-Loève expansion, the considered random field is approximated by its truncated projection on a particularly well adapted orthogonal basis. Then, the random vector, which gathers the projection coefficients of the random field on this spatial basis, is characterized using a polynomial chaos expansion approach.The non-Gaussian non-stationary vector-valued random field is identified using the experimental measurements following the methodology presented in and consequently, constitutes a realistic track geometry stochastic modeling. Secondly, the track geometry variability is propagated to the train dynamics by solving a nonlinear stochastic dynamical problem. The results obtained are presented and analysed.

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