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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.

_; 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.

-; Etat des connaissances et questions qui se posent en 2020 à la CIE sur « Obtrusive lighting ».

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

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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.

Stage du 15/03/2018 au 15/09/2018 encadré par Juliette Marais IFSTTAR/COSYS/LEOST; The objective of the internship is to implement different weighting schemes i.e. i) Elevation and ii) CN0 as well as fault detection and exclusion (FDE) algorithms i.e. Local test and ii) forward back test to evaluate performance of real datasets. The prime focus is to detect how the local effects encountered in the railway environment impact the positioning solution and what could be done to reduce these errors thanks to weighting and FDE solutions.

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.

Invited presentation in conjunction with the grand opening of the MAPIL lab (Mizzou Asphalt Pavement and Innovation Laboratory) at the University of Missoury, Columbia (USA).http://moasphalt.org/wp-content/uploads/2017/03/MAPIL-Grand-Opening-March-27-Detailed-Program-final.pdf

Work In Progress Session, VRIPHYS 2017: 13th Workshop on Virtual Reality Interaction and Physical Simulation, 23-24 April 2017, Lyon, France.; Cubic symmetric Mass-Spring Systems (MSS) for simulating isotropic elastic materials are known to be intrinsically limited by the Cauchy constraints (rari-constant theory) involving Poisson ratio of exactly ν = 1/4. To mitigate the impact of this restriction, we propose a new solution based on correction forces, which authorizes to use MSS for materials with ν ∈]0; 0.5[. The validation of our model is evaluated by comparing its response to various deformations with Finite Element Model (FEM). The results show that the proposed model is relevant to simulate any compressible isotropic elastic material, and in particular nearly incompressible (Poisson ratio ≃ 0.5) biological soft tissues for which it is dedicated.