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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.

FAEE SEMINAR; Battery Electric Vehicles (BEVs) are essential for reducing greenhouse gas emissions related to the transport sector towards meeting global emissions targets. Although this technology is gaining much attention, techno-economic barriers hinder the widespread of BEVs, namely the high investments, the limited autonomy, and the lack of public-charging infrastructure. A bigger battery leads simultaneously to more autonomy and higher-priced BEV, due to the battery-pack cost. Deploying more public chargers, a solution for limited autonomy BEVs, is facing other obstacles: vehicle-charger adaptability in terms of charging power, and additional investments for charging operators. Therefore, this paper aims to find the most cost-efficient solution(s) of battery capacity and charging power combination(s), considering technoeconomic factors. Based on French travel surveys data, we simulate the needs of 12 scenarios of 5,000 identical privately-purchased BEVs, by changing their battery capacity for both urban and rural areas, before determining the optimal number of charging stations. We then analyze the BEV owner and the charging operator business models in order to conclude with win-win situations for both parties. Results show cheaper investments in charging infrastructure, especially 22 kW charger, rather than in bigger batteries. For urban (rural) areas, purchasing a 35 to 50 kWh BEV (65 kWh BEV for rural) and deploying 22 and 50 kW chargers (50 kW for rural) proves the most cost-efficient and profitable solutions for both BEV owners and charging operators. We finally recommend charging operators to review their charging tariffs, and to take into account the acceptability of customer.

Il y a quelques jours, Stephen Roach, économiste renommé, a publié un remarquable article d'opinion dans le "Financial Times". Il a esquissé un avenir de stagflation (faible croissance et de forte inflation) en raison de la fragilité croissante des chaînes et de la baisse de la demande des consommateurs que le confinement a imposée.Selon nous, Stephen Roach a fondamentalement tort. En substance, cet argument réitère la crainte de nombreux nouveaux économistes classiques qui s'inspirent de l'affirmation de Milton Friedman selon laquelle l'inflation est toujours un phénomène monétaire.

_; 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 ».

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.

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

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.

Document CGET

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.