Alain L'Hostis

Université Gustave Eiffel

From a discussion about the mathematical properties of metrics, we identify three fundamental characteristics of distance, which are optimality, detour and break. We then explore the implications of these properties for transport planning, urbanism and spatial planning. We state that distances contain the idea of optimum and that any distance is as...

On the one hand the present globalisation process has only been made possible through a reduction in time–distances allowed by high-speed transport, and particularly through the development of air transport. On the other hand the metropolitanization process seen as the urban counterpart of globalisation is deeply associated with the development of...

Transit oriented development has become in the recent years a topic of high interest both for researchers and for practitioners. The French-German project Bahn.Ville 2 has the objective of testing the principles of an urbanism orientated towards rail by implementation on two regional railway lines (St. Etienne – Firminy, Lyon metropolitan region as...

L’Hostis (2015) has demonstrated that triangle inequality which is one of the four mathematical properties of distances, and whose role is to ensure the optimal character of distances, reveals some key aspects of distances and of geographical spaces. We elaborate from this demonstration by investigating the optimality of distances in empirical appr...

Accurate classification of rail transit stations is crucial for successful Transit-Oriented Development (TOD) and sustainable urban growth. This paper introduces a novel classification model integrating traditional methodologies with advanced machine learning algorithms. By employing mathematical models, clustering methods, and neural network techn...

This paper deals with the foundations of current and past mobility cultures, identifies emerging trends and main drivers that contribute to the shaping of the future European mobility cultures, and focuses on the role of communication. The methodology adopted to better understand this complex concept involved 3 major steps: first a literature explo...

The International Congress on Proximity Planning (June 26 - 28, 2024) has presented original research papers that explore the thematic and empirical challenges and opportunities that arise in the application of proximity-based planning in cities. Proximity is a planning principle with a tradition of more than a century, recently revived by circumst...

The significance of Ultimate Bond Stress-Slip (UBS-S) in reinforced Ultra-High Performance Concrete (UHPC) structures cannot be overstated, as it directly affects their load-carrying capacity, structural integrity, and long-term performance. A comprehensive analysis of the UHPC-Parallel Micro Element System (UHPC-PMES), including 144 specimens, eva...

The intermodal use of micromobility alternatives alongside transit networks significantly extends station catchment areas. However, the determination of the size of neighborhood stations often reveals a subset of users surpassing the measured distance threshold, prompting the question of why these intermodal passengers cover longer distances. This...

By accelerating the overcoming of space on certain relations, transport systems alter the accessibility of places and distort geographical time–space. Particularly in the case of discontinuous and tiered transport systems such as (high-speed) rail networks, effects on time–space can be highly selective and difficult to visualise. This paper compare...

Today, many cities are promoting sustainable mobility. Their policies have already reduced the car’s place, developed pedestrian and bicycle facilities, or renewed public transport. This raises the question of the effects of these policies on the conditions of access to everyday resources. Are the facilities for sustainable mobility configured in s...

Mobility hubs bring together, connect and provide users with several modes of transport. Cities adopt them to help reach many objectives simultaneously, mainly the reduction of air pollution, congestion, and car ownership. Each mobility hub is unique, but many of them have similar characteristics that allow them to be classified. Various typologies...

Rail-transit hub classification in TOD refers to the categorization of transit stations based on their level of connectivity and ridership and the potential for development around them as part of a Transit-Oriented Development (TOD) strategy. TOD, as an essential concept in developing smart cities and public transportation accessibility, has attrac...

The intermodal use of micromobility alternatives in combination with the transit network significantly expands station catchment areas. However, the determination of station neighborhood sizes often reveals a subset of users surpassing the measured distance threshold, prompting the question of why these intermodal passengers travel longer distances...

By accelerating the overcoming of space on certain relations, transport systems alter the accessibility of places and distort geographical time–space. Particularly in the case of discontinuous and tiered transport systems such as (high-speed) rail networks, effects on time–space can be highly selective and difficult to visualise. This paper compare...

Featuring rapid adoption rates in recent years, personal standing scooters, as a micromobility, represent a missing complement to the first and last mile of public transport. This paper examines intermodal trips involving private (e-)scooters and trains with the objective to investigate the influence of this intermodal combination on station catchm...

Geographical time-spaces exhibit a series of properties, including space inversion, that turns any representation effort into a complex task. In order to improve the legibility of the representation and leveraging the advances of three-dimensional computer graphics, the aim of the study is to propose a new method extending time-space relief cartogr...

We propose a geographical time-space model extending time-space relief cartography introduced by Mathis and L’Hostis [,,,]. The novelty of the model resides in the use of cones to describe the terrestrial surface instead of graph faces, and in the use of curves instead of broken segments for edges. The approach lies a the intersection of two domain...

La représentation de l'espace-temps géographique est une des fonctions essentielles de la cartographie, dès ses premières occurrences connues chez les Égyptiens, mais qui a fait l'objet de plusieurs tentatives pour dépasser les limites des cartes classiques. C'est l'objectif de la proposition de Philippe Mathis en 1990 qui repose sur des principes...

Geographical time-spaces exhibit a series of properties, including space inversion, that turns any representation effort into a complex task. In order to improve the legibility of the representation and leveraging the advances of three-dimensional computer graphics, the aim of the study is to propose a new method extending time-space relief cartogr...

The degradation of the sound environment contributes significantly to the external costs of mobility and is an obstacle to the development of cities. Action plans aiming at fighting traffic noise often take a long time to reach mature implementation. Therefore, it is advantageous to envisage how societal and urban changes and associated changes in...

Our goal is to establish a mathematical framework for the description of geographical distance in a comprehensive way. Geographical distance always refer to potential or realized movement between places, and these displacements obey the least effort rule. While this optimization of effort is well known to imply the Triangle Inequality in many situa...

Triangular inequality is one of the four mathematical properties of distance. Its respect derives from the optimal nature of the measurement of distance. This demonstration (L'Hostis 2016, 2017) reveals key aspects of distances and geographical spaces. We develop this argument by investigating the idea of the optimality of distance through a mathem...

In low-density urban areas, technologies are expected to play a significant role in tackling the ongoing mobility transition. A multidisciplinary research project focused on how a smart suburbs project, in Loos-en-Gohelle, France, could be promoted through resident participation. However, both the low level of smartphone ownership and the lack of a...

In low-density urban areas, technologies are expected to play a significant role in tackling the ongoing mobility transition. A multidisciplinary research project focused on how a smart suburbs project, in Loos-en-Gohelle, France, could be promoted through resident participation. However, both the low level of smartphone ownership and the lack of a...

Unlike the drivers of private vehicles, public transport (PT) users may perform secondary tasks during their primary travel activity. Moreover, Information and Communication Technologies may open up "multi-tasking" possibilities by allowing individuals to spend their travel time in more pleasant ways. This article proposes a tentative valuation of...

The objective of this paper is to establish a comprehensive view of societal trends that have an impact on mobility and logistics in the future. Based on a review of scientific literature, the output of European research projects and reports from consultancies, the result of this investigation provides a broad and comprehensive set of factors that...

Notre contribution cherche à mettre au jour la complexité qu'implique l'accompagnement d'une triple transition : 1) écologique, 2) démocratico-scientifique, 3) numérique. Notre parti pris a consisté à prendre au sérieux les compétences habitantes dans une démarche de recherche-action où le chercheur apprend en animant. Cette approche...

The objective of this paper is to establish a comprehensive view of societal trends that have an impact on mobility and logistics in the future. Based on a review of scientific literature, the output of European research projects and reports from consultancies, the result of this investigation provides a broad and comprehensive set of factors that...

Les histoires du transport et de l'urbanisme sont intriquées depuis l'aube de la civilisation. Aujourd'hui, il s'agit de rechercher la diversité des modes de transport dans la ville, de ne pas laisser un mode, la voiture, dominer les autres, et donc favoriser les alternatives - aujourd'hui les transports en commun - et les autres modes - marche, vé...

New high-speed rail transport infrastructures produce profound time-space changes that make new activities possible. Our aim is to measure the impact of such changes on potential business or leisure travel between cities.We develop a contact potential indicator (Törnqvist, 1970) that measures the possibility of making a trip to a distant location w...

La directrice générale de l'Ifsttar s'exprime sur les questions suivantes : Quelle est votre 'vision' de la mobilité intelligente ? Quels sont les axes stratégiques de l'IFSTTAR en matière de mobilité ? Dans ces domaines, sur quels programmes ou projets de recherche précis travaillez-vous ? De quelle manière le monde de la recherche et le monde ind...

New high-speed rail transport infrastructures produce profound time-space changes that make new activities possible. Our aim is to measure the impact of such changes on potential business or leisure travel between cities.We develop a contact potential indicator (Törnqvist, 1970) that measures the possibility of making a trip to a distant location w...

We investigate the meaning of the mathematical properties of distances in the fields of geography and economy. The key property for spatiality is the triangle inequality (TI) as ensurring the optimality of distance. We identify three different situations where several authors identify violations of the TI. We consider all of them as errors of inter...

Cet article présente une analyse de la connectivité des villes françaises en utilisant des mesures du "potentiel de contact" des villes. Une illustration des effets à attendre de la réalisation de la ligne TGV tours-Bordeaux est présentée.

L'article porte sur les relations qu'entretiennent le mode ferroviaire et la ville en mobilisant le rapport dialectique entre distance et proximité. La réflexion théorique est complétée par deux investigations sur la région urbaine de Saint-Étienne entre 2007 et 2010 et sur des gares parisiennes en 2013. Le mode ferroviaire permet de penser les art...

The success of Transit Oriented Development (TOD) or rail oriented development depends on several factors, among them the characteristics of the public transport system should not be neglected. In the typical tram-train approaches as exemplified in the Karlsruhe experience, a new transport systems is proposed from the association of specific rollin...

Transit Oriented Development (TOD) is a planning model that was introduced by Calthorpe (1993) in the United States. However, it has been applied in different international contexts: in high density urban environments (Asia) but also in medium density urban environments like in Australian cities (Perth, Brisbane) and in Canadian cities (Vancouver)....

Transit Oriented Development as sustainable mobility strategy is not part of French policy, in practice or in academic literature, even though a certain number of projects follow some of its principles. Reciprocally, from abroad, French experiences are not recognized as TOD, even when they could be. Scientific literature is needed in this direction...

Distance is a central element in the understanding and for the action on cities, on territories and on transport. However, distance has not been considered at its full potential in the disciplines that care about spatiality, namely geography, economy, psychology and sociology, and that constitute the main corpus used by the specialists of urbanism,...

Distance is a central element in the understanding and for the action on cities, on territories and on transport. However, distance has not been considered at its full potential in the disciplines that care about spatiality, namely geography, economy, psychology and sociology, and that constitute the main corpus used by the specialists of urbanism,...

This contribution aims at presenting and implementing an indicator called contact potential on a set of cities touched by the opening in 2017 of a new high speed rail line between Tours and Bordeaux. Two contributions are presented, on the methodological side, and on the empirical side. Firstly, on the methodological side, following several contrib...

Understanding distances between places is a fundamental task for the geographer, while the representation of distances constitutes one of the major functions of cartography. This is why time-distance representation constitutes a key tool for the contemporary geographer. The purpose of this chapter is, in a first step, to expose a set of solutions t...

Dans les villes européennes d’aujourd’hui, la tendance à la périurbanisation et le fait que la forme urbaine est de plus en plus polycentrique, conduisent à penser le développement urbain dans un cadre plus vaste. Dans la construction des régions urbaines, il est intéressant d’examiner dans quelle mesure le réseau de transport ferroviaire constitue...

Dans les villes européennes d'aujourd'hui, la tendance à la périurbanisation et le fait que la forme urbaine est de plus en plus polycentrique, conduisent à penser le développement urbain dans un cadre plus vaste. Dans la construction des régions urbaines, il est intéressant d'examiner dans quelle mesure le réseau de transport ferroviaire constitue...

The rules & roles of Public transportation in sustainable Communities in France & USA: French part

Le projet de recherche franco-allemand Bahn.Ville, urbanisme orienté vers le rail et intermodalité dans les régions urbaines allemandes et françaises, a consisté à identifier les principes et facteurs de succès d’un urbanisme orienté vers le rail et de les tester sur un terrain d’expérimentation, l’agglomération de Saint-Étienne. Une des recherches...

Introduction Accessibility Intermodality and multimodality Modeling the transport system: networks and graphs Example on an urban scale: access to the Lille campus Conclusion Bibliography

Afin de répondre aux enjeux actuels et futurs du développement urbain, l'idée d'un urbanisme orienté vers le rail (Pretsch et al. 2005) constitue une piste de réflexion et d'action dont le potentiel mérite d'être étudié. En regard de l'évolution historique du système urbain, le rail a joué un rôle structurant, qui se manifeste aujourd'hui sous la f...

Au sein de la thématique des interactions entre urbanisme et transport nous présentons ici à quelques éclairages donnés par le projet franco-allemand Bahn.Ville « Urbanisme orienté vers le rail et intermodalité dans les régions urbaines allemandes et françaises » réalisé dans le cadre de la coopération bilatérale DEUFRAKO.

Ce chapitre a pour objet de présenter les notions d’accessibilité multimodale et d’accessibilité intermodale. Nous proposons dans un premier temps de définir l’accessibilité. Dans le domaine des transports urbains mettrons l’accent sur les transports collectifs, en précisant les particularités de leur fonctionnement qu’il est nécessaire de prendre...

Transport, being an indispensable support for economic and social interaction, has a major role to play in the structuring of urban regions all over Europe. Accessibility is one of the basic factors of competitiveness, but also of access to services, while at the same time it is one of the major sources of pollution and of energy consumption. Acces...

Expérimenter de nouvelles façons de faire de l'aménagement et du développement urbain autour des gares ? C'est l'objectif du projet franco-allemand Bahn.Ville 2, recherche-action qui vise à promouvoir « un urbanisme orienté vers le rail ». Valoriser les investissements faits sur les lignes ferroviaires régionales périurbaines par des mesures d'acco...

On the one hand the present globalisation process has only been made possible through a reduction of time-distances allowed by high speeds, and particularly through the development of the air mode. On the other hand the metropolisation process seen as the urban counterpart of globalisation is deeply associated with the development of air platforms....

EURFORUM's Strategic Research Agenda addresses research issues in the particular field of urban transport considering all transport modes and focusing on intermodality for both passenger and freight transport. Technology-oriented as well as policy-oriented research is considered. The focus is directed on urban issues, including the transport betwee...

L'objet de cet article est d'exposer une approche du couple associant ville et transport ferroviaire. Le questionnement porte sur l'analyse des potentialités de développement des réseaux de transport ferroviaire, celle des potentialités de développement urbain, ainsi que celle de leurs interactions. Pour appréhender le couple associant transport fe...