Cheminements piétonniers et exposition au risque

Travel surveys do not include all walking activity. The techniques that are employed tend to underestimate the proportion of walking in daily travel, and pedestrian exposure to traffic accident risk cannot be accurately computed from the resulting data. To overcome these shortcomings, the authors have developed an original survey technique that involves following and observing subjects in the Greater Paris Region. Recording the subjects’ trips (paying particular attention to walking episodes) during an ordinary day provides precise values for risk exposure that distinguish between the on-road and off-road components of walking activity. A number of different risk ratios are then computed, according to the geographical location and whether the pedestrian is walking on or off the road. These risk ratios are then compared to those that apply to motorists.     

Gibraltar: le projet de lien fixe entre intégration euroméditerranéenne et développement régional

This paper presents a socioeconomic examination of the project for a fixed link in the Strait of Gibralter. This project for a major link between Europe and the Maghreb which would take the form of a rail tunnel can be examined at two different spatial scales, that of the major trade networks which link Europe and the Maghreb and that of the areas which are located near the future points of access to the tunnel. If we pass over the problems which may be posed by the financing of this project (which studies have shown to be profitable), the geopolitical context of changing relations within Europe and the Mediterranean should be favourable to its construction. Its strategic (and at the same time symbolic) character is defined by its role as a link between the trans-European networks and the southwestern shore of the Mediterranean basin. This physical connection may nevertheless generate undesired or even counterproductive effects in the directly exposed economies on the southern side. Additional strategies could be considered for which the existence of a tunnel would constitute an opportunity. These are referred to as accompanying measures in French regional planning policy.     

Choix d'itinéraires et péage urbain Le cas du tunnel Prado-Carénage, à Marseille

This paper has a dual aim. Firstly, to identify the principal factors which explain route choice among drivers to Marseille in the context of urban tolling and secondly to assess marginally willingness to pay in order to save time and improve travel conditions. For this purpose we have used of the results of a 1995 stated preference survey of potential users of the Prado-Carénage tunnel in Marseille. Initially the paper describes the changeover values-of-time using a conventional price-time model. The sample has also been broken down into three homogeneous behaviour classes for each of which a Logit model has been calibrated. Analysis of the results has confirmed that there is no single value-of-time there is rather one (or several) distribution curve(s) of maximum willingness to pay. This illustrates the diversity of individual preferences and behaviours and confirms our starting hypothesis, namely that there is not a single value of time but as many values as there are individuals and that each individual has a large number of values depending on the nature of the trip in question.     

Certification des automatismes numériques dans les transports guidés : projets européens CASCADE et ACRuDA

This paper presents current work which deals with the certification of automatic train protection systems according to European standards and has three main sections. The first deals with the current situation as regards third party conformity certification on the basis of a reference document. The role of notified assessors and the requirements of European standards such as Cenelec 50126, 128 and 129 are discussed and the essential elements of the European high speed train interoperability directive are given. The second section summarizes the results of the Cascade project (Certification and Assessment of Safety-Critical Application Development) which is part of the Esprit III programme. This project deals with the harmonization of the various evaluation and certification approaches for safety critical software in railway applications. Its aim is to formulate a shared evaluation method to enable safety critical software to be certified by any notified assessor in a State in the European Union with the same criteria and rules, and in accordance with applicable European standards. The third section of the paper presents the Acruda project (Assessment and Certification Rules for Digital Architectures) which supplements the work on software carried out in Cascade. This project concerns the certification of hardware architectures and makes it possible to implement certification rules for the computers used to ensure the safety of train control systems.     

Dépenses de transport des ménages en Afrique subsaharienne méthodes et mesures appliquées au cas de Niamey

The knowledge about the proportion of household budget which Africans spend on urban transport is still poor. We have carried out an analysis of a household travel survey to provide some insight into this topic. This paper begins with a review of the literature that illustrates how much different estimates vary and goes on to discuss the effects of a number of methodological decisions, with regard to be robust, in particular as far as to expenditure is recorded, the type of data collection and the selection of an equivalence scale. With regard to an application in the city of Niamey, the authors explain the hypotheses they have made and describe sensitivity tests when different equivalence scales are applied. Although it would seem that travel surveys could benefit from methodological improvements, the results appear to be robust, in particular as far as selection of an equivalence scale is concerned. Because of high running costs, motor vehicle ownership is extremely restricted. Public transport use is a substitute for personal modes, but it is also expensive and a considerable burden on the budgets of the poorest households. Its use is therefore constrained, which limits the ability of low income groups for become truly integrated within the economic and social life the city     

Analyse des pratiques d'accompagnement des enfants et de leurs conséquences

It is more and more common to escort children, and adolescents in rural areas, to school, to see friends, to leisure activities, to the doctor's etc. Some elderly persons are also systematically escorted to activities. These escorting trips are mainly by car, with the mother (or the daughter) driving. Whether children are escorted or not varies according to their age, but the practice has becoming increasingly prevalent in Europe since the 1970s. In England children are allowed to travel unescorted average two and a half years later in 1990 than was the case in 1970 and in the same period the percentage of trips which are escorted has increased by a factor of three and a half. Road safety problems and general insecurity in the area where they live lead parents to escort their children. Most trips of this type are by car. The same situation applies in the former East Germany where many households have only recently acquired a car and where traffic is perceived as dangerous. Although this type of organization of daily family life provides short term opportunities, it nevertheless has long term negative impacts on the acquisition of travel independence by children and adolescents.     

Modèles linéaires généralisés appliqués à l'étude des nombres d'accidents sur des sites routiers: Le modèle de Poisson et ses extensions

Models that link accident frequencies at road sites with traffic volumes and road characteristics provide reference values which are of value when carrying out diagnostic studies and deciding on preventive measures. Such models can be developed using generalized linear modelling techniques, which are able to take account of the Poisson properties of accident frequencies at road sites. The Poisson models obtained for road sites are frequently everdispersed, so extended forms of the Poisson model (quasi-Poisson, negative binomial a high percentage of the studied sites, in which case zero-inflated models also have to be considered. This paper presents an overview of these methods which are illustrated by modelling the relationship between accident frequency site characteristics and traffic volume on a large sample of bends.     

Entre marche et métro, les mouvements intra-urbains des touristes sous le prisme de l’? adhérence ? à Paris et en ?le-de-France

The urban movement of tourists remains largely unknown, but the mobility of tourists contributes to the metropolitan process. Around the notion of ??adherence??, this article demonstrates how, in the Paris metropole, tourists rely mainly on walking and the use of the tube to travel within the city. The structurally different characteristics of walking and the use of the tube represent a theoretical opposition between the two types of movements that are differently ??adherent?? to the city. However, these mobilities complement each other. Indeed, the partial disconnection of the tube is addressed by the direct connection and proximity to the city allowed by the pedestrian means.