Demande de transport de personnes: une théorie unifiée de l'urbain à l'intercontinental Première partie: modalités de réalisation d'un voyage potentiel

This paper proposes a theory which links some of the characteristics of trips made by individuals to the travel price and time provided by transport supply, with reference to the socio-economic context. This model appears to be able to reproduce the phenomena that are observed when there is a change in the supply or context on a given origin-destination link. However, above all, the same model can also reproduce those phenomena (changes in urban development aside), which are different in an urban and an interurban context: greater personal mobility, shorter period away from home, lower value of time among travellers, different modal split for trips, slower increase in the number of trips as a result of the socio-economic context, etc. The first part of the paper shows how each of an individuals potential journeys may be characterized by wishes concerning different aspects of the journey and how the different alternatives for the journey in a given context of transport and accommodation supply can be assessed with reference to the gap between wishes and real characteristics. The second part shows how it is possible to determine the total population of journeys made with reference to both the context and supply. The theory has been illustrated by numerical results obtained for a variety of situations which are representative of urban and interurban areas.     

Le projet isis: une interface intégrée de sécurité

In order to meet safety, reliability and availability constraints for passenger transport systems, the manufacturers of railway control-command systems must develop specific computer architectures for signalling, switch control and automatic driving applications. Typically, these systems consist of a core (with one or two central processing units) and peripherals via which the computer communicates with external devices. In the case of some applications, for example signal boxes, the architecture contains a very large number of fail-safe True or False outputs. These functionalities are currently performed by conventional technology that uses discrete components or hybrid circuitry.     

L'information sur les durées de parcours: Modélisation de l’activité cognitive impliquée

In recent years some urban express roads have been equipped with journey time information systems, which are greatly appreciated by drivers. It has been observed that the messages help drivers take appropriate decisions and then better manage the time they spend travelling and deal better with congestion. In order to understand why the content of the messages leads to the behaviour in question we have developed a hypothetical architecture for the mental process demanded by the messages. This paper presents the cognitive model we have developed, which is based on knowledge networks.     

Information routière par RDS-TMC: enjeux de l'interopérabilité

There was a range of systems and technologies for broadcasting road traffic information in different countries in the European Union and interoperability between the various systems must be achieved to enable road users to use the same on board equipment in different countries so that they can receive the same information service in their own language throughout a journey, whether local, regional, national or international. This paper mainly deals with the broadcasting of road, traffic information via RDS-TME and begins by describing some technical features of this medium. If the proceeds to examine issues of interoperability between RDS, TME based road traffic information systems.     

Fusion de données pour l'estimation des temps de parcours via la théorie de l'évidence

The emergence of new information technologies and the transformation that has occurred in traffic management have both increased drivers' already considerable need for road traffic information. The travel time is one of the forms in which this information is presented, and a number of systems are based on its dissemination. In this context, this indicator is used as a measure of the impedance (or cost) of routes on the network and/or a congestion indicator. This raises the problem of estimating travel times with an acceptable degree of accuracy, which is a particularly difficult task in urban areas as a result of difficultes of a theoretical, technical and methodological nature. Thus, in order to find out the traffic conditions that prevail on an urban road, the traffic sensors that are usually used to measure traffic conditions are ineffective under certain circumstances. New measurement devices (cameras, GPS or cellphone tracking, etc.) mean that other sources of data are increasingly used in order to supplement the information provided by conventional measurement techniques and improve the accuracy of travel) time estimates. As a result, travel time estimation becomes a typical data fusion problem. This study deals with a multisource estimate of journey times and attempts to provide a comprehensive framework for the utilization of multiple data and demonstrate the feasibility of a travel time estimation system based on the fusion of data of several different types. In this case two types of data are involved, data from conventional induction loop sensors (essentially flow and occupancy measurements) and data from probe vehicles. The selected modelling framework is the Dempster-Shafer Evidence Theory, which has the advantage of being able to take account of both the imprecision and uncertainty of the data. The implementation of this methodology has demonstrated that, in each case, better results are achieved with fusion than with methods based on a single source of data and that the quality of the information, as measured by correctly classified rates, improves as the degree of precision required of the estimate is increased.     

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.     

Un scénario périurbain de route automatisée

A scenario for a suburban automated highway with the objective of reducing congestion is described. Starting from a reference situation similar to a current traffic lane, the authors consider the influence of a number of parameters on the achievable capacity of an automated section of road. These parameters are used to estimate safe following distances which are computed with the aim of avoiding collisions in the event of sudden braking. They then consider the number of collisions in the presence of a brick wall type obstacle on the carriageway. Ramp metering based on a macroscopic approach leads to a loss of capacity, which we overcome by implementing a management technique that integrates individual vehicles in the stream. Lastly, a general architecture for the scenario with several control and co-ordination layers is proposed.     

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     

Détection de stationnarités anormales dans les couloirs du métro

One of the factors which discourages use of public transport is the feeling of insecurity. In order to overcome this, the operators of metro networks are attempting to find techniques to detect more incidents or anomalies rapidly. It is within this framework, as part of the European cromatica project, that research has been undertaken at inrets by the video team in the Traffic Analysis and Control Department (dart). This paper will concentrate on the detection of abnormal stationarities in metro corridors. Operators wish to identify events of this type as a prolonged stationarity may denote the presence of a drug pusher, an illicit vendor, a thief watching a potential victim, a homeless person, a person suffering from illness, a person who has had a fall, or an abandoned object. The paper firstly gives an account of the developed system and its context and then describes the image processing techniques which have been used. The results obtained with real complex situations are then presented.     

Analyse de la prise en compte de la sécurité routière dans les plans de déplacements urbains

At the time when Urban Travel Plans (utps) are being introduced it is important to see how they take safety into account, certu's analysis of a dozen recent docuements shows the position occupied by road safety in utps, reveals the stated aims of the utps, identifies local actions aimed at improving road safety and highlights current or foresedable problems in the implementation of utps. The analysis shows that the way safety is taken into account varies considerably from one city to another. The desire to introduce measures to improve safety is usually present, but there is uncertainty as to how to tackle the issue. The examples of methods and actions that are given in this paper may provide some ideas which merit further examination for utps in the future. It is already obvious that utps will be responsible for profound changes in urban travel and its safety, and the results obtained over the next five years will doubtless have important consequences for the cities of tomorrow.     

Une caractérisation de l'émission acoustique des véhicules au cours des déplacements

Traffic noise is usually measured at fixed points whereas in reality vehicles move and generate noise throughout their trip. This paper therefore puts forward a new method of identifying noise emissions which takes account of the trip as a whole. We have made use of the concept of standard kinematic sequences (which are the elements which form all car trips) and have introduced a new acoustic index to characterize the noise emissions of a vehicle during a sequence. We have achieved this by adapting conventional highway acoustic indices to the way sequences are defined and used. We have calculated examples of these indices from acoustic recordings of isolated vehicles on a test track and from standard sequences.     

Quelle place pour la sécurité routière dans les plans de déplacements urbains? Entre intégration et diffusion,le cas du plan de déplacements urbains de Lille métropole

This paper describes the position given to road safety in Urban Travel Plans by analyzing Urban Travel Plan document from eleven cities and undertakes a more in-depth investigation of road safety in the Urban Community of Lille. These plans provide an opportunity to disseminate knowledge about road safety to the other areas of urban management. They also describe the beginning of an integration of road safety in urban planning, even if intersectoral approaches at city level have yet to be developed and even if, in the case of Lille, the division of institutional competence with regard to the management of public space still requires clarification.