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.     

Localisation de véhicules en milieu urbain par GSM ou radiogoniométrie

The performance of most satellite based positioning procedures for terrestrial vehicles such es des glonas or lutiltras is considerably degraded in urban areas as a result of multipath propagation phenomena and masking effects caused by bulldugs and obstacles. The study described in this paper was performed et the inrets. Transport Electronics and Signal Processing Laboratory illosn and consisted of conducting a feasibility analysis and then developing a mock up of an alternative positioning solution which when compared to existing systems offered greater availability in urban areas and a comparable level of precision. The proposed system uses two independent sensors one of which obtains its information from the public gsm cellular mobile telephone network and the other from the network of public radio transmitters. The paper describes implementation of the two techniques and the results obtained in typical radio electrical environments. An understanding of the behaviour and performance of each system will make it possible to develop algorithms to process the data from the two sensors either together or separately in order to improve the ultimate performance of the system.     

L'étalement de spectre par séquence directe Une solution pour les communications radio en milieu perturbé

The need for robots to communicate in hostile environments (such as nuclear power plants) led the cea-letl to appoly its knowledge in the field of spread spectrum. By using an innovative reception structure and a diversity system the Direct Sequence Spread Spectrum (dsss) technique is able to take advantage of the multipath phenomena where conventional radio using narrow band modulations fail. The first receivers developed in the laboratory were based on surface acoustic waves filters. Progress in microelectronics meant that these analog components could be replaced by dedicated programmable digital circuits which performed all the baseband processing. The resulting flexibility has allowed us to develop high bit rate systems (up to 10 Mbits/s). Particularly well-suited for multipath environments, this technique has potential applications in a wide variety of areas, for example indoor video monitoring track-to-train communications in metro systems and communications between the head and the rear of heavy-long trains.     

Réflexions sur le transfert méthodologique de l’analyse qualitative d’accidents de la circulation routière issue de l’étude détaillée des accidents (EDA) fran?aise aux procédures d’accidents colombiennes

Nearly 90% of the traffic accidents that occur worldwide happen in developing countries. Yet road safety remains a little-studied subject in these countries, and notably accidentology studies, which provide a wealth of information. One of the major problems in studying road accidents in developing countries lies in the lack of reliable accident data. Indeed, while the comprehensive accident analysis methodologies used in developed countries provide an understanding of the origin of accidents and accident processes, as well as making it possible to define suitable, effective actions, they require reliable and relatively detailed accident data. These methodologies are notably based on detailed accident studies (DASs) and their adaptation to the analysis of accident reports. Colombia has an infrastructure for gathering and storing traffic accident data that can be used to perform comprehensive accident analyses. This article defines the feasibility of a technology transfer (clinical accident analysis) to the Colombian equivalent of accident reports. These observations are part of a doctoral thesis prepared jointly by the IFSTTAR Accident Mechanisms Research Unit and the University of the Andes in Bogotá.     

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.     

Comparaison entre les informations visuelles données par deux types de systeème de guidage

In recent years, researchers have been working on the design of navigational aids and route guidance systems. Existing systems provide information of different types and present it in a variety of ways. Information is sometimes given as text (either written or orally by speech synthesis). Exclusively visual systems may include symbols, or even better represent landmarks with simplified icons. As yet no systems provide a representation which is analogous to the road scene. In order to assist drivers on their journey we have developed pictural information which contains photographs of landmarks with arrows showing which direction to take (pictural system). From the literature on cognitive psychology and the disciplines that relate to spatial cognition, we already know the representational importance of landmarks for persons who are unfamiliar with a location. We therefore conducted experiments to compare the effects of two types of spatial information, pictural and symbolic (just with arrows), which is communicated to individuals in the real driving situation on an unfamiliar journey. This exploratory study has provided us with some insights into the limits and constraints that apply to the use of photographs as a source of route guidance information for drivers.     

Comment les péages urbains peuvent-ils satisfaire une politique d’agglomération ?

This paper evaluates the extent to which urban road pricing schemes are able to satisfy the objectives of urban policy with regard to three frequently incompatible constraints: funding, the environment and social equity. We have devised a technical tolling system which reconciles these objectives and applied it to the case of the Lyon conurbation. We reach a number of conclusions concerning the effectiveness of different toll scenarios in terms of vehicle × kilometres travelled, travel durations, atmospheric emissions and funding. In general, achieving a simultaneous improvement in the above criteria requires at least the introduction of zonal tolls which reduce private car use by those residing in the conurbation and provide funding for alternative forms of transport.     

Mesure automatique de variables de trafic par traitement d'images application à la régulation en milieu urbain

Inductive loops are widely used for urban traffic control purposes. However, the data they provide cover too small an area to provide an accurate picture of traffic conditions at an intersection. As a result there is increasing interest in image processing techniques as these can provide more varied and more accurate data about the scene whatever the prevalling traffic, environmental and lighting conditions. This paper describes the queue length and occupancy measurement system which we have developed. We begin by outlining the constraints which are imposed by the market and the system's environment. The architecture of the system and the algorithm it uses has been specified with reference to these constraints. An account is then give of the experiments we have conducted in order to evaluate the performance of the system and an analysis of the results is presented.     

Une méthode d’analyse spatiale des espaces piétons au service d’un urbanisme orienté vers le rail ?

In recent years, the quest for a more sustainable urban planning and street design has gained importance among practitioners and researchers. An urbanism oriented towards rail is a valid alternative to the long standing practices of urban planning and street lay out based on the individual car, which have conditioned the development of cities for several decades. Among different tools that could be implemented to improve rail travel attractiveness, a radical improvement of walking conditions all along the footpaths leading to rail stations is proposed. In this paper, an observation grid as well as a set of criteria for footpath attractiveness are first proposed as a tool (or methodological approach) for a spatial diagnosis. This tool is then tested on the Carnot rail station in Saint-Etienne, a city in Eastern France. Besides the assessment itself (showing assets and challenges of the areas to be redesigned), this case study leads to proposed planning principles, in terms of recommendations meant to improve footpath quality significantly.     

Besoins en information et problèmes d'utilisation des transports ferroviaires par les personnes déficientes visuelles

This paper describes some of the findings of the biovam project, which deals with the difficulties encountered by the visually impaired when travelling on public transport, for example buses, the underground or trains. The biovam project brings together a team of researchers who are specialized in the accessibility of transport to disabled persons, mobility instructors for the visually impaired and two public transport operators, the ratp (the Paris Region Public Transport Authority) and the sncf (French National Railways). The biovam project performed a survey which identified the difficulties encountered by visually impaired travellers, and then conducted an inventory of the technical devices which could alleviate these problems. This paper pays particular attention to train travel, which differs from other modes in particular as regards frequency of use, journey duration and the nature of the infrastructure and the rolling stock. The presented findings have led to a number of recommendations and the organization of an experimental program which has renewed financial support from predit.     

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.     

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.     

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.     

Le transport ferroviaire régional de voyageurs : un processus collectif d’apprentissage

Regional passenger rail services are prevalent in France, as opposed to the more marginal role they play elsewhere in the world. It is indeed at the regional level that reforms have been successfully implemented, probably because the process was gradual and cautious. Initially in 1997, seven regions began experimenting with a decentralized system of regional passenger transportation services. By 2002, all metropolitan regions, with the exception of Corsica and Ile-de-France, were involved. Today we have reached a point where this process can be retrospectively and prospectively assessed. This article is first a retrospective assessment of the role of actors and the emerging dynamic between regional passenger rail transport supply and demand. Then, a prospective evaluation is offered since regionalization is best understood as an ongoing learning process that can be discontinuous or continuous.     

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.     

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.