Les objectifs de qualité urbaine et de sécurité routière dans la planification de la mobilit'e plan urbain de trafic (Brescia) et plan de déplacements urbains (Aix-en-Provence), deux visions différentes

Apart from the fact that it is of interest in itself to conduct the first comparison between Urban Travel Plans in France and Italy, this paper has the more general aim of examining a number of ideas which are shared by the scientific community, namely that urban policies and planning practices take ittle account of, or even completely ignore, road safety, the relationship between town planning and transport planning and consultation.     

Âge des conducteurs de voiture et accidents de la route: Quel risque pour les seniors ?

Increasing life expectancy and the fact that the baby boomer generation is reaching retirement age are increasing the size of the elderly population. As road users, seniors have quite specific travel behaviours, and this has an impact on accidents. This paper adopts a quantitative approach with a view to showing the specific characteristics of elderly drivers as regards travel, accidents and road risk. Towards this end it surveys a number of previous studies and takes advantage of recent data to update some of the findings of these contain. Some road risk indicators are described, and attention is paid to the methodological bias inherent in the methods employed. Our analysis shows that the presence of seniors on the roads is growing as the proportion, particularly of the women, in this group who are accustomed to driving increases. They nevertheless cover fewer kilometres than other drivers and develop compensatory strategies, for example not driving when conditions are difficult or driving more slowly than other drivers. When they have accidents they tend to be more severe because of their greater vulnerability. They have higher crash involvement at intersections as a result of detection and estimation difficulties in the driving task. The excess crash risk per kilometre driven for seniors that was observed a few years ago is tending to fall, or even disappear, if the low mileage bias is taken into account.     

Impact de la tarification,des fréquences et des temps de transfort sur les flux ferroviares dans le Bassin parisien

We have modelled trips on the Paris basin on the basis of the SNCF long-distance surveys. This modelling allows us to test the impact of pricing, journey times and train frequencies on rail travel demand. Three models have been constructed — a generation model (which computes trip production, that is to say the distribution of trips on the basis of the zones in which rail users reside), a geographical distribution model which is used to estimate the distribution of trip production on the basis of origin and destination zone, and lastly a model choice model which computes the proportion of commuting flows which takes place by rail. In this study the generation model has been partially supplied by the surveys. The distribution model takes thetrip production data output from the generation model in order to evaluate the total of rail flow on each O-D pair. This data is then used to calibrate the modal choice model.     

Quelles interactions entre les marchés de la mobilité à courte et à longue distance ?

This paper proposes a comprehensive quantitative approach to travel analysis that considers personal travel practices with regard to three travel market segments: local weekday travel, local weekend travel and long-distance travel. The first section consists of an evaluation of the overall size of these segments and demonstrates the increasing importance of long-distance travel. Each market segment and then travel as a whole are then analyzed according to individuals’ position in the life cycle, residential location and income level. Last, the roles of location and income in the creation of travel demand in the different segments are then investigated for individuals in the middle part of the life cycle. In particular, it is demonstrated that weekend and weekday travel do not compensate for one another, but there are significant interactions between both local and long-distance travel, and, in particular, residential location.     

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.     

Les systèmes de transmission sol-train état de l'art et perspectives

Intelligent transportation systems aim to provide comprehensive improvements to the efficiency and safety of transportation systems by applying new information and communication technologies. Such techniques are increasingly used for guided transport, bringing this into the domain of intelligent transportation. The functions involved in the movement of trains which were formerly performed by drivers and staff on the ground are now performed by means of fail-safe automatic devices which are controlled by transmissions between the track and the train. Ultimately, the development of intelligent transportation therefore involves total replacement of the driver, as has been the case since 1983 in the first French automatic metro, the val in Lille. This example was followed by ordival at Orly, maggaly in Lyon, the val in Toulouse finally, and most recently in October 1998, ratp line 14 in Paris, known as meteor. This paper describes voice and data track-to-train transmissions for train control command and safety purposes and also in order to satisfy the demands of passengers. The principal applications of track-to-train transmissions are covered as are the technologies employed. The increase in requirements and in the functions performed by automatic devices and the objectives of improving performance and increasing train speeds have resulted in the development of a new European train control-command system, the most advanced version of which is essentially based on track-to-train radio communications. This new system, which was principally developed for high speed train systems is being viewed with increasing interest by urban and suburban guided transport networks. At the same time, the remarkable growth to the mobile telecommunications market has led to the emergence of new needs, linked to the improvement of the services provided to passengers.     

Vieillissement et gravité des atteintes lésionnelles des victimes d’accident de la circulation routière

This study uses the road traffic accident casualty register for the Rhône Département to investigate how the risk of severe or fatal injury varies according to age and to describe the injuries that explain the severity. Two groups of road users are investigated, car occupants and pedestrians. A NISS score of nine or over is taken to indicate a severe injury. Data analysis reveals that, for both groups, the risk of severe or fatal injury increases with age. The nature and location of the injuries depend on the age and sex of the victims. With regard to severe injuries, elderly female pedestrians are susceptible to fractures of the femur (and the femoral neck) and all parts of the upper limbs. Elderly male pedestrians are mainly exposed to fractures of the femoral neck. The greater vulnerability of severely injured elderly drivers results in thoracic injuries, which are partly explained by seat–belt wearing. The main cause of death, for pedestrians of all ages and young drivers is severe head injuries. Car occupants over the age of fifty more frequently suffer from severe thoracic injuries. These findings should not, however, be allowed to conceal the differences observed in the general population for the two severity criteria we have analyzed (severe injury or death). Mortality (in relation to the general population) is highest for young car occupants, while lethality (the fatality rate amongst those injured) is highest among the elderly. For pedestrians, both mortality and lethality increase with age. These findings are also applicable to the risk of severe injury. They justify the continuation of passive safety research in order to develop protection systems that are appropriate for the characteristics of car occupants. Furthermore, they should help to increase everybody’s awareness of the vulnerability of pedestrians and stimulate the introduction of preventive measures, particularly for seniors.     

Indicateurs de comparaison de scenarios prospectifs peut-on elargir le debat sur 1' avenir de la mobilite urbaine?

La construction de scenarios prospectifs de la mobilité urbaine vise généralement a faire émerger un débat sur les évolutions tendancielles, sur les inflexions qu'il conviendrait d'y apporter et sur les strategies a promouvoir. En tenant compte du cadre législatif dans lequel s'inscrivent les procedures de planification des transports a l'échelle locale, nous avons examine dans quelle mesure les indicateurs statistiques de comparaison des scenarios pouvaient s'adapter a la prise en compte des enjeux du développement durable et faciliter l'émergence d'un débat contradictoire autour de ces enjeux. Cet article expose les options méthodologiques générales retenues et fait un certain nombre de propositions concemant le contenu et la mise en forme des indicateurs a construire, en fonction des sujets abordés et des finalites de la démarche prospective.Urban travel prospective scenarios are generally constructed in order to stimulate debate on trends, on how these could be changed for the better, and on the strategies that should be promoted. While referring to the legal framework which applies to transport planning procedures at local level, this paper examines the extent to which the statistical indicators used to compare scenarios can be adapted in order to take account of the issues associated with sustainable development and facilitate the inauguration of an open debate around them. It sets out the general methodological choices that are made and makes a number of proposals about the form and content of the indicators that should be constructed, with reference to the topics covered and the aims of the prospective approach.     

Prospective de la mobilité en Île-de-France Les apports et les limites d' une démarche économétrique

The author has used econometric equations to forecast travel by car and public transport in the Paris Region in the year 2020. The parameters of the equations were estimated on the basis of the observed trends since 1980. The technique is innovative in that it takes account of changes in structural factors (distribution of population by age, ring zone of residence and car ownership) using what are termed structural demand variables. Existing forecasts of these structural factors have been used. By applying hypotheses about changes in the remaining explanatory variables (income, transport price and supply) we have estimated traffic levels in a business as usual scenario whose sensitivity to the explanatory factors has also been tested. From this we have derived some additional indicators: network congestion, trip frequencies for each mode, travel time and aggregate quality indicators. Finally, some limits of this approach are discussed.     

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.     

La surestimation de la distance intervéhiculaire dans le brouillard

The difficulties of driving in fog are usually perceived in terms of lower sight distances and reduced ability to anticipate. However, the fall in the quality of visual information can also lead to errors in judgement by affecting the way drivers perceive their environment and their movement within it. We have conducted a series of experiments in a fog chamber and on a driving simulator, with the main aim of investigating the influence of fog on vehicle headway perception. Our results have revealed that distances are seriously overestimated in fog, and that this is likely to contribute to lower headways under such conditions, In fog an overestimation of headway between 20 and 55% was observed when vehicles were visible only as a result of their rear lights, which is the case in night-time or thick daytime fog. Under these conditions, the characteristics of vehicle lights become extremely important. Overestimation of distance becomes greater when vehicles have only one rear light instead of two, and when their two reac lights are close together. Perception of vehicle distance is therefore improved by two rear lights, placed as far apart as possible to indicate the dimensions of the vehicle. No significant overestimation of headways was found during thin or moderate daytime fog, when the vehicle outline remained visible. The results have shown the importance of the familiar size of vehicles as an indicator of distance in the situations we have investigated. They confirm the hypothesis that basic mechanisms of space perception are modified in fog.