EP2269180B1 - Support system providing assistance in the operation of a road network with quality of service - Google Patents

Description

The present invention relates to the field of traffic supervision systems, particularly road and highway. These systems are used by network operators to monitor traffic flows, identify incidents, intervene to correct the consequences and more generally ensure both the security of the network and the fluidity of the traffic. They generally comprise sensors for measuring the state of the traffic, means of communication to ensure the feedback of the sensor information to one or more supervision centers, said monitoring centers comprising means for filtering and displaying the information transmitted from the sensors and means for deciding the information to be communicated to the users of the network and the interventions to be carried out, said interventions being able to take the form of information to be communicated to the users by means of panels with variable messages, interventions of means specific to the operator or triggering interventions by third parties (police forces, means of rescue ...). The sensors can be magnetic loops implanted in the road networks, cameras or radars. The communication means may be wired networks or wireless communication networks. The filtering means can be more or less automated, involving an exclusive or assisted intervention of agents assigned by the network manager to supervision.

In the current state of the art, a network operator who wishes to supervise said network to ensure a given quality of service, particularly in the face of incidents, uses emergency call stations or the processing of user calls to a number special, the processing by operators of data captured by magnetic loops distributed over the network and / or images collected by cameras evenly distributed and the detection of incidents by patrols. This essentially manual and reactive treatment does not allow to easily prioritize the risk levels related to specific alarms, especially over wide networks. Consequently, it is not possible today for the operator to guarantee its users quality of service classes. reproducible as defined, in particular, by telecommunications operators.

The present invention solves this problem by providing an operating aid system for filtering and prioritizing levels.

For this purpose, the invention proposes a system for assisting the operation of a road network comprising at least two image sensors, communication means which transmit information from the image sensors to at least one data center. management of the network from which intervention commands are issued in response to alarms generated by said information, characterized in that the priorities for processing information and issuing commands are defined by the successive application of a classification function of said alarms into technical priorities of intervention commands and a function of transformation of said technical priorities by weighted quality of service criteria defined for the management of said network.

Advantageously, the system for assisting the operation of a road network according to the invention further comprises at least one orientable camera.

Advantageously, each of the image sensors and each of the orientable cameras are mounted on a mast at the edge of the road network, said mast being connected to the communication means and to at least one power supply module.

Advantageously, the communication means are constituted by a wireless communication network.

Advantageously, DAI processing is performed locally at the output of the image sensors.

Advantageously, the DAI processing is able to control the pointing of at least one orientable camera towards an incident zone. Advantageously, the DAI processing generates alarms that are transmitted to a network management center.

The invention also proposes a method of assisting the operation of a road network comprising at least two image capture steps, a step of communicating the information of the captured images to at least one network management center, d. where response commands are issued in response to alarms generated by said information, characterized in that the priorities for processing information and of issuing commands are defined by the successive application of a function for classifying said alarms into technical priorities of intervention commands and a function of transforming said technical priorities by weighted quality of service criteria defined for the management of said network.

Advantageously, the method of assisting the operation of a road network according to the invention further comprises a step of shooting by an orientable camera.

Advantageously, the method of assisting the operation of a road network according to the invention comprises a step of transmitting alarms resulting from a local processing of DAI output image sensors to a network management center .

Advantageously, said alarms are characterized by information making it possible to identify at least one of the elements chosen within the group consisting of the sensor, the channel, the type of actor, the nature of the incident and its date.

Advantageously, the method of assisting the operation of a road network according to the invention further comprises an alarm supervision step comprising a sub-step of merging the alarms with data from other sensors located on the network. and a substep of ranking the alarms according to a first priority order based on the characteristics of the incidents.

Advantageously, the characteristics of the incidents are chosen from a group comprising at least criticality indices, safety indicators, traffic status indicators, the number of alarms in a spatio-temporal zone and the duration of the alarm. In progress.

Advantageously, the supervision step further comprises a substep of modifying the first priority order according to quality of service criteria defined for the management of said network.

Advantageously, the quality of service criteria are chosen from a group comprising at least minimum viability conditions, viability reference conditions, maximum return periods at viability reference conditions, distribution and spatial control indicators. -temporal traffic, indicators of traffic disruption, indicators of the effect of the disturbances, indicators of provision of the users of the network of information on the traffic conditions. Advantageously, the supervision step further comprises a substep of extracting alarms classified in order of priority those that require immediate action to display them on the screen of a network management center operator.

Advantageously, the supervision step further comprises a substep of extracting prioritized alarms those that can be solved by a single action and another substep of performing said simple action.

Another advantage of the present invention is that the system of the invention, whose architecture is based on two sensor levels, the most numerous of which are at low cost, has a very low acquisition cost. In addition, a preferred embodiment uses wireless communications between sensors, which significantly reduces the cost of deployment, especially compared to a wired communication system. In addition, the cost of maintenance is reduced because the various elements of the system are integrated.

• La figure 1 est un schéma de l'architecture générale du système d'aide à l'exploitation d'un réseau de trafic routier selon l'invention;
• La figure 2 représente un capteur d'images dans un mode de réalisation de l'invention;
• La figure 3 est un schéma de l'architecture d'un centre de gestion du trafic dans un mode de réalisation de l'invention ;
• La figure 4 est un schéma fonctionnel des opérations d'un centre de gestion de réseau dans un mode de réalisation de l'invention ;
• La figure 5 illustre les modalités de gestion des priorités d'alarmes dans le superviseur d'alarmes dans un mode de réalisation de l'invention;
• La figure 6 représente les différents niveaux de risques définis par le gestionnaire du réseau dans un mode de réalisation de l'invention.

The invention will be better understood, its various features and advantages will emerge from the following description of several embodiments and its accompanying figures, including:

• The figure 1 is a diagram of the general architecture of the system for assisting the operation of a road traffic network according to the invention;
• The figure 2 represents an image sensor in an embodiment of the invention;
• The figure 3 is a diagram of the architecture of a traffic management center in one embodiment of the invention;
• The figure 4 is a block diagram of the operations of a network management center in one embodiment of the invention;
• The figure 5 illustrates the methods of managing the alarm priorities in the alarm supervisor in one embodiment of the invention;
• The figure 6 represents the different risk levels defined by the network manager in one embodiment of the invention.

In the remainder of the description, the abbreviations and acronyms have the meanings indicated in the table below, unless a different meaning is explicitly given to them in a particular context: Abbreviation / Acronym Meaning 3G Communication network without cellular ^3rd generation wireless ADSL Asymmetric Digital Subscriber Line or Asymmetric Digital Link BAU Emergency stop strip DAI Automatic Incident Detection CCTV Closed Circuit TeleVision or Closed Circuit Camera CAN Digital Analog Converter FME For Mobile Equipment or Connector for Mobile Equipment GPRS General Packet Radio Service or Packet Radio Service GSM Global System for Mobile Communications or Special Mobile Group IEEE or I3E Institute of Electrical and Electronics Engineers or Institute of Electrical and Electronics Engineers. IP Internet Protocol or Internet Protocol KPI Key Performance Indicator or Key Performance Indicator M2M Machine to Machine or Inter-equipment Communication PL Heavy weights PTZ Pan Tilt Zoom or Panoramic Camera RTC Switched Telephone Network SCADA Supervisory Control And Data Acquisition or Control and acquisition of monitoring data ALS Service Level Agreement or Service Level Agreement T-Factor Technical priority order TCP / IP Transmission Control Protocol / Internet Protocol or Transport and Network Layers of the Internet TMC Traffic Management Center or Traffic Management Center VL Light vehicle VMS Or PMV Variable Message Sign or Variable Message Panel VPN Virtual Private Network or Virtual Private Network Wi-Fi ™ Registered trademark of the Wireless Ethernet Compatibility Alliance to designate 802.11 wireless LANs

The figure 1 illustrates the general architecture of a system for assisting the operation of a road network 10 in one embodiment of the invention. Networks of several hundred kilometers are those for which the invention will bring the main advantages. However, we can certainly consider setting up such a system to help the operator of a smaller network. An operator may also have an operating aid system that manages several geographically distinct networks and in this case, it can advantageously equip sub-networks equipment according to the invention at lower cost. Image sensors 20 having automatic incident detection (ICD) and traffic measurement capability which will be described later are positioned along the network sections. These image sensors are advantageously arranged every 300 to 400 meters (the distance may be less in case of curved road and / or slopes and / or presence of elements obstructing the scope of the field of view (eg PMV, trees , in order to ensure, preferably, a total coverage of the road linear to be monitored.In a preferred embodiment, steerable cameras 30 are also positioned along the sections of the network but with a mesh more loose, for example every 2000 meters (each camera may be oriented and / or zoomed within 1000 meters around its point of implentation; the distance may be less if elements of the scene obstruct the field of view of the camera: PMV, trees, curvature of the road). They allow you to zoom in on areas where incidents have been detected to confirm. The different cameras are connected to a network management center 50 by a wired (RTC, ADSL, etc.) or wireless (GSM, ADSL, 3G, Wi-Fi, etc.) communication network. 40. The communication network advantageously, a wireless network, preferentially cellular. The cellular communication network is of the closed network type of machines (M2M) preferentially using the GPRS transmission mode with a TCP / IP based exchange protocol. M2M allows image sensors to transmit or receive information with one or more communication servers located in the traffic management center (s) via GPRS 900/1800 MHz protocol. : The communication server is interconnected with the internet by the mobile operator. The communication server is connected via the internet. VPN communication is established between the different elements of the system.

Several levels of management centers may be provided, especially in the case where the manager operates several networks. One level can handle some of the alarms and at least one second level can handle other alarms and coordinate several first level management centers. A type of management center is described later. A management center can send messages to be displayed on variable message boards (PMV or VMS) 60. The messages contain traffic information intended for network users and possibly instructions for deviating traffic or speed to be respected. A management center may also send instructions or requests for intervention to teams of the operator provided for this purpose or to services not related to the operator but responsible for public service missions (police, gendarmerie, health services. ..).

The figure 2 represents an image sensor with DAI features. The sensor is preferably mounted on a steel mast from a height preferential of 12 meters. The mast must have sufficient rigidity to limit the vibrations and displacement due to the wind in particular. The sensor is advantageously placed in the upper part of the mast by means of its fixing device. The sensor is a camera of the intelligent camera type, that is to say carrying calculating capacities allowing the execution of video DAI software and traffic measurements such as those provided by the applicant (MediaRoad ™ / VisioPad ™). / MediaTD ™) some of whose functions are described later. The camera can be of the CanCam type provided by Feith Sensor to Image GmbH. The camera is placed in a protective waterproof camera housing of the IP66 type and is fixed to the mast using the usual fastening devices. The camera is connected via its RS-232 output to a GPRS modem preferentially of the MC35i type: GPRS class 4 modem, dual 900/1800 from Siemens. An M2M antenna is positioned, normally at the top of the mast (GPRS 900/1800 Antenna with FME connector). It can be envisaged to group the sensors 20 into a local network supporting a suitable protocol of the Wi-Fi, IEEE 802.15.4 (Zigbee) or meshed network type. The antenna will then be different. In this case, a network node will be positioned on the mast of one of the steerable cameras 30 and the antenna of this mast will allow communications to the chosen network management center. An architectural study must be done on a case-by-case basis to determine what is the optimal solution in cost efficiency given the surrounding topology. The mast must be powered. Advantageously, a set of batteries / solar panels is provided for each of the masts and ensures the energy autonomy of the sensor / antenna or mobile camera device. An example of solar module (solar panels) proposed is manufactured by the French company Photowatt, for example the model MP1100 is PW6-100 type. An example of a proposed battery model are manufactured by the German company BANNER. A stationary battery model the proposed PzS Solar is the Type 6 PzS 690. In addition to the solar modules and batteries the device is advantageously equipped with a voltage regulator manufactured by the German company STECA, The model RS3431 series regulator proposed is the Type PR3030. The batteries and the regulator are placed at the foot of the mast in a battery box of the Big Box pallet box type high density polyethylene (HDPE),

Each image sensor or elementary DAI point continuously analyzes the scene and produces an alarm in the event of an incident. An incident is defined as an event occurring unexpectedly and likely to disrupt the safety or progression of vehicles. It may require intervention by the operator and / or the driver of the vehicle. The Citilog video DAI software (MediaRoad or VisioPad) analyzes the scene captured by the video camera at a rate of 5 frames per second. The presence of vehicles is detected by double comparison between the current image, the previous image and a reference image stored at the initialization of the sensor. Vehicles are identified and marked by filters based on typical form factors (car, truck, motorcycle, pedestrian ...). A tracking algorithm allows the tracking of the marked object through the sequence of images, the analysis of its motion and the construction of the spatio-temporal trajectory of the object. The algorithm makes it possible to ensure the continuity of the tracking even in the presence of temporary masking. The algorithmic interpretation of the movement and displacements makes it possible to detect, classify and position the incidents: vehicles stopped in fluid traffic or in bottling, slowing down , slow vehicle, misinterpretation, etc. Specific treatments are advantageously applied to reduce the false alarm rate (tracking lock on detected movements, elimination of background noise, filtering of weather conditions, self-learning of previous false alarms ...)

• L'identifiant de la caméra (qui indique la position sur le linéaire)
• La voie concernée (BAU, voie rapide, voie lente, etc.) et la position dans la voie.
• Le type de l'acteur : piétons, véhicules (éventuellement qualifié : VL / PL / Transport collectif / transport matière dangereuse), débris sur la voie ;
• La nature de l'incident : arrêt, mouvement lent dans un flux, mouvement rapide dans un flux, arrêt prolongé dans une congestion, etc.
• La date (h:m:s) de début d'incident (T0).

In addition to the DAI analysis, the elementary point may be required to perform traffic measurements of the type: counting, speed, occupancy rate, inter-vehicular time, etc. The measurements are aggregated and sent to the supervisor at regular intervals. The preferred sending frequency is configurable and can be set advantageously at 6 minutes. From these measurements are calculated for each portion of road a global security indicator and the current traffic status. When an incident occurs, an alarm is automatically generated. Each alarm is characterized by:

• The identifier of the camera (which indicates the position on the linear)
• The channel concerned (BAU, fast lane, slow lane, etc.) and the position in the lane.
• The type of actor: pedestrians, vehicles (possibly qualified: VL / PL / Collective transport / dangerous goods transport), debris on the track;
• The nature of the incident: stop, slow motion in a stream, fast motion in a stream, prolonged stop in congestion, etc.
• The date (h: m: s) of the beginning of the incident (T0).

At T0 + ΔTn, (ΔTn being configurable according to the type and nature of the alarm) the alarm is sent to the supervisor located in the traffic management center (via M2M or any other means of communication). The time TN = T0 + ΔTn is added to the characteristics of the alarm. An image or clip is sent simultaneously and associated with the alarm. At the end of the incident (return to normal) the DAI point informs the supervisor (acknowledgment). On request, the image flow can be transmitted to the supervisor for real-time visualization.

PTZ orientable cameras 30, present in a preferred embodiment of the invention, are mounted on masts of the same type as those on which the image sensors are mounted. These masts, or some of them, are also preferably equipped with an antenna, a modem, batteries and solar panels of the same type as those coupled to the image sensors. However, they have a higher height to cover a wider area and a geometry adapted to said upper height and the higher weight of the equipment. The PTZ cameras have the following characteristics: it is a CCTV camera equipped with an objective with zoomed motorized x18 and remotely controllable. The camera must be connected in IP flow preferably MPEG4 (BOSCH AutoDome 500i series suspended outside). It must be placed in an IP66 waterproof box and secured with these standard mast attachments. The cameras are oriented by automatic or manual control either from the DAI sensors of the zone or from the traffic management center. The images they send to the management center validate the information received from the DAI sensors by zooming in on part of the area where the incident that triggered the alarm occurred.

The figure 3 represents the architecture of a management center in one embodiment of the invention. The signals received from the DAI sensors and the PTZ cameras are stored on a communication and alarm supervision server. The communication and alarm supervision server is a standard industrial PC integrated into a chassis. It is connected to image sensors, mobile cameras and traffic management processing software from the control center or SCANDA. It is equipped with specialized software, such as those marketed by the plaintiff which performs the following tasks: communication with image sensors and mobile cameras, centralization of alarms, video clips and traffic measurements, supervision of alarms (such as as defined below), technical supervision, configuration and maintenance of the system, communication with the SCADA of the traffic management center, communication with the CCTV system of the traffic management center, ie control of a video switch. Other types of sensors can also be connected to the management center and provide measures for it: induction loops installed in the roadway of the network, especially at particular points such as access or exit ramps and tolls; weather sensors (anemometers, fog or rain indicators ...). A traffic management center according to the invention will advantageously include an image wall for viewing the ascent of the DAI sensors and PTZ cameras. It also includes workstations assigned to operators who process the alarms. The various processing modules above implanted in a management center according to an embodiment of the invention are advantageously interconnected by a local network using a standard communication protocol such as the IP protocol.

The figure 4 is a block diagram of the operations of a network management center in one embodiment of the invention. The first two input processes of the management procedure will be detailed in the rest of the description: alarm processing with grouping by event and calculation of technical priorities; the alignment of priorities with the service level objectives of the operation. If the alarm has no effect, given the service level objectives, the alarm can be displayed on a secondary screen for a configurable duration and the alarm will remain without any other effect. If the alarm is to be processed, then one determines its level of criticality according to which the action of the operator must be immediate or not. If an immediate action is required, the alarm is immediately presented to the operator, possibly with the image of one of the DAI sensors concerned. In addition, the closest orientable camera is directed to the alarm and the real time image of said camera is presented to the operator. If an immediate action by the operator is not required, it is stored in a queue to be displayed when possible on the one hand on a main screen (for the highest priority level) and on the other hand on a secondary screen (for the alarms of the second priority group). The operator can then select one of the alarms and direct the nearest mobile camera to the area of the incident that triggered the alarm to display a real time image. If the alarm requires a simple action, such as displaying a message on a PMV, that action can be triggered automatically. It is then displayed on the main screen of the operator at the same time as the triggered and acknowledged action. If the action required by the procedures established by the operator is not simple enough to be triggered automatically, the software proposes a recommendation that is displayed on the operator's main screen. In any case, the operator can intervene at any moment in the chain of decision, in particular to modify the order of priority of the alarms. It may be advantageous to have two categories of operators, one to deal with low alarm levels and another to deal with the highest alarm levels. This reduces the risk of seeing unprocessed priority alarms.

The figure 5 illustrates the methods of managing the alarm priorities in the alarm supervisor in one embodiment of the invention. The priority management of alarms constitutes the software core of the system for assisting the operation of a road network according to the invention. The decision support software realizes a grouping of the alarms by event and then carries out a classification in order of priority taking into account data coming from several kinds of sensors (DAI, orientable cameras, loops in the ground, other mode of counting of flow of vehicles, weather ...).

At regular intervals, the alarm supervisor receives the traffic measurements from either the DAI sensors or other traffic measurement sensors (magnetic loops, radar, etc.). When an incident is detected by one of the DAI sensors, the supervisor receives this alarm. The alarm is then processed by the system for processing and prioritizing alarms. According to the result of said processing, the alarms or events (if the alarm is part of a coherent set of alarms coming from the same spatio-temporal space) are classified in order of technical priority defined from the level of risk that presents an incident, which is called T-Factor. The T-Factor is calculated for each of the sensors with temporal and spatial correlation. It can also be calculated in aggregate on a set of sensors covering a segment of the highway. The T-Factor can be defined for example on a scale of 1 to 5. The classification of incidents on this scale depends on the past practice of the operator, his forecasts, especially on the future performance of his means of intervention and best practices from other operators. The order of priority is based on criticality indices, instantaneous safety and traffic status indicators, the number of alarms involved in an event and the duration of the alarm. These elements are detailed in the following description.

Definite a priori criticality indices that are function of the environment function: for each constituent element of an alarm, a criticality index is assigned according to the security problem and the mobility problem. Criticality according to the security problem corresponds for example to the risk of aggravation of an incident in terms of mortality or severity of injuries, or risk of over-accident. Thus a tunnel alarm is much more critical than an outdoor alarm because an incident in a confined space can have much faster and more serious consequences. As another example, an alarm in the middle of the track is much more critical than on a BAU because the risk of over-accident by rear collision is much greater. Criticality in terms of mobility refers to the potential impact of the incident on the flow of traffic and the time necessary to re-establish the conditions of use of the track as close as possible to the normal situation.

The a priori indices of criticality of security and mobility are defined by the network operator but there are commonly accepted values which are given by the following tables:
- For each camera (tunnel, bridge, interchange, linear, number of lanes etc.) Example (1 lowest value, 5 highest) security Mobility Tunnel 5 3 Bridge 4 3 exchanger 3 2 Linear (2 ways with BAU) 1 1 Linear (2 channels without BAU) 3 3
- For each type of pathway (BAU, insertion path, slow lane, expressway, refuge, etc.) Example (1 lowest value, 5 highest) security Mobility BAU 1 1 Insertion path 3 3 Refuge 1 1 Slow way 4 3
- For each actor (pedestrian, vehicle, VL, PL, public transport, transport of hazardous material, etc.) Example (1 lowest value, 5 highest) security Mobility Pedestrian 2 1 VL 3 2 PL 4 3 Public transport 5 3 Hazardous material 5 5 ...
- For each type of incident (presence, stop, misinterpretation, abnormal movement in a flow); Example (1 lowest value, 5 highest) security Mobility Presence 2 2 misinterpretation 4 3 Stop 3 4 Abnormal movement 1 1 ...

• un indicateur de sécurité global basé sur les mesures de circulation voie entière qui peut par exemple être basé sur un modèle prédictif de situations à risque d'accident fondé notamment sur des dépassements de seuils de vitesse pour une densité de trafic donnée (Voir par exemple Jean-Marc Morin - Cédric Perot, « Un indicateur temps réel de sécurité des écoulements Congrès International ATEC-ITS France, 2008 )
• Un indicateur de mobilité globale ou état de Trafic ; l'état du trafic à un instant donné définit l'impact potentiel d'un incident d'un type donné sur le trafic et donc la mobilité ; quatres états de trafic sont définits par les centre d'information routière T1 fluide, T2 dense, T3 saturé, T4 bloqué.

The instant indicators on the security and the state of the traffic are calculated according to the measurements of traffic:

• a global safety indicator based on full-track traffic measurements, which may for example be based on a predictive model of accident-risk situations based in particular on exceeding speed thresholds for a given traffic density (see, for example, Jean -Marc Morin - Cédric Perot, "A real-time indicator of flow safety International Congress ATEC-ITS France, 2008 )
• An indicator of global mobility or traffic status; the state of the traffic at a given moment defines the potential impact of an incident of a given type on traffic and therefore mobility; Four traffic states are defined by the traffic information center T1 fluid, T2 dense, T3 saturated, T4 blocked.

The order of priority also depends on the number of alarms involved in an event, said event being defined by a set of alarms of the same nature (or corresponding to a predetermined scenario) occurring in a predetermined time and space interval ( step by step, ie by grouping the n-order spatial connectivity alarms, n being the number of upstream or downstream cameras and preferably equal to 1 and / or temporal grouping of the temporal connectivity alarms Δt , Where Δt is the time difference between 2 alarms Example 1: a vehicle in the opposite direction will pass from cameras to cameras in a given time interval, all these alarms are grouped together to form the event against direction. : In case of chain collisions 1 alarm will be raised for the ^1st stopped vehicle, then for the second, then for the third one as long as the time interval between 2 successive alarms does not exceed the threshold predetermined temporal connectivity Δt);

The duration of the current alarm (or event) is also in the order of priority.

The prioritization alarm algorithm (translated in the T-Factors scale) uses known classification techniques, especially for power plant management such as fuzzy logic, neural networks, multi-agent systems , expert system or other techniques. These techniques have in common to rely on a calibration. Operationally, this calibration will be performed by inputting alarm records to the classification software, testing the result in terms of the distribution of alarms in the classes, and adjusting the input weights used by most of these techniques to arrive at the classification software. on a classification scale that corresponds to the priorities of experience. An exemplary embodiment may use one of the algorithms proposed by Kyrykides (A Next Generation Alarm Processing Algorithm Incorporating Recommendations and Decisions on Wide Area Control, I3E, 2007). The priority of each alarm is recalculated at regular time intervals.

The figure 6 represents the different risk levels defined by the network manager in one embodiment of the invention and illustrates how T-Factors are defined which define an order of priority Alarm processing technique to a "commercial" priority order according to the quality of service levels specified by the network operator.

The notion of quality of service can be defined contractually between an operator and its customers, the non-respect of the contractual commitments (Service Level Agreement or SLA) measured by key performance indicators (KPI) can trigger the payment of penalties by the operator to customers who are victims of these unfulfilled commitments. The concept of quality of service is widespread in the world of telecommunications. It has not yet been generalized to other types of networks, including road networks or only partially. But the same concepts are transposable.

• le client est le principal bénéficiaire de la qualité de service, mais il n'est pas le seul,
• celui-ci, pour des raisons diverses, peut modifier sa perception de la qualité,
• la définition de la qualité s'oppose à la conception ancienne de produit de haute performance : c'est la conformité aux besoins réels de l'utilisateur, qu'il est préférable de lui faire exprimer, qui est recherchée et non une approche théorique d'une qualité définie de manière abstraite et absolue.
• un service de coût trop élevé ne peut satisfaire l'utilisateur : on ne peut donc dissocier le coût de la qualité.

Quality of service can be defined as the capacity of a product or service, to satisfy the potential or expressed needs of the customers, or more broadly the beneficiaries of the product or service. Behind this definition, some further clarification is needed:

• the customer is the main beneficiary of the quality of service, but he is not alone,
• the latter, for various reasons, may change his perception of quality,
• the definition of quality is opposed to the old design of high-performance product: it is the conformity with the real needs of the user, that it is preferable to make him express, which is sought after and not a theoretical approach of a quality defined in an abstract and absolute way.
• a service of too high cost can not satisfy the user: we can not therefore dissociate the cost of quality.

• les usagers, utilisateurs directs de la route,
• les bénéficiaires extérieurs, parmi lesquels on trouve en particulier les riverains, mais aussi, si l'on se place du point de vue de l'aménagement et de l'équilibre des territoires, l'ensemble des contribuables, et les élus,
• les maîtres d'ouvrages, pour lesquels la route est construite, qui ont en charge la définition du parti d'aménagement et des spécifications techniques de la route, et qui doivent assurer le financement de cette dernière, avec éventuellement la participation de co-financeurs,
• les gestionnaires, chargés de l'exploitation et de l'entretien de la route, y compris la police.

In the case of a motorway network, additional considerations must be taken into account. The road is not an ordinary product. The creation of a road object is usually the result of a complex process in which the political dimensions of spatial planning, socio-economics and environmental protection often take precedence, in the upstream phases of design, on the purely technical considerations of defining the intrinsic characteristics of the object. Moreover, if the term "customer" is not very well adapted to the road object, the Reduction of the beneficiaries of the quality of the road to the users alone is also unsatisfactory. The beneficiaries taken into account in the assessment of the quality of service are more generally:

• users, direct users of the road,
• the external beneficiaries, among whom we find in particular the local residents, but also, if one considers from the point of view of the planning and the balance of the territories, all the taxpayers, and the elected ones,
• owners, for whom the road is built, who are in charge of the definition of the planning party and the technical specifications of the road, and who must ensure the financing of the latter, possibly with the participation of co-financers ,
• managers responsible for the operation and maintenance of the road, including the police.

• le maintien de la viabilité qui recouvre l'ensemble des interventions sur le terrain destinées, en cas de perturbations, à maintenir ou rétablir des conditions d'utilisation de la voie au plus proche de la situation normale ;
• la gestion du trafic qui recouvre l'ensemble des dispositions visant, dans le cadre d'objectifs prédéfinis, à répartir et à contrôler les flux de trafic dans le temps et dans l'espace, afin d'éviter l'apparition des perturbations ou d'en atténuer les effets ;
• l'aide au déplacement qui recouvre l'ensemble des dispositions visant à diffuser, par un moyen ou par un autre, toute information prévisionnelle ou actuelle sur les conditions de circulation ; son objectif général est la sécurité et le confort de l'usager.

Whatever their reasons for moving (professionals, home - work, leisure), users expect a constant level of service from road managers. They aspire to a reinforcement of the road safety and accept badly that the good progress of their displacements is disrupted by traffic hazards. It is therefore the responsibility of the road managers to act to minimize the effects of the disturbances. They must regularly monitor what is happening on the network to identify events, situations or degradations that could affect the safety of users and the normal flow of traffic. The operation of the road is therefore focused on the management of events (disturbances requiring urgent intervention, random phenomena, monitoring of dynamic equipment, etc.). It ensures that the route performs its function of traffic flow, with reference to a given level of service, likely to define a contractual or quasi-contractual commitment, as in the world of telecomminications or other areas of service. The operation of the road therefore includes all the actions intended to ensure the smooth running of a road and comprises 3 main areas of activity:

• the maintenance of viability, which covers all field interventions intended, in the event of disturbances, to maintain or restore conditions of use of the track as close as possible to the normal situation;
• traffic management which covers all the provisions aimed, within the framework of pre-defined objectives, of distributing and controlling traffic flows in time and space, in order to avoid the appearance of disturbances or mitigate the effects;
• travel assistance covering all provisions intended to disseminate, by one means or another, any forecast or current information on traffic conditions; its general objective is the safety and comfort of the user.

The notion of a service level results from the fact that a user of the road can be sensitive to several factors such as, in particular, the safety, the layout and the surface condition of the road, the legibility of the route indications, the fluidity of traffic, the availability in all seasons, the approval of the course ... The level of quality of service is the minimum percentage of achievement fixed by the client on the parameters above. The set of service levels defines for the manager the minimum SLA goal. For example, the Dictionary of Road Maintenance (Volume 4, May 1999) provides a definition of winter service quality for a road: a service level of C1 to C4 (from highest to highest). bottom) is assigned to a route based on its socio-economic importance. It is defined by a triplet (minimum condition, reference condition, return duration) declined according to the schedules (day, night) and in the most difficult conditions, which are normally those of the winter service. The minimum condition is that below which it is not acceptable to descend under any circumstance (C2, C3 or C4 depending on the importance of the link). The reference condition is that of normal non-incident service. The acceptable level depends on the usual meteorological conditions (mild or harsh climate). The return period is the period required to return to the reference condition; it is the theoretical maximum duration of the winter-induced parturbation on road traffic beyond its own manifestation.

An ICD system is one of the major building blocks necessary to ensure that SLA objectives are met.

DAI (especially video) is an operating aid system. In aims to detect and locate any event that is likely to disrupt the safety or progression of vehicles (incident). In the absence of an ICD system, these incidents are reported back to the operator through various tools: patrol officers, emergency call network, police force, call of users via the mobile telephone network. The advantage of an ICD system lies in the speed and completeness of the incidents that such a system can detect. Conventional systems use a series of electromagnetic loops embedded in the roadway. An algorithm that operates on certain parameters (occupancy rate, flow rate, speed) detects discontinuities in the flow of flows from an incident. A video ICD system can also detect abnormal vehicle stops or pedestrian movements. As such a video DAI system impacts the quality of service of a given network because it allows a greater responsiveness of the operator. It notably makes it possible to improve the quality of the service offered according to the two groups of KPIs useful for defining the quality of service of a motorway network, namely the group of safety indicators and the group of mobility indicators.

• o de réagir plus vite sur l'ensemble du linéaire (ce qui peut avoir pour conséquence la diminution de la sévérité des blessures en cas d'accident corporel ou la diminution du risque d'aggravation de l'incident) ;
• o d'avoir une réponse adaptée sur chaque incident grâce à l'image vidéo ;
• o de diminuer le risque de sur-accident en informant au plus vite les automobilistes par des moyens tels que : les panneaux à messages variables, la radio, la mise en place de balisage spécifique, etc.

A shorter detection time of the incidents, accompanied by a video image of the incident will allow:

• o to react faster on the entire linear (which may result in a reduction in the severity of injuries in the event of a bodily injury or a reduction in the risk of an aggravation of the incident);
• o have an adapted response on each incident thanks to the video image;
• o to reduce the risk of over-accidents by informing drivers as quickly as possible by means such as: variable message signs, radio, setting up specific signs, etc.

Traffic safety is usually measured by the number of accidents, the number of accidents, the number of fatalities, the number of injuries, the severity of injuries. The performance of the operation will be appreciated according to the time of detection of the incidents, and the time of intervention. The latter clearly has a direct impact on the severity of the injuries and the number of possible deaths. An analysis of statistics in France shows a direct link between the response time and the mortality due to an accident: a reduction of 25% in the response time reduces the number of deaths by 8%. And a reduction of 20 minutes to 10 minutes of said delay can allow to divide by 4 the number of deaths. Mobility is based on a definition of pre-incident traffic status. Four states are generally considered: a fluid state (T1), a dense state (T2), a saturated state (T3) and a blocked state (T4). The extent to which an incident can disrupt the progress of other vehicles is then analyzed. A shorter detection time will allow it to be "resorbed" more quickly and consequently to minimize the impact of this on the flow of traffic: for example, it is generally accepted that the delay over time incident-induced course is proportional to the square of the duration of the incident. In addition, an incident causes a drag effect: for each minute of blockage of a traffic lane of a highway at a rush hour, four minutes of travel time delay are induced after the end of the incident. On the other hand, if there is an operating aid system, motorists arriving in the area can be warned upstream which allows some of them to opt for another route.

The objective of the operation is to increase the reliability of the route, that is to say to minimize the impact on traffic flow of non-recurring events such as incidents. It is therefore a question of reducing the time necessary to return to a normal flow situation, in particular by improving the time of detection of the incidents.

Alarm management plays an important role in achieving this goal. The probability of having to deal simultaneously with a large number of alarms is all the greater as, on the one hand, the number of operators is reduced, and on the other hand the length of the linear highway to be monitored is large. This potentially large number of alarms can overwhelm the operator in charge of processing them. The time required for the operators to understand the whole of the situation (s) may lead to additional processing time and consequently to the quality of the service offered. The need is therefore to have an alarm management system allowing on the one hand to reduce the number of alarms seen by the operator, and to affect other share an alarm processing priority to ensure that decisions are made in line with service quality objectives.

Thus, we can move from a set of technical priority values, the T-Factors, to "commercial" or contractual priority values, represented by the KPIs.

• De la réglementation en vigueur
• De la topographie du linéaire autoroutier
• Des moyens de l'exploitation (dépenses opérationnelles; investissements)
• Du personnel disponible.

The technical priority levels are transformed according to the perceptions of the risks of each motorway operation and the service level objectives of the operation. The perception of risk depends in particular on:

• Current regulations
• From the topography of the linear highway
• Operating resources (operating expenses, investments)
• Staff available.

A transformation function is therefore applied to the T-Factor in coherence with the operator's policy and in particular to be in agreement with its quality of service objectives defined by a positioning on scales for each of the KPIs. The transformation function makes it possible to go from a T-Factor level to the risk level, which is a function of the percentages of implementation of the KPIs corresponding to the perceptions of the risks of each motorway operation and the service level objectives of the service. exploitation: $$\mathrm{Risk\; level}\mathrm{=}\mathrm{T}\mathrm{-}{\mathrm{Factor}}_{\mathrm{normalized}}\mathrm{x}\left({\mathrm{\alpha }}_{\mathrm{1}}\mathrm{.}\mathrm{\%}{\mathrm{REIT}}_{\mathrm{1}}\mathrm{+}{\mathrm{\alpha }}_{\mathrm{2}}\mathrm{.}\mathrm{\%}{\mathrm{REIT}}_{\mathrm{2}}\mathrm{+}\mathrm{...}\mathrm{+}{\mathrm{\alpha }}_{\mathrm{not}}\mathrm{.}\mathrm{\%}{\mathrm{REIT}}_{\mathrm{not}}\right)$$

• T-Factor_Normalisé : le T-Factor normalisé entre 0 et 1 tel que 0 corresponde à la valeur la plus élevé de risque technique
• %KPI_n: le pourcentage de réalisation du KPI_n
• α_1... α_n les coefficients de pondération affectée à chaque perception de risque propre ou objectif de niveau de service. Les coefficients sont choisis de telle sorte que la somme pondérée des pourcentages de KPI soit comprise en 0 et 100. 100 correspondant à des objectifs complètements atteints.

With:

• T-Factor _Normalized : T-Factor normalized between 0 and 1 such that 0 corresponds to the highest value of technical risk
• % KPI _n : the percentage of realization of the KPI _n
• α _{1 ...} α _n the weighting coefficients assigned to each perception of own risk or level of service objective. The coefficients are chosen so that the weighted sum of the percentages of KPI is between 0 and 100. 100 corresponding to objectives completely achieved.

As regards the level of risk, it is possible, as illustrated on figure 6 define six classes of KPIs according to the alarm level: no alarm; low level alarm; attention required ; level A alarm; level B alarm; maximum alarm.

The operator can choose to view an alarm or event by calling either the real time image of the DAI sensor or that of the PTZ camera closest to the alarm or event. In the case of this second chjoix, it is automatically activated so as to point to the area concerned. The image of the PTZ camera is presented to the operator. All alarms with thumbnails or associated clips are stored in a database for later analysis and possibly performance measurement.

The examples described above are given by way of illustration of embodiments of the invention. They in no way limit the scope of the invention which is defined by the following claims.

Claims (17)

1. A system for assisting in the use of a road network (10), comprising at least two image sensors (20), (30), communication means (40) that transmit information from said image sensors (20), (30) to at least one network management centre (50) from which intervention commands are transmitted in response to alarms generated by said information, characterised in that the priorities for processing the information and for transmitting the commands are defined by the successive application of a function for ranking said alarms by technical priorities of intervention commands and a function for transforming said technical priorities by weighted quality of service criteria defined for the management of said network.
2. The system for assisting in the use of a road network according to claim 1, characterised in that it further comprises at least one steerable camera (30).
3. The system for assisting in the use of a road network according to claim 2, characterised in that each of said image sensors (20) and each of said steerable cameras (30) is mounted on a mast by the side of said road network (10), said mast being connected to said communication means (40) and to at least one power supply module.
4. The system for assisting in the use of a road network according to claim 1, characterised in that said communication means (40) are constituted by a wireless communication network.
5. The system for assisting in the use of a road network according to claim 1, characterised in that automatic incident detection (DAI) processing is carried out locally at the output of said image sensors (20).
6. The system for assisting in the use of a road network according to claims 2 and 5, characterised in that said automatic incident detection (DAI) processing is designed to control the aiming of at least one steerable camera (30) toward an incident zone.
7. The system for assisting in the use of a road network according to claim 5, characterised in that said automatic incident detection (DAI) processing generates alarms that are transmitted to a network management centre (50).
8. A method for assisting in the use of a road network comprising at least two steps of capturing images, a step of communicating information from said captured images to at least one network management centre from which intervention commands are transmitted in response to alarms generated by said information, characterised in that the priorities for processing the information and for transmitting commands are defined by the successive application of a function for ranking said alarms by technical priorities of intervention commands and a function for transforming said technical priorities by weighted quality of service criteria defined for the management of said network.
9. The method for assisting in the use of a road network according to claim 8, characterised in that it further comprises a step of capturing images using a steerable camera.
10. The method for assisting in the use of a road network according to claim 8, characterised in that it comprises a step of transmitting alarms coming from local automatic incident detection (DAI) processing at the output of said image sensors to a network management centre.
11. The method for assisting in the use of a road network according to claim 10, characterised in that said alarms are characterised by information allowing the identification of at least one of the elements selected from the group consisting of the sensor, the channel, the subject type, the nature of the incident and its date.
12. The method for assisting in the use of a road network according to claim 10, characterised in that it further comprises a step of monitoring alarms comprising a sub-step of combining alarms with data coming from other sensors located on the network and a sub-step of ranking alarms in a first order of priority established as a function of the characteristics of the incidents.
13. The method for assisting in the use of a road network according to claim 12, characterised in that the characteristics of the incidents are selected from a group comprising at least criticality indices, safety indicators, traffic status indicators, the number of alarms in a space-time zone and the duration of the current alarm.
14. The method for assisting in the use of a road network according to claim 12, characterised in that the monitoring step further comprises a sub-step that consists in modifying the first order of priority as a function of quality of service criteria defined for the management of said network.
15. The method for assisting in the use of a road network according to claim 14, characterised in that the quality of service criteria are selected from a group comprising at least minimum viability conditions, reference viability conditions, maximum durations for returning to reference viability conditions, indicators for space-time distribution and control of the traffic, traffic disruption indicators, indicators of the effects of disruptions, indicators for providing network users with information relating to traffic conditions.
16. The method for assisting in the use of a road network according to claim 14, characterised in that the monitoring step further comprises a sub-step that consists in extracting from the alarms ranked in order of priority those alarms that require immediate action, in order to display them on the screen of an operator in the network management centre.
17. The method for assisting in the use of a road network according to claim 14, characterised in that the monitoring step further comprises a sub-step that consists in extracting from the alarms ranked in order of priority those alarms that can be resolved by a simple action and a further sub-step that consists in executing said simple action.

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