EP2596486B1 - Method for improving the reliability of speed limit information for on-board systems - Google Patents

Description

The present invention relates to a method and a device for improving the reliability of speed limit indications that are communicated to motorists, including the indications that are provided by the various systems on board vehicles.

We know that, overall, road safety is in line with the respect by motorists of the speed limits that are specified on roadways. One difficulty, however, is that these limitations are sometimes distributed in a surprising way without, apparently at least for the motorist, the most drastic limitations being associated with the dangerousness of the route taken.

In addition, there has also been a proliferation of road zones for several years in which speed limits follow one another and change several times over very short distances, sometimes only a few kilometers, so that the user must, at all times, to focus on this aspect of driving, sometimes to the detriment of safety.

Moreover, the proliferation of speed control devices on both motorways and secondary roads requires drivers to have reliable information on the speed limit of the section of road on which they drive at all times. .

The motorist is assisted by various driving assistance devices that currently equip many vehicles and that indicate to him permanently and in real time the value of the maximum authorized speed of the section of road on which he is driving. circulates. Such devices, in a known manner, combine, for the most part, means of locating the vehicle, in particular by a satellite geolocation system, or GPS, with the limiting speeds associated with this location which are contained in data banks, and then inform the driver by an appropriate display. Some of these systems are able, at the request of the driver, to signal to the latter any exceeding of the speed limit by a signal, including a sound signal.

One of the major difficulties of these devices is their low level of reliability. Indeed, it is known that the databases in which the speed limit values of the road sections are recorded are particularly difficult to keep up to date and it is known that while the main highways are regularly observed, the minor axes are observed and updated much less frequently, so that it can take several months between the variation of a speed limit in the field and its update in the map of the database.

The document US 2008/0252487 discloses a method of evaluating the quality of the speed limit information contained in a database.

The present invention proposes to remedy this drawback by proposing a method making it possible to keep up to date, almost in real time, the databases containing these limit speeds of a road network with an excellent reliability, and this without it being necessary. necessary to use service vehicles for field surveys.

• prennent en compte ladite "base des vitesses" afin de sélectionner les véhicules qui, pendant une période de temps déterminée, ont parcouru au moins un tronçon déterminé,
• déterminent la vitesse maximale moyenne de circulation de ces véhicules sur ce tronçon pendant ladite période de temps,
• comparent cette vitesse maximale moyenne à la valeur limite enregistrée dans ladite "base des vitesses limite",
• évaluent la valeur de la différence entre ces deux valeurs et, si cette différence dépasse un seuil donné, engagent une procédure de contrôle sur le tronçon concerné.

The subject of the present invention is thus a method for evaluating the quality of the information contained in a database of a remote server storing the limit speed values of the various sections constituting a road network called "limit speed base", in which is recorded in a database, called "speed database", the speeds on these sections of vehicles equipped with geolocation and communication means with said remote server, characterized in that the server management means:

• take into account said "velocity base" in order to select the vehicles which, during a determined period of time, have traveled at least a determined section,
• determine the average maximum speed of movement of such vehicles on that section during the said period of time,
• compare this average maximum speed with the limit value recorded in said "speed limit database",
• evaluate the value of the difference between these two values and, if this difference exceeds a given threshold, initiate a control procedure on the section concerned.

Said threshold may consist of a given percentage of the value of the recorded speed limit.

• la figure 1 est une vue schématique d'un dispositif suivant l'invention comprenant un serveur distant et une interface embarquée,
• la figure 2 est une vue schématique d'un tronçon d'une voie routière et des segments qui composent ce dernier,
• la figure 3 est un logigramme montrant les moyens d'acquisition des vitesses à partir des véhicules,
• la figure 4 est un logigramme montrant le traitement par le serveur des informations de vitesse reçues des véhicules,
• la figure 5 est un logigramme illustrant le procédé permettant de détecter une possibilité d'erreur de la vitesse limite enregistrée sur un tronçon d'une voie routière,
• les figures 6 à 8 montrent un exemple d'interface embarquée à bord d'un véhicule dans trois séquences de fonctionnement du procédé suivant l'invention,
• la figure 9 est un logigramme illustrant le procédé conduisant à la correction de la base de donnée des vitesses limite.

An embodiment of the present invention will be described hereinafter by way of nonlimiting example, with reference to the appended drawing in which:

• the figure 1 is a schematic view of a device according to the invention comprising a remote server and an onboard interface,
• the figure 2 is a schematic view of a section of a highway and the segments that make up the highway,
• the figure 3 is a logic diagram showing the means of acquiring speeds from vehicles,
• the figure 4 is a flowchart showing the processing by the server of the speed information received from the vehicles,
• the figure 5 is a logic diagram illustrating the method for detecting a possibility of error of the speed limit recorded on a section of a roadway,
• the Figures 6 to 8 show an example of an on-board interface on a vehicle in three operating sequences of the method according to the invention,
• the figure 9 is a logic diagram illustrating the process leading to the correction of the database of limit speeds.

As shown on the figure 1 , the system according to the invention essentially uses a remote server 1 and motor vehicles which are equipped with an onboard interface 3 comprising geolocation means, in particular of GPS type, and means able to communicate these with the remote server, in particular by a network of GPRS or 3G type.

More precisely and for this purpose, the different axes of the road network are divided into sections which each represent an interval in which the value of the limit speed is the same. Each of these sections is listed by a unique number. They are themselves divided into a series of segments.

For example, it has been shown on the figure 2 a road section tr which begins at a point A where the speed goes from a value of 90 Km / h to a value of 70 Km / h and which ends in a point B where the speed goes from 70 km / h to 90 Km / h in the case of a vehicle traveling from A to B. This section tr on which the speed is limited to 70 Km / h is broken down into ten segments S ₁ , S ₂ ..., S ₁₀ . These segments integrate the geometry of the section, so that the position points that are given by the geolocation system, in particular of the GPS type, can be positioned precisely on the nearest segment S _n .

The remote server 1 comprises several databases, namely in particular a "cartographic base" 4 which contains the road network map and which, in combination with the positioning coordinates provided by the geolocation means, makes it possible to locate on a map the vehicles equipped with the system, a "base of limit speeds "5 which contains section by section the set of speed limits V _LE of the road network, a" speed base "6 intended to receive the values of the speeds V recorded during the process, and a" base of controls "7 .

As shown on the figure 1 these databases are managed in a known manner by a processor 9 to which are also connected remote communication means 11 for the communication of the server 1 with vehicles equipped with a specific interface 3.

The latter comprises remote communication means 13 with the server, in particular of the GSM type, as well as geolocation means 15, in particular of the GPS type. It comprises means for displaying visual messages by means of a screen 17 or sound messages by a loudspeaker 19. It also comprises means for sending messages to the server 1, in particular consisting of a simplified keyboard 21, the assembly being controlled by a microprocessor 23.

Under these conditions, the geolocation system 15 which is on board the vehicle periodically sends to the remote server 1, via its communication means 13, its speed and its position coordinates, and the calculation means of the server 1 are suitable, by comparison with the data stored in the "mapping database" 4, to determine on which segment S _n of which section tr the vehicle is the closest. These coordinates of the section as well as the value of the speed V of the vehicle are stored in the "speed base" 6.

The server 1, from the "speed limit base" 5 is able to establish what is the speed limit recorded V _LE for the tr section on which the vehicle is located and can thus retransmit to it, by its remote communication means 11, the speed limit registered V _LE that must observe the vehicle.

The method for controlling a database is in fact carried out in three main steps, namely a first step of acquiring the speed information during which the server 1 receives the speed information from the vehicles and classifies them in the "speed base" 6, a second step during which the server 1 detects, section by section, the possibility of errors in the speed limits recorded V _LE in the "speed limit base" 5 and a third step during from which it manages a real speed control on the sections where it detected a possibility of error.

In the first step of acquiring speed information, as shown on the flowchart of the figure 3 as soon as a valid position of the GPS is acquired, the on-board system of each vehicle in circulation periodically sends the server 1 a frame of speed information, namely the date and the time as well as the positioning in latitude and longitude and the speed V of the vehicle.

Upon receipt by the server 1, as shown on the flow chart of the figure 4 if the speed V of the vehicle is greater than a given minimum value, for example 40 Km / h, it takes into account the elements of this information frame and the geolocation parameters thereof provide it, by the consultation of the "map table" 4, the reference of the track on which the vehicle is located (for example A6), the section thereof (for example: tr section), the segment (for example: segment S ₅ ). Then the management system of the server 1 stores this information as well as the speed of the vehicle (for example: 128 Km / h), the speed limit on this section (for example: 130 Km / h), and the date (day and time). ) in the "speed base" 6.

In the second step, the server management system will implement operations that are intended to detect the possibility of errors relating to the value of the stored limit velocities V _LE . As shown on the flowchart of the figure 5 , the system operates on each of the tr sections of the "speed base" 6 which for a given period, for example a day, has been concerned.

The system aims to evaluate the average maximum velocity V _MM per section from the vehicle speeds V stored in the "base velocities" 6. The system first makes a first selection based on the recorded speed limits V _LE of each section and invalidates the speeds V lower by more than 30% to the recorded speed limit V _LE for this section. Then, it calculates the average maximum speed V _MM by calculating the mode, or the maximum speed most commonly observed, for each section and for the given period.

The system then checks whether, on the tr section concerned, it has enough measures to make them statistically valid. In other words, it checks whether, on this section, enough vehicles have circulated during said given period of time T and have had their parameters recorded in the "speed base" 6.

If this is the case, the system calculates the difference δV existing between the value of the recorded speed limit V _LE for this section in the "speed limit base" 5 and the average maximum speed V _MM of the vehicles having circulated during the period given time T on this section tr , and this after having eliminated from the calculation speeds too low, that is to say, being below a minimum value determined for this section. For example, for a stretch whose speed limit recorded V _LE is 130 Km / h will eliminate speeds below 100 km / h.

If the speed difference δV is greater than or equal to a determined threshold, the system generates a request called "real control request" for this section, and this request is stored in the "control database" 7 where it will remain until the actual control, which is the third step of the process, is performed. According to the invention, the speed threshold may in particular be constituted either by a fixed fixed value, or by a percentage X of the limit speed value already recorded V _LE , this percentage may for example be between 10% and 20%. will thus check the condition: $$\mathrm{.DELTA.V}>=\mathrm{X}\%\mathrm{.}{\mathrm{V}}_{\mathrm{THE}}$$

During the third step, the server management system 1 will verify, for the sections for which a real control request has been recorded in the "control database" 7, whether proposals for new limit speed values V _LP correspond to the values indicated V _L0 by the signs.

As explained above, it is known that the server management system 1 is able to know if a vehicle is approaching a determined tr section. Thus, according to the invention, as soon as a vehicle approaches a section for which a real control request has been recorded, the server sends to this vehicle, via its remote communication means 11 and those 13 whose vehicle is equipped, an interrogation message.

This message may be an audio type message and / or a message appearing on the screen 17 of the interface 3 of the vehicle.

Interestingly, this screen 17 can group on a concentrated surface a certain amount of information which experience has shown to be fundamental to the safety of the driver. In order to make them even more explicit, some of them can be formulated in different colors, in particular based on green for information that does not require the driver to pay particular attention or, on the contrary, based on red for information. that the driver must imperatively and immediately take into account.

As an example, we have shown figure 6 a communication interface 3 embedded in a vehicle which groups together in the same subset the screen 17 and the keyboard 21 having three buttons 21a, 21b, 21c, and which is available to the driver to receive messages from the server 1 and to emit others in the direction of it, whether or not these last messages are sent in response to server queries.

Thus, during normal operation, the system indicates in zone z1 of the screen the recorded speed limit V _LE to be observed on the road section tr where the vehicle is located, and in zone z2 located under zone z1 the reference of the road to which this section belongs. To the right of this information, in zone z3, we find the actual instantaneous speed V of the vehicle. In this normal navigation configuration, the button 21a allows the user to signal to the remote server the presence of a disturbance in the direction opposite to its own direction of movement, the button 21c allows the user to signal the presence of a disturbance in its own direction of movement, and the button 21b allows the user to signal the presence of a particular disturbance. The function of these buttons is indicated in a zone z4 of the screen located above the buttons.

According to the invention, when the server 1 has determined that a vehicle is approaching a section tr for which a real control request has been entered in the "base of the controls" 7, it checks, preferably at first, the reliability of the driver of the vehicle concerned insofar as he has in his data bank such information and, if it turns out that the driver is reliable, he then sends the vehicle an interrogation message, for example as well as represented on the figure 7 "Speed limit correct? By displaying in a zone z5 of its screen. Moreover, the management system of the interface modifies the function assigned to the buttons 21a, 21b, 21c and their new function is displayed in the zone z4.

Thus, a pressure on the button 21c on the right indicates that the speed limit observed V _LO by the driver on the traffic signs is equal to the speed limit recorded V _LE and displayed in the zone z1 of his screen, and a pressure on the left button 21a indicates that the observed speed limit V _LO is different.

In the case where the user acts on the right button and confirms that the speed limit displayed V _LE is correct the embedded system sends the remote server this response that takes into account as explained below.

In the opposite case, the management software of the onboard interface then modifies the zone z5 of its screen, as represented on the figure 8 , to display a message asking the driver to select a speed limit. It also modifies for this purpose the function assigned to the buttons 21a, 21b, 21c and the display of the zone z4 so as to enable the user to reply to the message displayed in zone z5. The meaning attributed to each of the three buttons is thus for the button 21a the value "-", for the button 21b the value "OK" and for the button 21c the value "+". Each time one of the left or right buttons is pressed, the value of the proposed limit speed V _PP, which is displayed in zone z1, is modified by respectively decremented and incremented values, for example by 10 Km / h. When the desired value is obtained, the user then presses the button 21b "OK" to validate his choice.

As shown on the flowchart of the figure 9 , on receipt of the response, the server counts in a file the responses sent by the different vehicles traveling on the same section tr and checks whether a rate of agreement has been established.

The agreement rate may be for example a minimum number of identical answers or a percentage of the answers provided by the users. As soon as the agreement rate is reached, the system updates the "speed limit database" 5 and cancels the request that was previously sent to the vehicles traveling on this section on the actual control of the value of the speed limit. . Finally, the system removes from the "control base" 7 the actual control request for the section concerned.

The interface 3 which is on board the vehicle may be, according to the invention, consisting of a device integrated therein, in particular on its dashboard, consisting of a removable device, or consisting of a specific application made available on a "smartphone" equipped with GPS tracking means.

Claims (8)

1. Method for assessing the quality of the information contained in a database (5) of a remote server (1) storing the speed limit values (V_LE) for the various sections (t_r) that make up a road network, called "speed limit base" (5) in which is stored in a database, called "speed base" (6), the speeds (V) on these sections (t_r) of vehicles equipped with geolocation means (15) and means for communicating (13) with said remote server (1), characterized in that the management means of the server:

   - take account of said "speed base" (6) in order to select the vehicles which, for a determined time period (T), have travelled at least one determined section (t_r)

   - determine the average maximum speed (V_MM) of travel of these vehicles on this section (t_r) during said time period (T),

   - compare this average maximum speed (V_MM) to the limit value (V_LE) stored in said "speed limit base" (5),

   - assess the value of the difference (δV) between these two values of average maximum speed (V_MM) and of limit value (V_LE) and, if this difference exceeds a given threshold, engage a control procedure on the section (t_r) concerned.
2. Assessment method according to Claim 1, characterized in that said threshold consists of a given percentage of the stored speed limit value (V_LE).
3. Assessment method according to Claim 1 or 2, characterized in that:

   - the management means of the remote server (1) enter into contact with the vehicles which are located approaching a section (t_r) to be controlled in order to send them a visual and/or audible message,

   - this message indicates the value of a proposed speed limit (V_LP) for said section (t_r), and asks the user of the vehicle to confirm or deny this value according to the value of the real speed limit observed (V_L0) in situ by the latter on the section (t_r),

   - once the response is given by the user using manual (21) or sound response capture means of the communication means (13) of the vehicle, the latter send to the remote server (1) this response of confirmation, of denial or of non-response,

   the remote server (1) records the latter information and stores it in storage means, notably temporary.
4. Control method according to Claim 3, characterized in that the management means of the remote server (1) store said response in temporary storage means and implement a checking phase.
5. Control method according to Claim 4, characterized in that the checking phase consists in waiting for said response to be confirmed by a number or a given percentage of identical responses.
6. Control method according to one of Claims 4 or 5, characterized in that the remote server (1) comprises a database containing the references of the vehicle users and reliability indices thereof, the checking phase consisting in taking into account the reliability indices assigned to only these users to confirm said response.
7. Control method according to Claim 6, characterized in that the reliability indices attached to the users are contained in a database and are a function of the responses supplied by the users in the past.
8. Control method according to one of Claims 5 to 7, characterized in that the checking phase is followed by the entry of said response in the "speed limit base" (5).

Images