WO2005098780A1

WO2005098780A1 - Method of obtaining road traffic situation using mobile telephony installation

Info

Publication number: WO2005098780A1
Application number: PCT/EP2004/003341
Authority: WO
Inventors: Mihaescu Zoia; Valeriu Cirpanu
Original assignee: S.C. M-Zone Srl
Priority date: 2004-03-30
Filing date: 2004-03-30
Publication date: 2005-10-20

Abstract

Method of obtaining in real time information on the road traffic situation in a road network, the method comprising collecting repeatedly position coordinate data from selected mobile stations on board of vehicles participating in the traffic to be observed and being included in a position detection system, which coordinate data are determined by the position detection systems and are transmitted via mobile telephony to a traffic data base operatively connected to a surveying server and to base stations of the mobile telephone system, wherein the coordinate data identifying pre-selected control areas of the traffic network are stored in the data base; that the coordinate data identifying one of the control areas, i.e. the one wherein an observed one of the mobile stations is positioned, is transmitted via mobile telephony to the respective mobile station where they are temporarily stored; that the single mobile station which in time intervals determines its position coordinates detects the occurrence of coming to and passing the border of the respective control area toward an adjacent control area, whereupon data identifying this adjacent control area are transmitted via mobile telephony to the surveying server which presents the identification of the control area to the data base where it is memorized along with a time index for further evaluation, and transmits to the respective mobile station data updating in the mobile station the temporarily stored coordinate data of that adjacent control area to then constitute a new control area for the same mobile station.

Description

METHOD OF OBTAINING ROAD TRAFFIC SITUATION USING MOBILE TELEPHONY INSTALLATION

The invention refers to a method of obtaining, in real time, information on the road traffic situation in a road network, the method comprising repeatedly collecting position coordinate data from selected mobile stations on board of vehicles participating in the traffic to be observed and being included in a position detection system, which coordinate data are determined by the position detection systems and are transmitted via mobile telephony to a traffic data base operatively connected to a server which constitutes a service centre for road traffic surveillance, in short a surveying server, and to base stations of the mobile telephone system.

It is known to collect data about the road traffic situation in a road network and to provide statistics, subscribers or participants in the traffic with the necessary information. It is also known to process the traffic data so as to offer services for path optimisation or transport time calculation, for which services, the first supposition is to collect the information on the road traffic situation. It is know e.g. from US-A-6012012 both, to collect the information and to supply the resulting information, via mobile telephony. A suitable percentage of participants in the traffic transmit, via mobile stations, e.g. GSM terminals, position data and possibly also other information to a base installation were the incoming data are processed and the results are sent to selected terminals and/or to third parties. The terminals use satellite-assisted navigation systems, mobile wireless communication functions and a module for the application function. The system uses virtual acquisition areas which can be varied dynami- cally for being adapted to new traffic situations. The traffic information is assigned to a digital road map in a data base comprised in the base station system. A difficulty of this prior art is the necessity of the frequent transmission of position information, leading to heavy mobile telephony traffic. A similar prior art is know e.g. from DE-A-10217880. Also US-A-2003/0014180 describes a system for optimising the traffic flow, based on information received via wireless telephone systems. In this prior art, too, the position information has to be transmitted to the base station rather frequently. Navigation systems exploiting the collected traffic information are known e.g. from EP-A- 1310930 or from DE-A-19930796.

Position determining systems allowing a mobile station to determine its own position are known e.g. from EP-A-0767594, from EP-A-0930513 or from DE-C- 19836778.

Besides the desire to reduce the telephone traffic between each participating mobile station and the base station to a minimum, also a subject of desired improvement is that the system can easily be adapted to very different traffic conditions, such as crowded city traffic at the one hand and motorway traffic on the other hand. While for the city traffic, traffic information is required in a geographically very dense manner, on a motorway or a cross-country road, a rather coarse grating is allowable. It is an object of the invention to reduce the telephone traffic between the mobile and the base stations for collecting the traffic data, at the same time allowing for a good adaption of the system to the geographical conditions of the respective region.

According to the invention, the coordinate data identifying pre-selected control areas of the traffic network are stored in the data base; the coordinate data identifying one of the control areas, i.e. the one wherein an observed one of the mobile stations is positioned, is transmitted, via mobile telephony, to the respective mobile station where they are temporarily stored; the single mobile station which, in time intervals, determines its position coordinates detects the occurrence of coming to and passing the border of the respective control area toward an adjacent control area, whereupon data identifying this adjacent control area are transmitted via mobile telephony to the surveying server which presents the identification of the control area to the data base where it is memorized along with a time index for further evaluation, and transmits, to the respective mobile station, data updating the coordinate data of that adjacent control area, temporarily stored, in the mobile station to then define a new control area for the same observed mobile station. By this method, a data exchange between the mobile and the base station takes place only when the mobile station leaves the control area, then being supplied with the coordinate data defining the subsequent control area. In the base equipment, the information about changing from one to another control area is sufficient for keeping a populated data store used for the required statistics and computations, and is sufficiently volatile to adapt the re-defined control areas to the geographic conditions of the observed region. Thus, in inner-city regions, the control areas will be rather small, and outside of the cities, they can be rather large.

The control areas can be defined in different ways, preferred ways being to define rings of control points surrounding the control area on the map, the minimum being two control points along a road segment, or to define the control area by one point, e.g. a centre point and a radius, or by having a grid of lines on the map.

Preferably, when the mobile station transmits the data to the base station, it sends them along with an identification code identifying the mobile station so that the progress of the single mobile station, and thus its speed, can be detected. If it is desired to keep the mobile station anonymous, a solution is preferred where the identification code is attributed and transmitted, via mobile telephony, to the mobile station from the surveying server contained in the base equipment, or is generated by the mobile station randomly, and is repeatedly changed e.g. in intervals of some tens of minutes. The time should not be too short in order to get accurate data for longer stretches.

If using the solution with a set of control points, for high-density regions like city centres, it is preferred that at least some sets of control points comprise two rings of control points, i.e. an inner ring surrounding the position of the mobile station in a closer distance and an outer ring surrounding the position of the mobile station in a - for each control point - greater distance. In such dense regions were the control areas are rather small, and assuming light traffic and a relatively high speed, it could otherwise happen that the vehicle passes the inner ring without the system realising it, e.g. since within the short time available, there is no new localisation operation.

In order to further reduce the telephone traffic between the mobile and the base stations, only such mobile stations are to be included into the process which indeed participate in the traffic to be observed. Thus, switching the respective operation of the mobile station on or off can be done manually or also can be done automatically by installing a functional connection between the vehicle and the mobile station, e.g. in that the mobile station determines whether its velocity of movement is above or below a predetermined threshold, and starts the data exchange relating to the real-time information on the road traffic situation with the base stations only after the velocity has reached the threshold for the first time, or in that the mobile station determines whether the engine of the vehicle is running, and carries out the data exchange relating to the realtime information on the road traffic situation with the base stations in such cases only where the engine is running. Further, from time to time, the surveying server checks whether it has enough or not enough data in the data base about a particular region, and instructs the mobile stations in this particular region to carry out the data exchange relating to the real-time information on the road traffic situation with the base stations in cases only where it does not have enough data about this region.

The further evaluation of the data received and stored by the service centre for road traffic surveillance comprises all the different applications known in the prior art, including navigation, inquiries by telephone or Internet, transport time forecast service etc. A useful scheme can be that the delivery of the traffic data by the mobile stations in the vehicles is free of charge, but that the different client applications exploiting the evaluation of the data are charged to the customers.

The telephony installation to be used for the method comprises mobile stations and a stationary installation which comprises stationary base stations, base station controllers and a switching network as usual, wherein, with selected ones of the base station controllers, the service centre for road traffic surveillance including a date base is coupled directly ΛΛtithout the switching network connected inbetween. Preferably, the mobile stations involved in carrying out the method comprise, besides the regular phone functionality and communication module, a geographic positioning module and a geographic coordinate data processing module receiving coordinate data from the geographic position module and from the communication module and are adapted to store the coordinate data identifying a pre-selected control area and to compare them with data received from the geographic positioning module, and in case of a positive comparison to supply the communication module with data showing the comparison result and then to wait to receive from the communication module updated coordinate data identifying the preselected control area, thereupon thereby overwriting the control area coordinate data stored before. According to a particular embodiment, the mobile station becomes an active element, monitoring its position and communicating with the surveying server according to the claimed method.

Further details, advantages and developments of the invention are defined in the subclaims and can be seen from the enclosed drawings illustrating preferred embodiments. In the drawings:

Fig. 1 shows a diagram illustrating a possible installation for carrying out the invention; Fig. 2 shows a diagrammatic and simplified map comprising an urban area and a motorway wherein the invention can be carried out; Fig. 3 shows the map of Fig. 2, illustrating a plurality of control areas each defined by several control points; Fig. 4 shows an enlarged sub-region of the map shown in Fig. 3, illustrating the movement of a mobile station through several control areas;

Fig. 5 shows another sub-region of the map of Fig. 3, presenting control areas which comprise double rings of control points; Fig. 6 shows the map of Fig. 2 using, instead of the control points of Fig. 3, a control grid; Fig. 7 shows the map of Fig. 2 wherein the control areas are circular areas defined by their centres; Fig. 8 shows a mobile station as used in Fig. 1, and its functional units; Fig. 9 illustrates the messages exchanged between the single mobile station and a service centre for road traffic surveillance; Fig.s 10 to 13 show flow-charts for different possibilities of the working of the method within the mobile station and the service centre for road traffic surveillance.

For obtaining information about the overall traffic situation within a region, a certain amount of vehicles participating in the traffic, e.g. 5 °/o thereof, carry mobile stations on board which report their position and progress, via mobile telephony and via radio base stations RBS, a base station controller BSC and a PDSN to a service centre for road traffic surveillance SCRTS to which a data memory DM and an auxiliary data base ADB are associated. The installation further comprises a usual main switch controller MSC coupled to a home location register HLR and a mobile position centre MPC which is connected to a position-determining entity PDE and to the service centre SCRTS. The modules RBS, BSC, MSC, HLR, MPC, and PDE are modules which usually are a part of the ground installation of systems like GSM and are well known to the person sldlled in the art so that a detailed description is not necessary. The SCRTS evaluates the data at first to find out about the traffic density and then to determine the speed of the vehicles which transmit their position and identity in intervals. There are several systems for identifying the position of a mobile station with relation to the radio base stations, e.g. by a triangle calculation, or by a satellite-supported system such as GPS. The SCRTS, of the data evaluated, obtains data processed which are useful for different services that are known per se, such as statistics, a telephone information centre on traffic conditions, navigation of subscribers or travel time calculation. These different services are symbolized as client applications 1, 2, ... X working via a "TPC/IP cloud".

According to the invention, a digitized map is contained in the auxiliary database ADB coupled to the SCRTS. Reference is made to Fig. 3 which illustrates one of the possibilities for the digitized map. The map contains a number of control points, the coordinate data of which are stored. These control points are generally designated 11 and, in Fig. 3, particular control points 11 are desig- nated by letters "a" to "g". The control points serve to define control areas 12, some control areas being one-dimensional and being defined by two control points 11 only, while other control areas are defined by e.g. six control points 11. The control points 11 surround a control area 12 so that motor cars which are restricted to the driveable routes can not escape from a control area 12 without passing a control point 11. One-dimensional control areas are provided for e.g. at longer distances along roads going over the country without crossroads, thus simply constituting road sections which are sequentially engaged by a vehicle running along the road. Other control areas 12, particularly within the urban region, are defined e.g. by three, four or even six control points which are established around street intersections into which the vehicle enters via one of the control points and which the vehicle exits via, usually, another one of the control points. An intersection in this meaning can also be a roundabout. A vehicle which passes a control point then is located in the next control area.

Not every section needs to be a control area. In regions where the traffic usually is moderate, it can be sufficient to combine some intersections belonging to a street grid of less important streets to constitute one single control area, as can be seen at 12a in Fig. 3.

At the beginning of an observation, the mobile station determines its position which is given by its coordinates, which can be e.g. Cartesian coordinates or polar coordinates and preferably real geographical coordinates used by GPS in conjunction with GSM system. It transmits its position to the SCRTS which replies by sending the coordinate data of the control points 11 defining the control area 12 in which the mobile station is situated. The next data exchange takes place when the mobile station, which, in intervals, determines its pdsition, detects, by comparison, that it is at one or has passed one of the control points the data of which are stored in the mobile station memory. The mobile station sends a message to the SCRTS reporting the coordinate data of the control point reached or overrun, whereupon the SCRTS realises the control area 12 the mobile station is now in, and transmits, to the mobile station, the coordinate data of the control points 11 defining this present control area 12. The coordinate data of the control points of the former control area are cancelled in the MS memory and the data of the present area are stored. Again, there is no further data exchange until the car carrying the mobile station passes the next control point.

An example is described with reference to Fig. 3, concerning a mobile station on board of a vehicle coming from the motorway and going to town. Its way is illustrated by little triangles, the control areas are illustrated by different hatching. It passes control point "a", and thereby comes into control area 12b, reporting having passed "a" and receiving the coordinate data of control points a, b, and g from SCRTS. The vehicle leaves the area 12b by passing control point b, thereby entering control area 12c. It receives the coordinate data of b, c, and d from SCRTS, which data overwrite the former data of a, b, and g. The vehicle leaves area 12c via point d and comes into control area 12d, with control points d, e, g and f. It leaves this area via control point f, entering control area 12e with control points f, h, i, and j, which it leaves via control point i.

Fig. 4 shows a detail from the map of Fig. 3, the letter-numbering of the control points 11 in Fig. 4 again starting with "a", and the following route of a vehicle is assumed: one-dimensional control area 12f; control point d; control area 12g with control points c, d, e, f, g, and h; control point g; control area 12h with control points f, g, n, o, \ j; control point n; control area 12i with control points n, q, r, o; control point r; longitudinal control area 12j.

Another section of the map of Fig. 3 is shown in Fig. 5. Here, some adjacent control areas 12 overlap and each of these control areas consists of two rings of control points. Five control areas 12k, 121, 12m, 12n and 12o are shown, again illustrated by different types of hatching and each having two rings of control points which rings are made clear by a different density of the hatching, wherein, in the depicted example, some of the control points of the outer ring of one control area also belong to the inner ring of the adjacent control area. Such double rings are of interest in cases where the control areas are rather small because of a usually dense traffic, while at other times with low traffic a vehicle might go on quite fast and leave small areas almost too early, so that the respective control point 11 rather is overrun, and when the next positioning information arrives, the vehicle already passes the outer ring of control points.

As far as described at present, the system provides for traffic density informa- tion, reporting a higher or lower number of vehicles within a control area.

According to a higher level of information, the mobile stations also transmit an identity signal to the SCRTS and the SCRTS stores the data of the control points passed, together with a time stamp indicating the time of receipt. This allows the system to trace the individual vehicles and thereby calculate the speed of each vehicle and consequently the average speed of the vehicles in a particular area or region. The vehicle identity signals are not permanent identity signals like the telephone number of the mobile station but are numbers which change in intervals so that the single mobile station stays anonymous.

The system using the control points 11 can be adapted very finely to a specific map and to the experience where traffic occurs. A different approach is shown in Fig. 6 where a grid consisting of horizontal lines 16 and vertical lines 17 is superimposed on the map. In Fig. 6, the lines 16 and the lines 17 have equal distances in the urban region and also heave equal, but wider distances in the rural region. One way of cutting off every' second line 16 at a particular vertical line 17' could be not to take the coordinate data of e.g. the impair lines 16 beyond the horizontal data of line 17' into account any longer. An even more specific dimensioning of the grid cells is, of course, possible. In the depicted example, the mobile station reports to the SCRTS each time it passes one of the lines 16 or 17, thereby automatically entering the next control area. The mobile station stores the coordinate data of one line 16 and one line 17, which lines are updated at each passing of one of the lines. If the vehicle crosses a corner of one of these cells, the mobile station will, after some time, realize between which lines 16 and 17 and thus in which control area 12 it is located.

Fig. 7 shows an arrangement where the control areas 12 are identified by a central point and a radius, or, if the radius is constant all over the map, by the coordinate data of the central point only. The control areas are circular and overlap to a small extent, which is not harmful. When the next positioning of the mobile station shows that the distance to the centre point stored has exceeded the radius, several solutions are possible for finding out which next centre point has to be transmitted to the mobile station. The SCRTS can calculate which centre point is the next centre point from the vehicle position the coordinate data of which had been transmitted; or the position coordinates of the mobile station are used to determine a peripheral sector of the circular control are, and this arc-shaped sector identifies the adjacent control area and the centre point thereof; or, if the positioning system also recognizes the movement orientation of the vehicle, this information can be taken into account for identifying the control area entered.

Fig. 8 illustrates the mobile station MS and its elementary functions within the present method. It comprises a communication module 20 adapted for the radio communication with the base stations RBS of the stationary installation, and a regular phone module 21. Module 20 is connected to an application module 22 which includes all installations and programmes needed to process primary traffic information, which it receives from a geographic positioning module 23.

From this module 23, module 22 receives the coordinate data of the instantaneous position of the mobile station, which data are to be sent, via module 20, to the next radio base station RBS and further on to the service centre SCRTS. The application module decides when to access the geographic positioning module 23 for obtaining the coordinate data, it compares these data with stored data relating to control points, control lines etc. according to the method used, and decides when and how to communicate with SCRTS. Depending on the schedule used, it can also communicate furtlner data if provided for by the system. In the example depicted, also a trigger module 24 is connected to module 22, intended to switch the programmes in module 22 for starting the method of the invention. Module 24 can consist of a manual operation module, a speed detector receiving its input from the positioning module 23, or a trigger input connected to the vehicle engine which siipplies a trigger when starting the engine, or connected to the speedometer of the vehicle to send a trigger upon reaching a predetermined speed of e.g. 30 km/h. The trigger starts the activity of module 22. Optionally, also a trigger can be provided for interrupting the method by switching off module 22.

Fig. 9 shows an example for the message exchange between the mobile station and the base station when performing the method.

Fig. 10 presents a flow-chart illustrating an example of the operations performed by the mobile stations MS. In a step 31, the mobile phone waits for a trigger indicating e.g. the start of movement of the vehicle. In step 32, it internally detects that one of the triggers for detecting movement is satisfied. In steps 33, it starts the communication with SCRTS to check if it should take part in the traffic observation. If SCRTS, in step 34, answers "no", MS waits for another trigger in step 35, checks the trigger in step 36, and, if the result is positive, again inquires with SCRTS whether it should now take part in the traffic observation.

Once in step 34 SCRTS answers "yes", MS receives, at first, an anonymous identification code to be used for the further position reports, and also receives additional communication and connection information in step 37. Then, in step 38, MS receives, if using the method of Fig. 3, the coordinate data of the control points 11 of the control area 12 MS is situated in, or, if using the method of Fig.s

6 or 7, the coordinate data of lines 16, 17 or of the centre point 18, respectively. In step 39, MS monitors its own position, compares it to the data received in step 38 and communicates the data of a control point 11, a line 16 or 17 or of a direction in which it leaves a control area 12 when it reaches a relevant position, and communicates the result to SCRTS in step 39. Then, in step 40, it waits for another information from SCRTS whether, for the new control area entered by MS, traffic data are required or not. If "no", it returns to step 35, if "yes", it returns to step 38.

Fig. 11 shows the operations performed by MS in more detail. The detailed steps are described in the drawing and in order not to> overburden the description, are not once more listed here. Disclosure thereof as far as shown in the drawing is however claimed to have been provided for.

Fig. 12 illustrates the server SCRTS schematically.. The surfer SCRTS comprises a communication module 44 connected to the base station controller BSC and further, via the radio base stations RBS, to the mobile stations MS. At the other side, module 44 is connected to a data acquisition module 45 which is connected to an internal memory 46. To this, a data processing module 47 has access which further presents the data to a main data base 48 which is con- nected to a communication module 49 further connected to the applications.

The main data base 48 has to be populated with data relating to the traffic situation and the applications. Populating the data base SCRTS will be carried out as follows, reference being made to Fig.13:

The initial status or the status after a restart or a reload of the surfer is shown as step 51. In this step, the main data base 48 and the additional data base, i.e. the memory 46, do not yet contain any data, i.e. the are not populated. In step 52, SCRTS sends messages to the mobile stations MS stating that traffic informa- tion is required. In step 53, communication with the mobile stations takes place and the system selects mobile stations that will be monitored in all regions of interest. In next step 54, SCRTS receives traffic information from the monitored mobile stations, and in next step 55, memory 46 is populated with the information received from the mobile stations. While this memory 56 is populated, it repeatedly returns to steps 53 and 54- for receiving more information from the selected mobile stations. Then, in step 56, the data processing module 47 is triggered to start populating the main data base 48. If no trigger is present, module 47 waits for such trigger. If it is present, step 57 starts, reading in memory 46, processing the data read and writing in the main data base 47 data which reflect the real time traffic situation over the entire monitored area.

Claims

1. Method of obtaining in real time information on the road traffic situation in a road network, the method comprising collecting repeatedly position coordinate data from selected mobile stations on board of vehicles participating in the traffic to be observed and being included in a position detection system, which coordinate data are determined by the position detection systems and are transmitted via mobile telephony to a traffic data base operatively connected to a surveying server and to base stations of the mobile telephone system, characterized in that the coordinate data identifying pre-selected control areas of the traffic network are stored in the data base; that the coordinate data identifying one of the control areas, i.e. the one wherein an observed one of the mobile stations is positioned, is transmitted via mobile telephony to the respective mobile station where they are temporarily stored; that the single mobile station which in time intervals determines its position coordinates detects the occurrence of coming to and passing the border of the respective control area toward an adjacent control area, whereupon data identifying this adjacent control area are transmitted via mobile telephony to the surveying server which presents the identification of the control area to the data base where it is memorized along with a time index for further evaluation, and transmits to the respective mobile station data updating in the mobile station the temporarily stored coordinate data of that adjacent control area to then constitute a new control area for the same observed mobile station.

2. Method according to claim 1, characterized in that the coordinate data of the control area, to be used, are the coordinate data of pre-selected control points of the traffic network which control points are positioned at the border of the control area and the coordinate data thereof are stored in the data base; that the coordinate data of this set of control points in the vicinity of the position of the single mobile station are transmitted via mobile telephony to the respective mobile stations where they are temporarily stored; that the mobile station detects the occurrence of coming to o r passing one of the temporarily stored control points, whereupon identification data of this control point are transmitted via mobile telephony to the surveying server which presents the identification of the control point to the data base where it is memorized along with a time index for further evaluation, and transmits to the respective mobile station data updating in the mobile station the temporarily stored coordinate data of the control points to then relate to a new set of control points.

3. Method according to claim 1, characterized in that the coordinate data identifying the pre-selected control areas are the coordinate data of a characteristic control point, preferably the centre point of the control area, together with an algorithm, preferably a radius, for defining the control area in dependency of the control point; and that the coordinate data of the control point of the control area comprising the position of the single mobile station are transmitted via mobile telephony to the respective mobile stations where they are temporarily stored.

4. Method according to claim 1, characterized in that the coordinate data identifying the pre-selected control areas are the coordinate data of pre-defined lines oriented in at least two different inclinations, thus altogether constituting a grid comprising grid windows between the lines, the coordinate data to be transmitted to the respective mobile stations being data identifying the lines defining the grid window comprising the position of the single mobile station.

5. Method according to any of claims 1 to 4, characterized in that the mobile station transmits the identification of the control area, of the control point or of the lines, respectively, to the surveying server along with an identification code identifying the mobile station.

6. Method according to claim 5, characterized in that the identification code is a temporary identification code identifying the respective mobile station for calculating its movement by the surveying server only.

7. Method according to claim 6, characterized in that the temporary identification code is attributed by and transmitted via mobile telephony to the mobile station from the surveying server, and is repeatedly changed.

8. Method according to claim 6, characterized in that the temporary identification code is generated by the mobile station randomly and is repeatedly changed.

9. Method according to claim 2 or any of claims 5 to 8 if referred to claim 2, characterized in that the data updating in the mobile station the coordinate data to then relate to a new set of control points are the coordinate data of the control points which in the road network adjacently surround the control point identified in this operation phase.

10. Method according to claim 2 or any of claims 5 to 9 if referred to claim 2, characterized in that at least some sets of control points comprise two rings of control points, i.e. an inner ring surrounding the position of the mobile station in a closer distance and an outer ring surrounding the position of the mobile station in a - for each control point - more distant distance.

11. Method according to any of claims 1 to 10, characterized in that the position detecting system is a mobile telephone position detecting system.

12. Method according to any of claims 1 to 11, characterized in that the mobile station determines whether its velocity of movement is above or below a predetermined threshold, and starts the data exchange relating to the real time information on the road traffic situation with the base stations only after the velocity has reached the threshold for the first time.

13. Method according to any of claims 1 to 11, characterized in that the mobile station determines whether the engine of the vehicle is running, and carries out the data exchange relating to the real time information on the road traffic situation with the base stations in such cases only where the engine is running.

14. Method according to any of claims 1 to 13, characterized in that the surveying server checks whether it has enough or not enough data in the data base about a particular region, and instructs the mobile stations in this particular region to carry out the data exchange relating to the real time information on the road traffic situation with the base stations in cases only where it does not have enough data about this region.

15. Method according to any of claims 1 to 14, characterized in that the further evaluation comprises traffic statistics.

16. Method according to any of claims 1 to 15, characterized in that the further evaluation comprises repeatedly updating a centralized information base which is remotely interrogatable.

17. Method according to any of claims 1 to 16, characterized in that the further evaluation comprises a centralized dynamic routing service, to be ordered via mobile telephony by transmitting to the surveying server identification data of a starting point and at least one destination point in the road network, and sending to the respective mobile station indications of routes optimized according to selected criteria.

18. Method according to claim 17, characterized in that the data of the optimized route, received by the mobile station, are supplied to a navigation system installed on board of a respective vehicle for partly overwriting the map information used in said system. 5

19. Method according to any of claim 1 to 18, characterized in that the further evaluation comprises a transport time forecast service.

20. Mobile telephony installation adapted to carry out the method according0 to any of claims 1 to 19, comprising mobile stations (MS), stationary base stations (RBS), base station controllers (BSC) and a switching network (MSC), characterized in that with selected ones of the base station controllers (BSC), a server (SCRTS) which is a service centre for road traffic surveil-5 lance including a date base is coupled directly without the switching network (MSC) connected inbetween.

21. Mobile telephony installation according to claim 20, characterized in that the mobile stations (MS) involved in carrying out the o method comprise, besides the regular phone functionality and communication module, a geographic positioning module and a geographic coordinate data processing module receiving coordinate data from the geographic position module and from the communication module and are adapted to store the coordinate data identifying a pre-selected control area and to compare them with data received from the geographic positioning module, and in case of a positive comparison to supply the communication module with data showing the comparison result and then to wait to receive from the communication module updated coordinate data identifying the preselected control area, thereupon thereby overwriting the control area coordinate data stored before.

22. Mobile telephony installation according to claim 20 or 21, characterized in that the mobile stations (MS) is an active element.