Patent Publication Number: US-2022240064-A1

Title: Vehicle-sharing system and method for accessing a vehicle from such a system

Description:
RELATED APPLICATIONS 
     This application is a § 371 application of PCT/EP2020/067012 filed Jun. 18, 2020, which claims priority from French Patent Application No. 19 06591 filed Jun. 19, 2019, each of which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention belongs to the field of systems for sharing vehicles between various users. In particular, the invention relates to a method and a system for accessing a vehicle shared by a user subscribing to a vehicle-sharing service. 
     BACKGROUND OF THE INVENTION 
     A vehicle-sharing service, also known by the term carshare service or self-service vehicle service, is a system wherein vehicles are made available to a group of users who have taken out a subscription to said sharing service. 
     Rather than having a personal vehicle that is sometimes used only on rare occasions, a user of a vehicle-sharing service can access a vehicle that they finance, via their subscription, only for the duration they need. For the rest of the time, the vehicle can be used by other users subscribing to the sharing service. The use of a shared vehicle may for example be invoiced to the user according to the type of vehicle, the duration of the reservation, the distance travelled, etc. 
     So that only one user who has taken out a subscription to a vehicle-sharing service can access a shared vehicle of said service, it is necessary to implement methods for limiting access to a shared vehicle. 
     Among the existing vehicle-sharing systems, it is known that a user wishing to access a vehicle in a fleet of shared vehicles uses an application on their mobile telephone to identify a vehicle available in proximity to the geographical position where the user is located and to release access to said vehicle. 
       FIG. 1  schematically shows such a vehicle-sharing system  10  of the prior art. As illustrated on  FIG. 1 , the vehicle-sharing system  10  includes in particular a vehicle  13 , a server  11  and a mobile telephone  14  of a user wishing to access the vehicle  13 . 
     The server  11  has access to a database  12  wherein a list of vehicles belonging to the fleet of shared vehicles is stored. The geographical position of each vehicle is for example kept up to date in the database. The database  12  also includes subscription information for each user registered for the vehicle-sharing service. 
     A first communication link  15  between the mobile telephone  14  and the server  11  can be established, for example according to a first wireless communication system  150 , for example a cellular system such as GSM, 3G or LTE. Information can then be exchanged between a mobile application installed on the mobile telephone  14  and the server  11 . In particular, the application may enable the user to see, on a map displayed on the screen of the telephone, the location of the shared vehicles located in a geographical area close to the user. The user can also select a particular shared vehicle  13  and reserve it with the server  11 . For this purpose, an identifier of the vehicle and information relating to the subscription of the user (for example an identifier of the user, a client number, etc.) are transmitted by the mobile telephone  14  to the server  11 . The server  11  can then verify the subscription information of the user stored in the database from the subscription information received from the mobile telephone  14 . If the verification succeeds, the server  11  creates a temporal authentication key enabling the user to release access to the vehicle  13 . This temporal authentication key is sent on the one hand to the mobile telephone  14  over the first communication link  15  between the server  11  and the mobile telephone  14 , and on the other hand to the vehicle  13  over a second communication link  16  between the vehicle  13  and the server  11  according to a second wireless communication system  160 . The second wireless communication system  160  may be identical to or different from the first wireless communication system  150 . A third communication link  17  between the mobile telephone  14  and the vehicle  13  is then established according to a third wireless communication system  170 . On this communication link  17 , the mobile telephone  14  can send to the vehicle  11  the temporal authentication key received from the server  11 . If the authentication key received from the terminal  14  is identical to the authentication key received from the server  11 , the vehicle  13  releases its access (for example an anti-theft device on the steering column of the vehicle  13  is unlocked). The third wireless communication  170  may be identical to or different from the first wireless communication system  150  and/or the second wireless communication system  150 . 
     Such a solution does however have a cost for the user when the communications exchanged between the mobile telephone  14  and the server  11  or between the mobile telephone  14  and the vehicle  13  are paid. In particular, when the first wireless communication system  150  and/or the third wireless communication system  170  is a cellular system (GSM, 3G or LTE), and when the user is roaming outside the country for which they have taken out their mobile telephone contract, the cost of the communications on the communication links  15  and  17  may be particularly high. Furthermore, if the user is located in a system in which their telephone contract does not enable them to communicate, the user finds it impossible to use the shared-vehicle service. 
     OBJECT AND SUMMARY OF THE INVENTION 
     The objective of the present invention is to remedy all or some of the drawbacks of the prior art, in particular those described above, by proposing a solution wherein a user does not need to establish a direct communication with the server of a vehicle-sharing service to reserve and access a vehicle. 
     For this purpose, and according to a first aspect, the present invention proposes a vehicle-sharing system. The vehicle-sharing system includes at least one vehicle, at least one terminal of a user wishing to access said vehicle, and a server having access to a database including information on subscription of said user to a vehicle-sharing service. The vehicle and the terminal each include a first communication module making it possible to establish a first communication link between the terminal and the vehicle according to a first wireless communication system. The vehicle also includes a second communication module making it possible to establish a second communication link between the vehicle and the server according to a second wireless communication system. The terminal is configured to identify the vehicle from a local database of the terminal. The local database includes in particular a list of vehicles likely to be used by the user and, for each vehicle in the list, information making it possible to establish a communication between said vehicle and the terminal on the first communication link. The terminal is configured to establish, on the first communication link, a pairing connection with the vehicle and to send to the vehicle a reference to the subscription of the user to the vehicle-sharing service. The vehicle is configured to transmit said reference to the server on the second communication link. The server is configured to verify the subscription information of the user present in the database of the server from the transmitted reference by the vehicle and, if the verification succeeds, to send to the vehicle, on the second communication link, an authorization for access to the vehicle in order to remotely allow the user to access the vehicle. 
     The information making it possible to establish a communication between the vehicle and the terminal is for example an identifier, an MAC (“medium access control”) address, an authentication key, etc. This information may be limited to a single particular parameter or consist of a combination of several different parameters. Such information can in particular make it possible to establish a secure reliable communication link between the terminal and the vehicle. 
     The reference to the subscription of the user is a data item that makes it possible to identify the subscription of the user from all the subscriptions stored in the database of the server. The reference to the subscription of the user enables the vehicle to interrogate the server on the status of the subscription. The reference to the subscription may be an identifier of the user (for example an email address), a client number, or a subscription number, etc. 
     With such provisions, and unlike the solutions of the prior art, there is no longer any need to establish a direct communication link, potentially expensive for the user, between the terminal and the server. 
     This is because, in the solution proposed, the vehicle fulfils the role of intermediary between the terminal and the server. A free ad hoc communication link that does not use an infrastructure can for example be used between the terminal and the vehicle. The cost relating to the communication link between the vehicle and the server for its part is not borne by the user. This cost can in fact be borne by the manager of the vehicle-sharing service. 
     In particular embodiments, the invention may furthermore include one or more of the following features, taken in isolation or in accordance with all the technically possible combinations. 
     In particular embodiments, the first wireless communication system and the second wireless communication system are distinct. 
     In particular embodiments, the second wireless communication system is a low-power wide-area network. 
     This is because, even if in the invention nothing obliges the first wireless communication system and the second wireless communication system to be distinct, it is however advantageous for the first communication system to offer a free short-range ad hoc wireless communication link, and for the second communication system to offer a long-range wireless communication link with low electrical consumption. 
     According to a second aspect, the present invention relates to a method for access to a vehicle by a user of a vehicle-sharing system. The vehicle-sharing system includes a server having access to a database including information on subscription of said user to a vehicle-sharing service. The vehicle is adapted to communicate with a user terminal on a first communication link according to a first wireless communication system. The vehicle is also adapted to communicate with the server on a second communication link according to a second wireless communication system. The method includes the following steps:
         an identification of the vehicle by the terminal from a local database of the terminal, said local database including a list of vehicles likely to be used by the user and, for each vehicle in the list, information making it possible to establish a communication between said vehicle and the terminal on the first communication link,   a pairing between the terminal and the vehicle on the first communication link,   a sending, by the terminal, to the vehicle, on the first communication link, of a reference to the subscription of the user to the vehicle-sharing service,   a transmission of said reference by the vehicle to the server on the second communication link,   a verification, by the server, of the subscription information of the user present in the database of the server from the transmitted reference,   if the verification succeeds, a sending, by the server, to the vehicle, on the second communication link, of an authorization for access to the vehicle in order to remotely allow the user to access the vehicle.       

     In particular embodiments, the invention may furthermore include one or more of the following features, taken in isolation or in accordance with all the technically possible combinations. 
     In particular embodiments, the method further includes a prior step of loading the local database onto the terminal, said local database being associated with a geographical area in which the vehicles in the list stored in said local database are located. 
     According to a third aspect, the present invention relates to a server of a vehicle-sharing system. The server has access to a database including information on subscription to a vehicle-sharing service for at least one user wishing to access a shared vehicle. The server includes a communication module for communicating with said vehicle on a communication link between the vehicle and the server. The server is configured to receive, on said communication link, a reference to the subscription of the user transmitted by the vehicle, to verify the subscription information of the user present in the database of the server from said reference and, if the verification succeeds, to send to the vehicle, on said communication link, an authorization for access to the vehicle in order to remotely allow the user to access the vehicle. 
     According to a fourth aspect, the present invention relates to a computer program product for a server of a vehicle sharing system. The server has access to a database including information on subscription to a vehicle-sharing service for at least one user wishing to access a shared vehicle. The server is adapted to communicate with said vehicle on a communication link between the vehicle and the server. Said computer program product includes a set of program code instructions which, when they are executed by one or more processors of the server, configure the processor or processors for implementing the following steps:
         receiving, on said communication link, a reference to the subscription of the user transmitted by the vehicle,   verifying the subscription information of the user present in the database of the server from said reference,   if the verification succeeds, sending to the vehicle, on said communication link, an authorization for access to the vehicle in order to remotely allow the user to access the vehicle.       

     According to a fifth aspect, the present invention relates to a vehicle of a vehicle sharing system. The system includes a server having access to a database including information on subscription to a vehicle-sharing service for at least one user wishing to access a shared vehicle. The vehicle includes a first communication module making it possible to establish a first communication between the vehicle and a terminal of the user according to a first wireless communication system. The vehicle also includes a second communication module making it possible to establish a second communication link between the vehicle and the server according to a second wireless communication system. Furthermore, the vehicle is configured to:
         receive, on the first communication link, a reference to the subscription of the user to the vehicle-sharing service sent by the terminal,   transmit said reference to the server on the second communication link,   receive, on the second communication link, an authorization for access to the vehicle sent by the server if the subscription information of the user present in the database of the server is correctly verified from said reference.       

     According to a sixth aspect, the present invention relates to a computer program product for a control unit of a vehicle of a vehicle-sharing system. Said system including a server having access to a database including information on subscription to a vehicle-sharing service for at least one user wishing to access a shared vehicle. Said vehicle is adapted to communicate with a terminal of the user on a first communication link according to a first wireless communication system. The vehicle is also adapted to communicate with the server on a second communication link according to a second wireless communication system. Said computer program product includes a set of program code instructions which, when they are executed by one or more processors of the control unit, configure the processor or processors for implementing the following steps:
         receiving, on the first communication link, a reference to the subscription of the user to the vehicle-sharing service sent by the terminal,   transmitting said reference to the server on the second communication link,   receiving, on the second communication link, an authorization for access to the vehicle sent by the server if the subscription information of the user present in the database of the server is correctly verified from said reference.       

     According to a seventh aspect, the present invention relates to a terminal of a user of a vehicle-sharing system. Said terminal includes a wireless communication module making it possible to establish a communication link between the terminal and a vehicle of the vehicle-sharing system. The terminal is furthermore configured to:
         identify the vehicle from a local database of the terminal, said local database including a list of vehicles likely to be used by the user and, for each vehicle in the list, information making it possible to establish a communication between said vehicle and the terminal on the communication link,   establish, on the communication link, a pairing connection with the vehicle,   send to the vehicle a reference to the subscription of the user to the vehicle-sharing service.       

     A remote access to the vehicle is enabled by a server of the vehicle-sharing system if the subscription information of the user present in the database of the server is correctly verified by the server from said reference. 
     According to an eighth aspect, the present invention relates to a computer program product for a control unit of a terminal of a user of a vehicle sharing system. The terminal is adapted to communicate with a vehicle of the vehicle-sharing system on a wireless communication link. The computer program product includes a set of program code instructions which, when they are executed by one or more processors of the control unit, configure the processor or processors for implementing the following steps:
         identifying the vehicle from a local database of the terminal, said local database including a list of vehicles likely to be used by the user and, for each vehicle in the list, information making it possible to establish a communication between said vehicle and the terminal on the communication link,   establishing, on the communication link, a pairing connection with the vehicle,   sending to the vehicle a reference to the subscription of the user to the vehicle-sharing service.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be understood better from a reading of the following description, given by way of non-limitative example and made with reference to  FIGS. 1 to 6 , which show: 
         FIG. 1  is a schematic representation of a vehicle-sharing system according to the prior art, 
         FIG. 2  is a schematic representation of a vehicle-sharing system according to the invention, 
         FIG. 3  is a schematic representation of a terminal of a user of the vehicle-sharing system according to the invention, 
         FIG. 4  is a schematic representation of a vehicle of the vehicle-sharing system according to the invention, 
         FIG. 5  is a schematic representation of the main steps of a method for access to a vehicle of a vehicle-sharing system according to the invention, 
         FIG. 6  is a message-sequence diagram representing the concatenation of the steps of a method for access to a vehicle of a vehicle-sharing system according to the invention. 
     
    
    
     In these figures, references that are identical from one figure to another designate identical or similar elements. For reasons of clarity, the elements shown are not necessarily to the same scale, unless mentioned to the contrary. 
     DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION 
     As indicated previously, the present invention aims in particular to propose a vehicle-sharing system and a method for access to a shared vehicle for which a user does not need to establish a direct communication with a server of the vehicle-sharing service at the time when the user wishes to reserve and access a vehicle. 
       FIG. 2  schematically shows an example of a vehicle-sharing system  20  according to the invention. As illustrated in  FIG. 2 , the vehicle-sharing system  20  includes in particular at least one vehicle  40 , a server  30  and at least one terminal  50  of a user wishing to access the vehicle  40 . 
     In the remainder of the description, and by way of in no way limitative example, it is considered that the terminal  50  is a mobile telephone. It should however be noted that the terminal  50  could also be a connected bracelet, a connected watch, a simple chip card, or any other electronic device including the electronic components necessary for fulfilling the functions of the terminal  50 . 
     In the example considered and illustrated in  FIG. 2 , the vehicle  40  is a motorcycle. It should however be noted that it could be a case of another type of vehicle, such as for example a car, a bicycle, an electric scooter, etc. The choice of a particular type of vehicle is merely a variant of the invention. 
     The server  30  has access to a database  31  in which subscription information is stored for each user subscribing to the vehicle-sharing service supported by the system  20 . The database may for example be directly integrated in the server  30 . According to another example, the database  31  may be a physical entity distinct from the server  30 , and the server may communicate, in a conventional manner, with the database  31  to record information in the database  31  or to obtain information stored in the database  31 . 
     In the database  31  of the server  30 , the subscription information of a user subscribing to the vehicle-sharing service includes for example an identifier of the user (such as an email address, a client number, etc.), information on characteristics of the subscription (for example a maximum authorised mileage, or a maximum authorized number of borrowings of a vehicle, etc.), payment options (for example a bank card number, or a balance of the user account following a payment that was made by the user, etc.). 
     The server  30  includes one or more processors and storage means (magnetic hard disk, electronic memory, optical disc, etc.) wherein a computer program product is stored, in the form of a set of program code instructions to be executed for implementing at least some of the steps of a method for access to the vehicle  40  of the vehicle-sharing system  20 . 
     The server  30  also includes a communication module to exchange messages with the vehicle  40 . 
     As illustrated in  FIG. 3 , the terminal  50  of a user includes a communication module  51  for establishing a first communication link  61  between the terminal  50  and the vehicle  40  according to a first wireless communication system  60 . 
     Various choices are possible for the first wireless communication system  60 , and the choice of a particular communication system is merely a variant of the invention. However, the first wireless communication system  60  can advantageously be selected to offer a free short-range ad hoc wireless communication link  61 . “Ad hoc communication link” means that no network infrastructure is necessary for establishing the communication link between the terminal  50  and the vehicle  40 . “Short range” means that the maximum distance between the terminal  50  and the vehicle  40  must be less than a few meters, or even a few tens of meters, so that messages can be exchanged between the terminal  50  and the vehicle  40  on the communication link  61 . Using a short-range communication link  61  makes it possible in particular to ensure that the user is in proximity to the vehicle  40  (for example at less than five meters from the vehicle  40 ) at the moment when the user initiates a procedure for authorization of access to said vehicle. For example, the first wireless communication system  60  corresponds to the Bluetooth (based on IEEE 802.15.1), NFC (“Near Field Communication”, an extension to ISO/IEC 14443), ZigBee (based on IEEE 802.15.4), or Wi-Fi (based on the IEEE 802.11 standards) communication standard. Advantageously, the first wireless communication system  60  is a low energy consumption system, so that the terminal  50  and the vehicle  40  can use a relatively low-capacity battery that it is not necessary to change or recharge regularly. 
     As illustrated in  FIG. 3 , the terminal  50  furthermore includes a local database  52 . The local database  52  includes in particular a list of vehicles likely to be used by the user and, for example vehicle in the list, information making it possible to establish a communication between said vehicle and the terminal  50  on the first communication link  61 . 
     The local database  52  is for example downloaded onto the terminal  50  by the user. The local database  52  may include the list of all the vehicles of the vehicle-sharing service, whatever the geographical position of the vehicles. In a variant, the local database  52  may be associated with a geographical area in which the vehicles in the list stored in said local database  52  are located. Said geographical area may for example be a town, a region of a country, a country, or even a continent. Thus a user expecting to stay in a particular geographical area can download onto their terminal the local database associated with said geographical area so that, once they have arrived in the geographical area in question, the user can have access to the vehicles of the vehicle-sharing service located in this geographical area. 
     When the user has ended their stay in this geographical area, they can then delete the associated local database in order to release memory space in their terminal  50 . 
     Optionally, the local database  52  may also include geographical positions of parking points of the vehicles in the car-sharing service. These geographical positions can assist the user in going to these parking points to borrow a vehicle. 
     The information contained in the local database  52  making it possible to establish a communication between the vehicle  40  and the terminal  50  includes for example an identifier, an MAC address, an authentication key, etc. 
     By way of example, if the information relating to a vehicle (MAC address, authentication key) can be encoded in forty bytes, a local database  52  of three megabytes (3 MB) can contain a list of forty-five thousand ( 45 , 000 ) vehicles. 
     It should be noted that the local database  52  is not downloaded onto the terminal  50  over a communication link between the server  30  and the terminal  50  at the moment when the user wishes to have access to the vehicle  40 . The local database  52  is loaded upstream, before the user is located in proximity to the vehicle  40 . The local database  52  may for example be loaded into the terminal  50  by means of a memory card inserted in the terminal  50 . According to another example, the local database  52  may be downloaded by the terminal  50  via the internet at a moment and in a place where the user may have access to the internet with the terminal  50  free of charge. 
     As illustrated in  FIG. 3 , the terminal  50  also includes a control unit  53  including one or more processors and storage means (magnetic hard disk, electronic memory, optical disc, etc.) in which a computer program product is stored, in the form of a set of program code instructions to be executed for implementing at least some of the steps of a method for access to the vehicle  40  of the vehicle-sharing system  20 . 
     The terminal  50  is in particular configured to identify the vehicle  40  from the local database  52 . For example, each vehicle  40  of the car-sharing system  20  recurrently sends over the first communication link  61  a radio signal including a message including an identifier of the vehicle. The terminal  50  can decode the message and seek whether a vehicle in the list stored in the local database  52  has as its identifier the identifier contained in the message. 
     If the user is in proximity to a plurality of vehicles of the carshare service and the terminal  50  receives a plurality of radio signals sent by various vehicles, the terminal may decide to decode the message corresponding to the radio signal for which a parameter representing the quality of the radio signal has the highest value. 
     Such a parameter representing the quality of the radio signal may for example correspond to a power level received by the terminal  50  for said radio signal (“Received Signal Strength Indicator” or RSSI) or to a signal to noise ratio (SNR) of said radio signal. 
     According to another example, the terminal  50  can identify a vehicle  40  from an identifier corresponding to a serial number or to a registration number visible on the vehicle  40 . The identifier can be indicated by the user to the terminal  50  via a graphical interface of the terminal  50 . The terminal  50  can next seek whether a vehicle in the list stored in the local database  52  has as its identifier the indicated identifier. 
     According to yet another example, the terminal  50  can propose means (for example a photographic apparatus) for scanning a bar code or a QR (“Quick Response”) code visible on the vehicle  40  and corresponding to an identifier of the vehicle  40 . The terminal  50  can next seek whether a vehicle in the list stored in the local database  52  has as its identifier the identifier corresponding to the scanned code. 
     Other methods for identifying the vehicle  40  from the local database  52  of the terminal  50  can be envisaged. The choice of a particular method is merely a variant of the invention. 
     The terminal  50  is also configured to establish, on the first communication link  61 , a pairing connection with the vehicle  40  and to send to the vehicle  40  a reference to the subscription of the user to the vehicle-sharing service. 
     The pairing connection corresponds for example to an exchange of an authentication key between the terminal  50  and the vehicle  40 . The authentication key to be used forms part of the information of the local database  52  associated with the vehicle  40  identified. This pairing connection makes it possible to establish a communication between the terminal  50  and the vehicle  40  over the first communication link  61 . 
     The reference to the subscription of the user sent by the terminal  50  corresponds for example to an identifier of the user (email address, client number) or to an identifier of the subscription (subscription number). 
     As illustrated in  FIG. 4 , the vehicle  40  includes a first communication module enabling it to exchange messages with the terminal  50  over the first communication link  61 . 
     The vehicle  40  also includes a second communication module  42  enabling it to exchange messages with the server  30  over a second communication link  71  according to a second wireless communication system  70 . 
     Various choices are possible for the second wireless communication system  70 , and the choice of a particular communication system is merely a variant of the invention. The second wireless communication system  70  may be identical to or distinct from the first wireless communication system  60 . It should moreover be noted that, if the first wireless communication system  60  and the second wireless communication system  70  are identical, the first communication module  41  and the second communication module  42  may be a single physical entity. 
     However, the second wireless communication system  70  may advantageously be selected to offer a communication link  71  having a range of several kilometers and limited requirements in terms of electrical consumption, so that the vehicle  40  can exchange messages with the remote server  30  using a battery that it is not necessary to change or recharge regularly. 
     In particular embodiments, the second wireless communication system  70  is a wireless wide-area network with low electrical consumption known by the term LPWAN (“Low Power Wide Area Network”). Such a wireless communication system is an access network with long range (greater than one kilometer, or even greater than a few tens of kilometers), with low energy consumption (for example an energy consumption during transmission or reception of a message of less than 100 mW, or even less than 50 mW, or even less than 25 mW), and the bit rates of which are generally less than 1 Mbits/s. Such wireless communication systems are particularly adapted to applications involving connected objects (“Internet of Things” or IoT in the literature). 
     In particular embodiments, the wireless communication system  10  may be an ultra-narrow band communication system. “Ultra Narrow Band” or UNB in the literature means that the instantaneous frequency spectrum of the radio signals transmitted by the terminals has a frequency width of less than two kilohertz, or even less than one kilohertz. Such a system makes it possible to significantly limit the electrical consumption of the terminals when they communicate with the access network. 
     The server  30  is connected to the second wireless communication system  70 . For example, the server  30  is directly connected to an access network of the second wireless communication system  70 . According to another example, the server  30  and the access network of the second wireless communication system  70  are both connected to the internet, and a communication can thus be established between the vehicle  40  and the server  30  through both an access network of the second wireless communication system  70  and the internet. 
     As illustrated in  FIG. 4 , the vehicle  40  furthermore includes a control unit  43  including one or more processors and storage means (magnetic hard disk, electronic memory, optical disc, etc.) wherein a computer program product is stored, in the form of a set of program code instructions to be executed for implementing at least some of the steps of a method for access to the vehicle  40  of the vehicle-sharing system  20 . 
     The vehicle  40  is in particular configured to transmit the reference to the subscription received from the terminal  50  to the server  30  over the second communication link  71 . 
     The server  30  is configured to verify the subscription information of the user present in the database  31  of the server  30  from the reference to the subscription transmitted by the vehicle  40 . 
     If the verification succeeds, the server  30  is configured to send to the vehicle  40 , over the communication link  71 , an authorization for access to the vehicle  40  in order to allow remote access of the user to the vehicle. 
     Verifying the subscription information of the user consists for example in ensuring that the payment means of the user (the balance of the account of the user, the bank card number, etc.) are valid, or that certain conditions for borrowing a vehicle are fulfilled (for example the maximum number of allowed borrowings or a maximum authorized mileage has not yet been reached by the user). The reference makes it possible to identify the subscription of the user among all the subscriptions for which information is stored in the database  31  of the server  30 . 
     When the vehicle  40  receives an authorization for access to the vehicle  40 , the control unit  43  of the vehicle  40  sends for example a command for deactivating an anti-theft device of the vehicle  40 . The anti-theft device is for example configured to lock the steering column of the vehicle  40  when it is activated. 
     It is thus clear, as illustrated in  FIG. 2 , unlike the solutions of the prior art, that there is no need to establish a direct communication link between the terminal  50  and the server  30  at the moment when the user wishes to access the vehicle. In the solution proposed, the vehicle fulfils a role of intermediary (a role of proxy) between the terminal  50  and the server  30 . 
     The solution proposed is thus simpler to implement since it does not require establishing communication between the terminal  50  and the server  30 . 
     Furthermore, the solution proposed is potentially less expensive for the user, in particular if the user is in a situation of roaming in a foreign country. This is because, when a free ad hoc communication link  61  that does not use an infrastructure is used between the terminal  50  and the vehicle  40 , the user does not have any communication cost to bear. The cost related to the communication link  71  between the vehicle  40  and the server  30  can in fact be borne by the manager of the vehicle-sharing service. 
       FIG. 5  schematically shows the main steps of a method  100  for access to a vehicle  40  of a vehicle-sharing system  20  according to the invention. 
     The various steps of this method  100  are for example implemented by the server  30 , the vehicle  40  and the terminal  50  of the vehicle-sharing system  20  described previously with reference to  FIG. 2 . 
     The method  100  includes in particular the following steps:
         an identification  101  of the vehicle  40  by the terminal  50  from a local database  52  of the terminal  50 , said local database  52  including a list of vehicles likely to be used by the user and, for each vehicle  40  in the list, information making it possible to establish a communication between said vehicle  40  and the terminal  50  on the first communication link  61 ,   a pairing  102  between the terminal  50  and the vehicle  40  on the first communication link  61 ,   a sending  103 , by the terminal  50 , to the vehicle  40 , on the first communication link  61 , of a reference to the subscription of the user to the vehicle-sharing service,   a transmission  104  of said reference by the vehicle  40  to the server  30  on the second communication link  71 ,   a verification  105 , by the server  30 , of the subscription information of the user present in the database of the server from the transmitted reference,   if the verification  105  succeeds, a sending  106 , by the server  30 , to the vehicle  40 , on the second communication link  71 , of an authorization for access to the vehicle  40  in order to remotely allow the user to access the vehicle.       

     Optionally, the method  100  may also include a sending by the vehicle  40  of a confirmation to the terminal  50  if the access to the vehicle is authorized. This step is however not essential since an indication that the access to the vehicle is authorized may be visible directly on the vehicle. This step is not shown in  FIG. 5 . 
     As explained previously, it is important to note that, at the moment when the user wishes to access a vehicle, the identification  101  of the vehicle  40  by the terminal  50  from the local database  52  of the terminal  50  is made autonomously by the terminal, without there being an interaction between the terminal  50  and a remote server. 
     In particular embodiments, the method  100  furthermore includes a prior step of loading onto the terminal  50  of the local database  52 . The local database  52  can store the list of all the vehicles of the vehicle-sharing service, whatever the geographical position of the vehicles. According to another example, the local database  52  can be associated with a particular geographical area in which the vehicles in the list stored in the local database  52  are located, and to which the user expects to go. 
     A message-sequence diagram  200  representing an example of concatenation of the steps of a method  100  for access to a vehicle  40  of a vehicle-sharing system  20  according to the invention is illustrated in  FIG. 6 . 
     As illustrated in  FIG. 6 , an identification message  201  is for example sent recurrently by the vehicle  40  to a terminal  50  of a user of the carshare service. The identification message  201  contains in particular an identifier of the vehicle  40 . 
     The terminal  50  decodes the identification message  201  and, if a vehicle associated with the identifier contained in the identification message  201  is found in the local database  52  of the terminal  50  (identification step  101 ), the terminal  50  sends an authentication message  202  to the vehicle  40 . The authentication message  202  contains for example an authentication key associated with the vehicle  40  identified and stored in the local data base  52 . 
     The vehicle  40  verifies the authentication key and, if the verification succeeds, it sends an authentication confirmation message  203  (the set formed by the authentication message  202  and the authentication confirmation message  203  corresponds to the step  102  of pairing between the terminal  50  and the vehicle  40 ). 
     The terminal  50  is then in a position to send to the vehicle  40  an access request message  204  containing a reference to the subscription of the user to the vehicle-sharing service (sending step  103 ). 
     The vehicle  40  then transmits said reference to the server  30  in a new access request message  205  addressed to the server  30  (transmission step  104 ). 
     The server  30  verifies the subscription information of the user stored in the database  31  of the server  30  (verification step  105 ) from the transmitted reference. If the verification succeeds, the server  30  sends a message  206  of authorization of access to the vehicle  40  (sending step  106 ). Reception of the access authorization message  206  triggers the unlocking of an anti-theft system of the vehicle  40 . 
     Optionally, the vehicle  40  may send a confirmation message to the terminal  50  if access to the vehicle is authorized. This message is not shown in  FIG. 6 . 
     In  FIG. 6 , the messages  201 ,  202 ,  203  and  204  exchanged between the terminal  50  and the vehicle  40  are exchanged over the first communication link  61 . The messages  205  and  206  exchanged between the vehicle  40  and the server  30  are exchanged over the second communication link  71 . 
     The above description clearly indicates that, through its various features and the advantages thereof, the present invention achieves the objectives set. In particular, the procedure for access to a vehicle of a carshare service proposed by the invention is both simple and advantageous in terms of communication cost for a user.