Patent Publication Number: US-2012038489-A1

Title: System and method for spontaneous p2p communication between identified vehicles

Description:
BACKGROUND OF THE INVENTION 
     Many vehicles which travel on the roads are equipped today with one or more mobile communication devices, such as cellular mobile phones, global positioning system (GPS), wireless network transmitter/receiver, satellite based phones, etc. When traveling, either along highways, country side roads or off-road, there may be required an ability to spontaneously initiate a call to a nearby other vehicle the identity (or calling number) of its driver or of the built-in mobile communication device are unknown to the call initiator, based on substantially only an outside visible identity details, such as the model of the vehicle, the color of the vehicle, the vehicle&#39;s license plate number, etc. 
     SUMMARY OF THE INVENTION 
     The present invention may comprise a system installed on a vehicle comprising a processor comprising a memory unit to store a set of visible identification signs associated with said vehicle and calling details for calling said vehicle, a short range communication unit to enable participation in ad-hoc communication network, a display unit and input means, wherein said communication unit is adapted to transmit indication of said visible identification signs to other participants in said ad-hoc communication network. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which: 
         FIG. 1  is a schematic illustration of a group of vehicles during motion with communication between some of them, according to embodiments of the present invention; 
         FIG. 2A  which schematically illustrates communication system installed in a vehicle for enabling spontaneous communication of a driver of the vehicle with a driver of another vehicle, according to embodiments of the present invention; 
         FIG. 2B  which schematically illustrates a plurality of vehicles, each is equipped with a communication system according to embodiments of the present invention; 
         FIG. 3A , which schematically presents a screen of the display of a communication system, according to embodiments of the present invention; 
         FIG. 3B  which schematically presents another screen of the display of the communication system, according to embodiments of the present invention; and 
         FIG. 4  is a schematic flow diagram of communication initiation and maintaining according to embodiments of the present invention. 
     
    
    
     It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. 
     DETAILED DESCRIPTION OF THE PRESENT INVENTION 
     In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention. 
     A driver traveling in a car may be interested to communicate with a driver of a nearby other vehicle, for example for warning the other driver from an obstacle on the way, for receiving update of a traffic jam the other driver may have noticed, or any other reason. However, usually a traveling driver does not know how to contact another driver if the number of the mobile phone (such as a cellular phone) of that other driver is not known to him by chance. Usually a second vehicle in short a distance from a traveling first driver may be identified by the first driver by one or more visible signs. The short distance may be, for example, a distance enabling the traveling driver of the first vehicle to identify one or more details of the second vehicle from a list of visible identifying details, such as the color of the vehicle, the vehicle&#39;s model, the vehicle&#39;s production year, the vehicle&#39;s license plate string of characters, etc. At least some of the vehicles may be equipped with a mobile communication transceiver, such as a cellular phone, a Bluetooth transceiver, wireless local area network transceiver, such as a wireless network operating based on IEEE 802.11 standard, such as wireless fidelity (WiFi) wireless network of WiFi Alliance ®, and the like. According to embodiments of the present invention two or more vehicles being in a distance between them which allows establishment of an ad-hoc local area communication network and further allows perception of visible identification signs of one vehicle by the driver of the other vehicle may establish an ad-hoc local area communication network between them. 
     Reference is made now to  FIG. 1 , which is a schematic illustration of a group  10  of vehicles during motion with communication between some of them, according to embodiments of the present invention. Group  10  of vehicles may comprise a variable number of members. Group  10  depicted in  FIG. 1  consists of vehicles  22 A- 22 G, however, since the membership in group  10  is spontaneous and based on the momentary and dynamic nature of traffic, group  10  of vehicles may comprise, at any given time, smaller or larger number of members. At least some members in group  10  may be equipped with transceiver enabling the engagement to a wireless ad-hoc network, such as Wireless Fidelity (WiFi) of WiFi Alliance, Worldwide Interoperability for Microwave Access (WiMax) based on the IEEE 802.16 standard, ZigBee based on IEEE 802.15.4 standard, etc. where the network has the capability to recognize newly joined members based on the protocol and add them automatically. The wireless ad-hoc communication network according to embodiments of the present invention may be of a kind limited to relatively short ranges. For example, the range of a wireless ad-hoc network according to embodiments of the present invention may be limited to a range which still allows a driver of one of the group&#39;s vehicles to perceive visible identifying (VID) indications of another vehicle in the group, for example—about 150-200 meters in case when the color and model of the other vehicle are to be perceived, and about 100 meters or less if the license plate writing is to be perceived. 
     As presented in  FIG. 1 , vehicles  22 A,  22 B,  22 C and  22 F may be engaged in a wireless ad-hoc communication network  24 , while vehicles  22 D,  22 E and  22 G are not engaged in this wireless ad-hoc communication network. The imaginary circle  50  drawn around vehicle  22 B exemplifies a range measured from vehicle  22 B within which the driver of vehicle  22 B may have visible perception of certain VID indications of vehicles around it. It will be apparent to a person skilled in the art that this range may vary, depending upon factors such as the driver&#39;s vision, visibility conditions, noticeability (such as level of contrast of the ID sign versus the background), etc. Further, the shape of the closed line encircling the area in which a driver of vehicle  22 B may perceive VID signs of other vehicles around him may be other than a circle, mainly due to the changes in visibility around the vehicle compared to the visibility in the looking-forward sector, and possibly due to other factors. For example, a driver may have lower visibility at the back of the vehicle compared to that of the looking-forward. 
     Reference is made now to  FIG. 2A , which schematically illustrates communication system  201  installed in a vehicle  200  for enabling spontaneous communication of a driver of vehicle  200  with a driver of another vehicle, according to embodiments of the present invention. Communication system  201  may comprise a short range communication unit  204 , capable of engaging and participating in a wireless ad-hoc communication network as described above, in ranges of at least 200 meters; display  210  for presenting data to a user, such as the driver of vehicle  200 ; input means  212  enabling the user to input data and/or commands to communication system  201 ; and processor  220  with memory  221  to control the operations of communication system  201 . Processor  220  may be a CPU, a controller or any other device capable of executing programs for performing the functions of communication system  201 , of communicating with peripheral devices such a storage device (not shown) and of communicating with short range communication unit  204 , with mobile phone interface unit  206 , with display  210  and with input means  212 . According to some embodiments of the present invention display  210  and input means unit  212  may be realized in one physical unit, such as a touch screen. Mobile phone interface unit  206  is adapted to communicate with mobile phone  207 , initiate a call to a selected phone number provided by, or pointed at by interface unit  206 , hold a call, deny an incoming call, etc. 
     Communication system  201  may is uniquely associated with VID signs  202  of vehicle  200 . VID signs unit  202  is a general definition for a set of available visible ID signs that vehicle  200  has. While most (if not all) vehicles have certain visible ID features such as color, manufacturer model, license plate characters string, etc., some of these vehicles may have additional/other visible signs such as a decorative spoiler, roof rack, rear bike carrier and the like. Some of the vehicles may also be equipped with short range communication unit capable of engaging and participating in wireless ad-hoc communication network. According to embodiments of the present invention VID signs  202  of vehicle  200  are stored in a storage means in communication system  201  and may be transmitted to other participants of the wireless ad-hoc communication network. For example: vehicle  200  has VID signs  202  set such as red color, manufactured by Chevrolet® with license plate string “ABC 123”. These VID signs  202  are uniquely associated with communication system  201  of vehicle  200  and their description is stored in system  201 . According to embodiments of the present invention another vehicle participating in wireless ad-hoc communication network with which communication system  201  is engaged will receive an indication that a red Chevrolet® vehicle with a license plate reading “ABC 123” is currently a member of the wireless ad-hoc communication network. 
     A mobile phone  207  of vehicle  200 , or of a driver of vehicle  200 , may be associated with and in active communication with communication system  201 , for example via mobile phone interface unit  206 . In some embodiments mobile phone  207  may be part of communication system  201 . 
     Reference is made now also to  FIG. 2B , which schematically illustrates a plurality of vehicles, each is equipped with a communication system  201 ,  201 A . . .  201 D, etc., according to embodiments of the present invention. These communication systems are installed in vehicles denoted  200 ,  200 A . . .  200 D, etc. respectively (not shown). Two or more vehicles may be engaged in wireless ad-hoc communication network  252 . Each vehicle which is linked into wireless ad-hoc communication network  252  transmits to all other participants its VID signs description as identified in VID signs  202  indications and recorded in the storage device of processor  220 . Each vehicle which is linked in wireless ad-hoc communication network  252  receives the ID indications of the other vehicles presently linked to wireless ad-hoc communication network  252 . The linked vehicles may be presented to a user of communication system  201  on display unit  210 . The indication of the other linked vehicles is done by presenting to the user the available VID details, such as, according to the example above, “Red Chevrolet, ABC 123”. User of communication system  201  may associate a set of ID details with a specific name SN and save this SN in the storage device of system  201 . Received VID details for which a SN is saved in the system will be presented to the user by presenting SN instead of, or additional to the set of VID details. For example, if user of communication system  201  has associated the name Dan with the ID details “Red Chevrolet, ABC 123”, then each time the communication system associated with these ID details, for example communication system  201 C, links to wireless ad-hoc communication network  252 , other members which are linked to that network will receive indication that communication system identified as “Red Chevrolet, ABC 123” is connected to the network, and communication system  201 C will also get indication that this communication system is identified as “Dan”. 
     As is depicted in  FIG. 2B , communication systems  201 - 201 D are adapted to initiate and maintain mobile phone connections, such as cellular connection, between two or more members of network  252 . For example, two or more of communication systems  201 - 201 D may communicate via a wireless telephone network  254 . This feature is discussed in details in connection with  FIGS. 3A and 3B . It will be noted that in case mobile phones  207 ,  207 A, etc. support establishment of conference call between them, mobile interface unit  206  will be adapted to establish and administer that conference call when needed. 
     According to some embodiments wireless ad-hoc communication network may provide indications of relative distance between members in the network, and according to additional embodiments it may also provide indications of relative direction between members in the network. System  250 , by means of relying on Global Positioning System (GPS) information or on TOA (Time of arrival) techniques using, for example, parallel transmissions in two different frequencies, may calculate the distance of another member in network  252  from the vehicle of systems  201 . According to embodiments of the present invention vehicle  200  may use an antenna having multi-directional resolution capability to enable receipt of indications of the relative direction form which a transmission from another member in the ad-hoc network is received. When both relative or absolute distance and relative or absolute direction between vehicle  200  with system  201  and another member linked to ad-hoc network  252  are available, the location of the other member or members, in absolute or relative notations may be calculated and used, for example, for presenting to the user of system  201 . 
     The information transmitted from one member of ad-hoc network  252  to other member or members may include location indication, such as geographical coordinates that may be received from a GPS receiver which is in active communication with system  201 , and the like. Location information of members in ad-hoc network  252  may be used to graphically present the relative location of other members with respect to the location of vehicle  200  (with system  201 ) on display unit  210 . According to embodiments of the present invention this information may further be parsed to deduct and present, for example on display unit  210 , relative movement of the other members in ad-hoc network  252  with respect to vehicle  200 . Further, system  201  may analyze these relative movements and identify specific movements of special interest to the user of vehicle  200 , such as movements with high probability to cause an accident. System  201  may have stored in its storage device envelopes of distance, relative direction and closing speed which may represent high risk of accident and may further issue warnings to the user when a risky situation is evolving. According to yet other embodiments of the present invention system  201  may disregard, for the sake of issuance of alarms, member vehicles traveling in direction opposite to that of vehicle  200  for example on roads having barrier between the lanes of the separate travel directions because on such roads approaching vehicle may, most probably, be traveling on a lane on the other side of the bather and thus imposing no risk. Collision alerts may be issued when the combination of distance and closing speed and direction between user of vehicle  200  and another vehicle member exceeds a defined threshold, such as the “2 seconds” threshold applying to a minimum distance that leaves at least two seconds for the driver to react in emergency braking situation. 
     Reference is made now to  FIG. 3A , which schematically presents screen  50  of display  210  of communication system  201 , and to  FIG. 3B  which schematically presents screen  52  of display  210  of communication system  201 , according to embodiments of the present invention. Screen  50  may comprise two main display areas  50 A and  50 B. Display area  50 A may be used to graphically present location information related to members who are currently linked to communication network  252 , relatively to the location of a graphical representation of vehicle  200  of the user. Members who are linked to ad-hoc communication network  252  may have one or more of several features, such as: members identified by their name, members supporting indication of relative distance, members supporting indication of relative direction, members whose request to establish a phone call with vehicle  200  was refused, members who are in active phone connection with the user of vehicle  200 , etc. Some of these features may be graphically presented on screen  50 A, as will be discussed below. Display screen  50 A may present icon  302  which graphically represents vehicle  200  ( 22 B of  FIG. 1 ) of the user of system  201 ; icon  304  may graphically represent vehicle  22 A of  FIG. 1 ; icon  306  may graphically represent vehicle  22 C of  FIG. 1 , icon  308  may graphically represent vehicle  22 E of  FIG. 1  and icon  310  may graphically represent vehicle  22 F of  FIG. 1 . Icons  304  and  306  may have different appearance then icon  302  and may be used to graphically present vehicles for which a SN is associated with their respective VID signs and is saved in system  201 , for example “Bob” and “Dan” respectively. Accordingly, the SN “Bob” and “Dan” will be presented in association with the icon on screen  50 A representing the respective members in ad-hoc network  252 . In some embodiments the written description of the VID signs of the vehicles of Bob and of Dan may also be presented next to their SNs. Icon  308  may have yet another visible feature to represent the fact that it&#39;s distance from vehicle  200  of the user is beyond the distance enabling to identify its VID signs, in case communication system  250  supports measurement of distances. The distance governing this feature may be definable by the manufacture of system  201  and/or by the user of system  201 . According to embodiments of the present invention this threshold distance may vary according to the relative angle of line of sight from vehicle  200  to the vehicle represented by icon  308 , by visibility conditions, etc. Icon  310  may have yet another visible feature to represent a vehicle participating in wireless ad-hoc communication network  252  but its visible ID signs are not associated with any SN saved in system  201 . It would be noted that in display  50 A some visible features are exemplified using different types of lines other visible features may be used, such as color of the icon, color of the fill of the icon, and the like. 
     When system  250  supports obtaining distance and direction between participating vehicles, the location of icons representing participating vehicles on display area  50 A of screen  50  with respect to icon  302  may be representative and correlative to the distance and direction of the respective vehicles with respect to vehicle  200 . Icon  302  may be presented substantially in the middle of display area  50 A, or at any other desired location, such as is the case in  FIG. 3A , where icon  302  is presented substantially at ⅓ of the height of display area  50 A from the bottom and slightly to the right of the middle of width of display area  50 A, to represent travel on a right lane. According to embodiments of the present invention several presentation modes may be used, such as “nose-up” in which the location and orientation of icon  302  in display area  50 A is fixed and other graphical icons and other graphical data, e.g. moving map (when supported) will be moved and/or panned accordingly; “north-up” in which icon  302  may be located in the middle of display area  50 A and its orientation is changed on the screen to represent the deviation of the direction vector of movement of vehicle  200  from the North, etc. When system  250  does not support indications of distance and direction between participating vehicles, their respective icons may be presented in display area  50 B, for example as a list comprising VID descriptions  312  and  314  in any desired order and manner, with respect to each other. 
     Display area  50 A may further present a calculated border line  320  vehicles which are presented on the far side of it from icon  302  are supposed to have poor connection on ad-hoc network  252 , or none at all. Display screen  50  may be designed to reflect, similarly to “traditional” radar screens, the relative location and speeds of vehicle  200  represented buy icon  302  with respect to other vehicles currently engages in communication on ad-hoc network  252 . Changing the content displayed on the screen may be done by pressing on “Menu” soft key  362 , in case display  210  is a touch screen, or on a dedicated hard key close to the screen. Pressing this button will change the display and functionality of the screen from graphical presentation of the relative location of vehicle  200  to neighboring vehicles (the “Radar” screen), to presentation of functional screen  50 B, as depicted in  FIG. 3B . Switching from Display screen  50  to  52  may be done manually by pressing “Menu” button  362  or automatically, in response to a triggering event. A triggering event may be, for example, an incoming phone call. 
     When the display of system  201  is in the “Radar” display mode, as depicted in  FIG. 3A , and the user in vehicle  200  wishes to initiate a phone call with one of the vehicles participating in wireless ad-hoc communication network, he may simply touch the icon on display area  50 A associated with that vehicle. If the vehicle with which the user wishes to initiate a call is not associated with a SN, the user may identify that vehicle by the list of VID signs available to system  252  which are presented next to the icon of that vehicle. This feature actually allows a driver of a first vehicle to initiate a call to a driver of a second vehicle within the reach of his sight, based only on outside VID signs of the second vehicle, without needing to know who drives that second vehicle or what is his/her mobile phone number, as long as the second vehicle has linked to the wireless ad-hoc communication network and his communication system for participating transmits the VID signs of its vehicle. According to embodiments of the invention the user may initiate a call to a participating vehicle simply by pressing on the graphical symbol of that vehicle on his screen, or by pressing/activating a respective input means. It will be appreciated by a person skilled in the art that for supporting this feature of spontaneously calling a participating vehicle there is no need for an external database which stores tables of potential participant vehicles and their respective mobile phone numbers, or nay other external database. System and method of the present invention enable initiating a call to a completely stranger vehicle based solely on the external visible ID signs of that vehicle. 
     Display screen  52  may be used for the presentation, activation and administering of functions, warnings and other interface items of system  251  with the user and with other vehicles currently engaged in ad-hoc network  252 . Display screen  52 , and if necessary display screens that are accessible via display screen  52  (not shown), may enable display, activation and control of phone calls and specifically incoming calls. When a user in a vehicle engaged in ad-hoc network  252  calls system  201  the user in vehicle  200  may handle the call via function buttons located in portion  53  of display screen  52 . The switching from “Radar” screen  50  to display screen  52  may be carried out automatically or manually, as described above in details. When display screen  52  is activated an incoming call will be indicated by the displaying of CAR CALLS icon  354  along with ID of the calling member of the ad-hoc network. When the calling member is a known user in system  201  and has been accorded a SN, his or her SN will be displayed. The appearance of icon  354  when a call is incoming may be just the presentation of the icon with the ID details/SN, yet other visual attributes may be used to attract the attention of the user, such as the icon will flash or will cyclically change colors, etc. The user of system  201  may accept the call by pressing on icon ‘ACCPT CALL’  356  or reject the call by pressing on icon ‘RJCT CALL’  354 . According to embodiments of the present invention the user may mark a caller as one that calls from him should always be rejected, for example by pressing on icon ‘RJCT CALL’  354  repeatedly twice. According to embodiments of the present invention such action may be confirmed by system  201 , for example by presenting a confirmation notice on screen  210  for few seconds, or may require a confirmation prior to permanently blocking calls from that caller. 
     The user may also establish a conference call with the calling member and other phone users by pressing on icon ‘CONF CALL’  364 , which in turn may open in portion  57  of display screen  52  a list of phone users available for the establishment of the call (not shown), from which the user may pick one (or more, depending on the phone conferencing abilities) members/users for connecting them to the call. The user in vehicle  200  may further alert other members currently engaged in ad-hoc network  252  that he/she are in, or about to enter, an emergency situation, by pressing on icon ‘SOS’  360 . This may initiate an immediate call to one or more of emergency services such as the police, fire squad, medical emergency service, and the like. According to some embodiments the transmission to a public emergency service may comprise transmission of momentary location, for example taken from a GPS unit, and/or the VID details. Further, pressing on icon ‘SOS’  360  will activate transmission to the members that will force presenting an icon representing vehicle  200  on their screens, with indications of direction and distance between vehicle  200  and the respective other vehicle (when available) and a writing that vehicle  200  has transmitted ‘SOS’ indication. According to embodiments of the present invention when indication of distance/direction between vehicle  200  and the respective other vehicle is available system  201  of the respective vehicle will enforce switching to display screen  50  (“Radar” screen”) and then will display the icon of vehicle  200  relatively to the icon of the respective other vehicle, to graphically display to the user the relative position to vehicle  200  who signals ‘SOS’. Based on the ability of system  200  to create or join a network, one can establish an SOS massage on base frequency that will burst to all members that are in a listening radius. For example, the 455 MHz that is in use to transmit SOS massage from ships that are in distress. 
     In order to control the various functions effecting how information is displayed to the user icons controlling the display modes located in area  55  of display screen  52  may be used. The user may set various display parameters of the “Radar” screen  50  by pressing icon ‘RDR SCREEN SETUP’  372 , which may switch to another display screen (not shown) enabling to set one or more of the following features: enabling/disabling presentation of vehicles traveling the opposite direction; setting the distance at which disconnection of communication within ad-hoc network  252  is expected (as graphically represented by line  320 ), presenting/removing display of moving map along with other graphical elements; setting mode of displaying of graphical elements in 2D/3D (as is known with many commercially available GPS-based moving maps built into road maps); setting mode of displaying to day/night compatible colors selection, etc. Further, the user may be able to define a group of vehicles, by their VID signs or by their given SN, which will not be presented on the screen unless any one vehicle of this group has been identified as approaching the user&#39;s vehicle in risky trajectory, at which situation its graphical presentation will be enforced. Similarly the user will be able to define a group of vehicles that will be presented on the screen whenever their system is engaged in ad-hoc network  252 . 
     According to embodiments of the present invention user of system  201  may further set the parameters of display on the screen via setting functions available via icon ‘USERS DISP SETUP’  374 , which allows defining the ‘black list’ and/or ‘white list’ of vehicles which will never be served/responded by system  201  or that will always be attended to by system  201 , respectively. Further setting is available when pressing icon ‘THRESHOLD SETUP’  376 , which allows setting thresholds such as how close can vehicle  200  get to a vehicle in front of it when the “too close” warning is triggered. While the nominal value is commonly set to “the distance vehicle  200  travels in 2 seconds in the current speed”, the user may wish to expand this value in order to get earlier warning. In some embodiments of the invention the warning may be turned ON based not only on the distance but also on the relative direction between the user&#39;s vehicle and the other vehicle and further based on the rate of getting close. Another threshold that may be set is the threshold indicating ‘about to be disconnected from ad-hoc network’. 
     Area  57  of screen display  52  enables the user of system  201  to manage a list of vehicles/users already known and recorded, similarly to the management of a list of contact people in the memory of a phone device. By pressing icon ‘ADD/MOD USERS’ 382 the user may add, edit and remove details of other vehicles, accord them a SN and add a realistic image/photo that will be displayed as an icon of that vehicle when it is presented on the screen. Alternatively, system  201  may store a representative graphical icon for certain car manufacturers or car models, which will be used for presenting the respective vehicle on the display. Via this list it is also possible to add attendees to a conference call. By pressing icon ‘LISTS MANAG’  384  the user may manage lists, or groups of users/vehicles. For example, managing ‘black lists’ and/or ‘white lists’, as explained above in details. 
     When the user of system  201  wishes to switch from MENU screen  52  to RADAR screen  50  he/she may press on ‘RADAR SCREEN’ button  361 . 
     It will be apparent to those skilled in the art that the description of the various functionalities and the way of activating them, as described above, relates to an embodiment where display  210  and input means  212  are embodied in one device, such as a touch screen. However, the same or similar arrangement may be utilized when display  210  and input means  212  are embodied separately, to realize the functionalities and operational modes described above without departing from the spirit of the invention. 
     According to embodiments of the present invention when a vehicle approaches a controlled gate, that gate may be opened for approved vehicles when that vehicle gets close enough, as that vehicle is made known to the controlled gate based on the visible ID signs of the vehicle which may be transmitted to the gate via a temporary wireless ad-hoc network in which both the gate and the approaching vehicle are members. 
     According to embodiments of the invention operation of the user-system interface may be carried out, fully or partially, using voice commands and voice response, to improve safety of the use of the system. 
     According to embodiments of the invention the entering of the visible ID signs into the system may be done only by approved services, to prevent fraud. 
     According to embodiments of the invention system  201  may be used for sending alarm signals when the vehicle is stolen, and may assist in spotting the vehicle when it was stolen. 
     According to embodiments of the invention when the vehicle is linked to a wireless ad-hoc communication network several data items may be provided to system  201  such as availability of parking spaces, availability of other services, based on the location of the vehicle. 
     According to embodiments of the present invention system  201  may issue a signal to vehicle  200  that is indicative of a closely upcoming need for braking, for example when vehicle  200  is too close to a vehicle in front of it and is approaching that vehicle with a too high speed. In such situation that signal may be used for lighting the rear brake lights slightly before the driver of vehicle  200  touches the brake pedal (or any other braking means) and thus provide an anticipating signal that may enhance the driving safety. 
     According to embodiments of the present invention data saved in system  201  that may be of interest to legal authorities, such the police may be made available to these authorities under the local binding laws and regulations pertaining to protection of privacy and possibly other restrictions. According to yet another embodiment system  201  may be programmed to enable a vehicle belonging to an enforcing force, such as police, to initiate a call to system  201  so that the user of system  201  may not reject or block the call. This feature may be useful when a police car is chasing a law-breaking vehicle and it is required to let the user of the chased vehicle to know that he/she are instructed to stop the vehicle and pull over. According to this embodiment memory  221  of system  210  may store a list of such law-enforcing vehicles that are allowed to initiate such a break-through call. 
     According to embodiments of the present invention system  201  may be set, when vehicle  200  is not in use, to a ‘theft alarm’ mode. When in that mode system  201  may transmit, intermittently, a signal to a receiver next to the owner of vehicle  200 . Said signal may be used to identify, for example based on Doppler Effect, movement of vehicle  200  and thus to trigger a theft alarm. 
     Reference is made now to  FIG. 4  which is a schematic flow diagram of a method initiating and maintaining a call with a nearby vehicle based on the visible external ID signs of that vehicle, according to embodiments of the present invention. First, the user identifies a nearby vehicle relying on the VID signs of that vehicle (block  402 ). Then the user issues a request to establish a car-to-car call to that vehicle (block  404 ) by sending a call request to that vehicle by means of pressing a button associated with that vehicle in the user&#39;s screen area  50 A. When an authorization from the called vehicle is received the call takes place and respective indication is displayed on the screen (block  46 ). Finally when the visible signs of the called vehicle are associated with a SN stored in the calling vehicle system, that SN will be presented next to the graphic (or other) representation of the called vehicle (block  408 ). 
     While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.