Patent Publication Number: US-6911918-B2

Title: Traffic flow and route selection display system for routing vehicles

Description:
BACKGROUND OF THE INVENTION 
   This invention relates generally to a traffic information display system that facilitates choosing a route for a vehicle and, more specifically, this invention relates to a system for displaying in color-coded visual format, on board a vehicle, information concerning the rate of flow of traffic on routes surrounding the vehicle. The system of the invention is particularly useful for users directing a land vehicle toward a given destination wherein a variety of routes may be available for such travel, but traffic conditions on one or more alternate routes may be more favorable than on others. 
   At present, many forms of traffic sensors and display systems are known. In the known systems, sensors are positioned along roads and set up to transmit information signals concerning traffic flow conditions. The transmitted signals are received at various locations where the information they represent is recorded and/or processed for further use. Some of the existing systems for processing or using such vehicular traffic information also make use of signals transmitted by the satellite-based Global Positioning System (G.P.S.). Some known display systems make use of stored signals for displaying road map representations of selected geographic areas. 
   However, none of the existing road and traffic reporting/display systems are known to provide real-time displays of current traffic conditions along selected and alternative routes in an area surrounding a vehicle. Existing systems are not known to include any provision for visual displays of traffic speed information that is specific to routes between the vehicle location and a destination selected by the user. And further, existing systems are not known to provide in any form, for identifying alternate routes that are preferable based upon comparative traffic speed conditions and/or travel time to a given destination. 
   SUMMARY OF THE INVENTION 
   The present invention provides a method and apparatus for allowing an operator to direct a vehicle toward a selected destination, talking into consideration relative traffic conditions on available routes. The invention employs spaced-apart traffic sensor monitors positioned at intervals along established travel routes, the monitors being capable of sensing traffic speed conditions separately for each direction of travel, and transmitting representative signals to another location. Combined or separate sensors may be employed for each travel direction. Groups of monitor sensors within geographic locales, identified as “sections”, are associated with section stations. 
   Each section station embodies a receiver for receiving traffic condition signals in sequence from each monitor sensor station within the associated geographic section, a data processor for processing traffic condition signals reported by the monitors, and a transmitter for transmitting processed traffic information signals to vehicles within the geographic section served by the section station, The processor in a section station may be programmed to recognize the average speed of reported traffic within a section or monitored portions of a section, and to assign a color codes to average speeds within predetermined ranges. Alternatively, color-coding signals for each individual route portion or section may be created and then transmitted from within each monitor station or color coding may be created within each vehicle station. Those skilled in the art will recognize that it will generally be preferable to perform color coding assignment early in the transmission sequence, to reduce the complexity and density of the transmitted information signals. 
   An optional central processing station also be provided to receive traffic condition information signals from the various section stations. The central processing station stores a database of additional information such as wide area road maps that can be transmitted selectively to one or more vehicles, together with traffic information received from various section stations in other geographic areas within the range of the central station. Transmissions from the central station to a particular vehicle are sent in response to an interrogation signal from a vehicle, so as to provide vehicle operators with optional information not otherwise available from the section stations and the database unit on board a vehicle. 
   In accordance with the invention, a mobile receiving station in a vehicle receives signals from the section stations and, optionally, from the optional central stations. The vehicle station incorporates a conventional GPS navigational display device which includes a database unit containing map display data for areas surrounding the vehicle receiving station, and a visual display unit capable of displaying selected map with road sections displayed in predetermined colors corresponding to traffic speed conditions reported by the monitors on those routes. In operation, the system of this invention utilizes existing GPS methods and the data signals that are routinely transmitted by the GPS to mark the position of a corresponding vehicle station on the displayed local area road map. This technology is well-known at this time. The system further uses similar information derived from the GPS to highlight a “preferred” route from the vehicle station&#39;s location to an identified given destination. The “preferred” route is determined in accordance with known GPS technology based at least in part upon distance and travel time data for given road sections that are available within the GPS system. 
   In a further embodiment of the invention, a vehicle station may access relevant information downloaded from a remote source such as a portable computer. This permits a user of the invention to display or otherwise utilize information not readily available from GPS data banks or from memory units incorporated into the system of the invention. 
   Accordingly, it is an object of this invention to provide an on-board traffic reporting and display system for vehicles, that offers to vehicle operators a display of routes surrounding the vehicle where the speed of current travel on each route is identified by visual indica. 
   Another object of the invention is the provision of a traffic reporting and display system that employs color coding to identify average traffic speed conditions on different available routes between a vehicle and a selected destination. 
   Still another object of this invention is the provision of a traffic system for vehicles that offers users a choice of alternate routes based upon the rate of traffic flow on each possible route. 
   Another and further object of the invention is the provision of a color-coded traffic flow reporting and display system that interacts with publicly available global positioning system [GPS] data to mark the location of a vehicle on a displayed road map. 
   Still another and further object of the invention is the provision of a traffic reporting and display system that employs algorithms for: collecting real-time traffic speed data; selecting map displays in response to signals received into the system; and determining the color-coding that will be applied to sections of displayed routes in accordance with reported traffic information signals for pre-determined portions of those routes; and 
   Yet another and further object of the invention is the provision of a real-time traffic reporting and display system that employs color-coding to identify traffic speed conditions, and permits users to associate frequently used destinations with predetermined selection signal devices such as dedicated push buttons, so as to facilitate the display of appropriate possible routes to those destinations. 
   These and still other and further objects, features and advantages of this invention will be made apparent to those having skill in this art by the following description considered together with the accompanying drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram of a monitor station in accordance with this invention; 
       FIG. 2  is a block diagram of a section station in accordance with this invention; 
       FIG. 3  is a block diagram of a vehicle station in accordance with this invention; 
       FIG. 4  is a sequence diagram illustrating the operation of an algorithm for use in a monitor station in accordance with this invention; 
       FIG. 5  is a sequence diagram illustrating the operation of an algorithm for use in a section station in accordance with this invention; 
       FIG. 6  is a sequence diagram illustrating the operation of an algorithm for identifying an alternate preferred route in accordance with this invention; 
       FIG. 7  is a sequence diagram illustrating the operation of an algorithm for use in a vehicle station in accordance with this invention; 
       FIG. 8A  is a sequence diagram illustrating the first part of the operation of an algorithm for assigning color codes to monitored routes in accordance with this invention; 
       FIG. 8B  is a sequence diagram illustrating the second part of the operation of the algorithm of  FIG. 4 ; 
       FIG. 9  is a block diagram symbolic representation of the interface between a vehicle station and a GPS navigation unit in accordance with this invention; 
       FIG. 10  is a block diagram representation of a central station for use in conjunction with the system of this invention; 
       FIG. 11  is a simplified diagrammatic representation of a visual display unit incorporating optional features used in a vehicle receiving station in accordance with this invention; 
       FIG. 12  is a block diagram representing an overview of a traffic display system in accordance with this invention; 
       FIG. 13  is a sequence diagram illustrating the operation of an optional algorithm for automatically disabling a route that has been selected automatically in accordance with this invention; 
       FIG. 14  is a sequence diagram illustrating the operation of an optional algorithm for automatically enabling a route that has been disabled in accordance with the algorithm of FIG.  13 . 
       FIG. 15  is a sequence diagram illustrating the operation of an algorithm for applying color codes to all of the monitored route sections on a route map display after the corresponding colors for each monitored section have been selected in accordance with FIGS.  8 A and  8 B. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the drawings, a monitor station  10  in accordance with this invention, as shown in  FIG. 1  may be seen to comprise a data collection device  12  of any suitable well-known design for receiving electronic traffic speed signals from a traffic monitoring sensor or transducer  18 , which also may be of any suitable type. The collection device  12  is connected to a microprocessor  14  capable of storing signals received by the collection device  12  and processing those signals to create data signals representative of the speed of traffic passing the monitor station  10 . 
   It should be understood readily by those skilled in the related art, that any of the signals referred to herein may be either analog or digital or, if desired, a combination thereof. In the event that a combination of such signals are used, a suitable analog/digital [A/D] converter device of readily available type may be incorporated into the system of this invention at any suitable point, to accommodate any necessary conversion from one type of signal to the other. 
   Microprocessor  14  of monitor station  10  is coupled in turn to a data transmission unit  16  which transmits signals from microprocessor  14  to a section station  20  as shown in  FIG. 2 , via wire or wireless, in any well-known manner. As disclosed herein, each section station  20  receives traffic speed data signals from a plurality of separate, but associated, monitor stations  10 . The monitor stations  10  are installed at substantially uniformly spaced-apart locations along existing vehicular routes within a given geographic section. Each section station  20  incorporates a receiver unit  22  (for receiving traffic-speed data signals transmitted from each associated monitor station  10 ), a microprocessor unit  24  (for processing the signals received by receiver  22 ), and a buffer unit  26 , interposed between receiver  22  and processor  24 , for assuring that received signals are maintained independently of each other so that they can be processed and identified independently of each other in processor  24 . In accordance with this invention, each section station  20  embodies a data transmission unit  28  for transmitting processed traffic information signals to vehicles within the geographic area served by the section station. Signals generated by transmission unit  28  also may be sent, via wireless or wire, to an optional central data processing station  30 , shown in FIG.  10  and further described below. For signal transmission from section stations to a central station, transmission via wire may be preferred when the transmission distances involved. 
   As shown in  FIG. 3 , vehicle station  40  in accordance with this invention embodies a vehicle receiver unit  42 , a vehicle microprocessor  44  coupled to the receiver  42  via a buffer  43 , a Global Positioning System (GPS) interface unit  46  coupled to the output of the microprocessor  44 , a visual display unit  48  (preferably a GPS display unit of any conventional type) coupled to the output of the interface unit  46 , and a map database unit  50  coupled to or incorporated as part of the display unit  48  to provide access to stored data representing road maps of the area served by a plurality of related section stations  20 . Interface unit  46 , display unit  48  and Further in accordance with this invention, vehicle station  40  incorporates a remote download interface unit  45  coupled to exchange data signals with processor unit  44 , and to receive signals from a device such as a portable personal computer [not shown] coupled to a serial port interface device such as remote download interface unit  47 , so that processor unit  44  can receive information from external sources concerning matters of importance to an operator of the vehicle. That is, the operator may wish to seek information concerning a route or routes between particular widespread points of departure and destination that are outside the area covered by one or more local section stations Accordingly, before an operator sets out on a vehicular trip, pertinent information may be downloaded into a portable computer and then from the portable into the system of this invention, using a remote download interface unit  47  as indicated in FIG.  3 . Those having skill in this art will recognize that each of the electronic data processing, storage and display units referred to herein may be of known design and function, and a variety of such units currently are available to carry out the independent functions or steps disclosed herein. 
   Optional central data processing station  30  in accordance with this invention, shown in  FIG. 10 , embodies a central station communications processor  33  for receiving traffic information signals from section stations  20  and such other external sources as may be desired. Central stations  30  may receive external interrogation signals as well, via access channels such as the internet, or cellular telephones or from a vehicle station  40 . Central Stations  30  further embody a central station processor  34  coupled to the communications processor/receiver  33 , and one or more central database storage units  36  for storing map and other information signals related to the wider area served by the central station. The central station periodically polls all section stations within the geographic area assigned to the central station to collect and store signals indicative of reported traffic conditions. The signals are stored in a pre-sorted scheme, for example according to road identification symbols, so that data for desired roads can be retrieved easily. In this regard, communications processor  33  is equipped to respond to external interrogation signals with information stored in and available from data storage units  36 . 
   In the operation of the system of this invention, each monitor station  10  transmits to its associated section station  20 , data signals representing the speed and direction of vehicular traffic passing that monitor station. The exact identity of the monitor station, corresponding to a particular portion of a particular route is either included in the signals transmitted by the monitor station to the section station, or this information is added automatically by the section receiver  22  or section processor  24  based on preset stored data. Further, the traffic speed information transmitted from each monitor station either represents the calculated average speed of the monitored traffic during a given time period or it represents raw speed data, in which case, average speed is calculated by processor  24  in section station  20 . 
     FIG. 4  displays the algorithm controlling the operation of each monitor station  10  in a system according to this invention where average speed is calculated within the monitor station and is then transmitted to the associated section station  20 . That is, in step  13  each monitor  10  collects traffic speed data from all lanes for N seconds, where N is any desired, predetermined time interval such as for example 30 seconds; the processor  14  of station  10  sums the speed signals and determines the average speed of traffic passing the station during the determined interval, step  15 , and then at the end of the cycle, transmission unit  16  transmits to the corresponding section station  20 , in step  17 , the calculated average speed together with identification of the source, including route identification and subsection identification as well as traffic direction, if needed. Following the completion of step  17  at the end of a cycle, monitor  10  returns to step  11  to begin repetition of its cycle of monitoring and reporting. 
   When the traffic speed and route identification data from each monitor station is received at the corresponding section station  20 , following completion of step  17  at each monitor station, the section station processes the received data packet in accordance with this invention. That is, in accordance with the algorithm shown in  FIG. 5  of the drawings, a section station  20  receives the sequential data packets from each associated monitor station  10  within its responsibility, in step  21 . The data packets are received from each monitor station in step  21  and are partially processed to assign corresponding color coding in step  23 , in sequence, until processor  24  determines that a report has been received from each monitor  10 ; at that point in time, the sequence of operations continues from step  23  to step  25 . In step  23 , each packet of data that is received in step  21 , is assigned a color code in accordance with the color code algorithm of  FIGS. 8A &amp; 8B , to be described later herein. Although color-coding of traffic speed data is described here as being determined within the apparatus of section station  20 , those with skill in the art will recognize that performing this function within section station  20  is largely a matter of choice. It is entirely possible to perform the color-coding function at any point in the system of the invention, once a packet of data representing average traffic speed for a given direction of a given monitor road portion is known and available. The choice of where to perform this function is largely dependent upon considerations of signal complexity, and reliability of the nature of the transmission route [e.g. wired or wireless] that is being used. 
   In step  25 , The color-code-assigned data signals representing traffic speed conditions for each covered section and sub-section of a given section station  20 , are sorted and composed for transmission via transmitter unit  28  to all available vehicle stations  40  and to any optional central processing station(s)  30 . In this step  25 , the data received from all monitor stations are sorted by route identification, section identification and subsection identification (which also corresponds generally to the monitor identification). This enables the vehicle receiving station to recognize and process the received data in accordance with this invention, more efficiently. The operation of vehicle stations  40  and central stations  30  will be described in further detail elsewhere herein. 
   At the conclusion of step  27 , the algorithm of  FIG. 5  will proceed to step  27 , transmitting the processed data for reception by all vehicles, and then will return the operation of each section station  20  to step  21 , so that the cycle of operation of the algorithm of  FIG. 5  can begin again. Once again, it is noted that signal transmission to vehicle stations  40  of necessity must be wireless in nature, while transmissions from section stations  20  to a central station  30  may be in any desired and suitable form although it is assumed, in view of the distances likely to be involved, that wireless transmission will be preferable. 
   The operation of the system of this invention has been described, up to this point, in terms of the operation of the monitor stations  10  and the corresponding section station  20 . Now, it should be understood that the operation of the vehicle station  40  is an essential aspect of the invention. More specifically, the vehicle station  40 , as shown in  FIG. 3 , incorporates a display device unit  48  that provides the operator of the corresponding vehicle (not shown) with a valuable informational display in accordance with the invention. That is, display unit  48  may be an entirely conventional GPS navigational screen display device, set up to display route maps currently available for GPS navigation systems. However, it is a feature of this invention that the user/operator is provided with an on-board-vehicle map display in which each monitored route on the map is shown in colors representative of current, real-time traffic speed conditions on each route. Although GPS-related and other forms of on-board map displays are well known at this time, the inventor of this system believes that no other system provides information representative of real-time traffic speed conditions on a given route on an on-board map display. 
   When a vehicle station  40  is in use, vehicle receiver  42  receives from the nearest section station  20  and supplies to microprocessor  44 , signal packets containing section and sub-section identifying data provided by the section station and its associated monitor stations  10 . This information is fed to GPS interface unit  46  which identifies the global geographic position of the vehicle station so that the corresponding geographical area map will be selected from on board map data base unit  50 , with the support of vehicle station processor  44 , for display on the screen of display unit  48  in accordance with existing technology.  FIG. 9  shows in symbolic form, the information exchanged between interface unit  46  and display unit  48  to make it possible for the display unit to display route maps with color codes applied to the appropriate road portions. The “route disable” request and “route enable” request information shown in  FIG. 9  is explained subsequently herein with reference to FIG.  13  and FIG.  14 . In accordance with this invention, when the appropriate map is displayed on unit  48 , color-coded traffic information signals received from the controlling section station  20  are applied through interface unit  46  to display local routes in colors corresponding to traffic speed on each route portion, in accordance with this invention. 
   As described up to this point, this invention can be seen to provide a map display system in which each monitored route on a displayed map of the area surrounding the vehicle will appear in a highlighted color indicative of the real-time average speed of current traffic on that route. Now it can be explained, with reference to  FIG. 13 , that a further feature of this invention utilizes the color-code algorithm of  FIGS. 8A ,  8 B and FIG.  15 , to identify average traffic speed that is below a predetermined acceptable threshold value, and then “disables” that portion of a route while seeking an alternate. That is, when average traffic speed below the pre-determined threshold value is recognized on a particular road section, processor unit  44  in vehicle station  40  follows a pres-set procedure in accordance with the algorithm illustrated in  FIG. 13  to “disable” that route section. In this context, the term “disable” means that a signal is “attached” in any well-known manner to the identification data for that particular route section, so as to reset to a maximum number, say 9,999 hours, the normal “travel time” and/or distance assigned to that route portion within the GPS. The “normal travel time” data is readily available from the map database unit  50  associated with the GPS unit  48  in vehicle station  40 . The “reset” values for the time and/or distance are stored conveniently in the memory of associated processor  44 , together with the road section identification and the original “normal” values for that section, which are used later for “restoration” or “re-enablement” when appropriate, as explained elsewhere herein. When the indicated travel time for a road section becomes so large, that road section becomes “unacceptable” under standard GPS procedures, and existing GPS software automatically seeks an alternate route to be highlighted as the new “preferred” route on a displayed map. The color code assignment process of this invention continues in normal effect while a route portion is “disabled”, so that when traffic speed returns to normal or acceptable values, and the associated color code appears on that section of road on the displayed map, the “disable” setting for the affected road section may be eliminated using the algorithm illustrated in FIG.  14 . 
   In accordance with the algorithm of  FIG. 14 , when a step  151  “route enable” request has been initiated in any manner, the processor of the affected station, preferably vehicle station  40 , locates the identified “disabled” route portion in step  153  and proceeds to step  155  in which the original (i.e. “normal”) travel time and/or distance values for that road portion are restored to map database unit  50  as mentioned elsewhere herein. The route “enable request” may be initiated in any convenient manner, but preferably it will be initiated automatically in response to detection of return of the average speed data for that section to its “normal” value as established and available within the GPS. 
   With regard to reception of signals from section stations  20  by vehicle stations  40 , it will be understood that as a vehicle proceeds toward its destination, station  40  will necessarily progress away from one section station  20  while it approaches another. Accordingly, there will be times when the vehicle station  40  will be equidistant between two such section stations  20 , and the vehicle station may well be within range of the transmitted signals from two or more such stations. Under such circumstances, a conventional signal-strength discrimination circuit of known design incorporated into or otherwise associated with vehicle receiver  42  will assure, for example, that the receiver  42  continues to function under the control of whichever section station signal it is then receiving; such control will continue until the relative strength of the signals from the next section station exceeds the strength of the signals from the then-current section station by a predetermined value or ratio. At that point, the conventional discrimination circuit causes receiver  42  to recognize the stronger of the two signals and to cease responding to the former, now weaker, signals. 
     FIGS. 8A and 8B  together with  FIG. 15  illustrate the algorithms applied by section stations  20 , in accordance with the invention, to assign color coding to monitored route sections, to be displayed as described above. That is, in step  101 , for each monitor station  10  where the average traffic speed T is determined to be 55 miles per hour (MPH) or greater, the color assigned to the subsection of a route monitored by that monitor station is Green. The signal for “green” is associated with the corresponding route portion in accordance with established electronic display practice. If T is determined to be less than 55 MPH but greater than or equal to 45 MPH, step  101  proceeds to step  103  which then assigns the color Green/Yellow to the monitored subsection. Continuing in the same manner, if T is determined to be less than 45 MPH but greater than or equal to a predetermined minimum value, say 40 MPH, another color, Dandelion, is assigned to the display of the monitored subsection of a route. For the sake of completeness, it is noted that step  107  (shown in  FIG. 8B ) assigns the color Yellow to a monitored route portion where the traffic speed is determined to be in the range of less than 40 MPH and greater than or equal to, say, 30 MPH; for the speed range of less than 30 MPH and greater than or equal to 20 MPH the color Orange is assigned in step  108 , and finally, in step  109 , for speeds less than 20 MPH the color Red is assigned. It will be understood readily, that this color-assignment algorithm may be extended without difficulty to encompass any desired speed ranges higher and/or lower than those here described, and similarly may encompass speed ranges of any desired value, equal to or different from the 5 MPH and 10 MPH ranges here disclosed for illustrative purposes only. 
   When each traffic speed signal packet has been assigned a color code, that color is applied to the corresponding route map display data signal in accordance with the algorithm of FIG.  15 . In step  171  processor  44  of vehicle station  40  receives the current color code data signals and assigns the appropriate color code to the corresponding route data signal in step  173  so as to display the related portion of each route in the indicated color corresponding to the current average traffic speed on that route portion. In step  175 , the processor determines that each reported route portion has been processed and returns the processor to “waiting status” to begin the next cycle of color code application. 
   In the context of displaying traffic conditions for a particular route on a given map display, it should be noted that the system of this invention contemplates providing the operator of a vehicle with route status information on all monitored routes included within the scope of a displayed map. If desired, a particular destination may be selected (identified) manually using various forms of known electronic or electromechanical technology, including “keyed-in” entries on standard “keyboards” or dedicated and appropriately labeled, individual signal devices in vehicle stations  40 , such as push buttons  49 , shown associated with the GPS “on-board” display unit  48  in FIG.  11 . When a particular destination is selected as by sending a GPS signal identifying a given geographic location, existing GPS technology is used to identify a “preferred” route, between the geographic location of the vehicle station and the geographic location of the selected destination; the “preferred” route is then highlighted for visual identification on an electronic display screen, in any conventional manner. In a well-known manner, a dedicated signaling device may be associated readily with a given location by merely activating the signal device in a first condition while the vehicle station associated with the signal device is located at the desired location; thereafter, the signal device may be activated under a second condition to transmit a signal identifying the associated geographic destination. The first and second conditions referred to, may be achieved easily for example, by activating a dedicated “record” push button [one of pushbuttons  49 , for example] to achieve the first condition and allowing the “record” button to return to its at rest position to achieve the second condition. 
   With reference to receiver/display unit  48 , it is noted at this point that systems and apparatus for requesting wide area route map and other forms of display data, as well as display devices such as unit  48 , for receiving and rendering such data into informative visual displays, are well known in this art. Any suitable embodiments of such systems, apparatus and devices can be adapted readily for use in accordance with this feature of this invention, by one having ordinary skill in this art. 
   In normal operating mode, the system of this invention will color-code all of the monitored roads shown on the map displayed on unit  48 . In accordance with the objects of this invention, this will provide the operator of the vehicle with unique route and traffic condition information sufficient to make an informed choice of a personal route to follow to the destination of the operator&#39;s choice. Alternatively, when a particular destination has been selected, all of the monitored roads will continue to be displayed in color-coded form, but the preferred route to the selected destination will be both color-coded and highlighted to indicate its “preferred” status. In this form of route display an existing capability of the GPS system is utilized; this is the capacity to process input information identifying a specific geographic destination within a given geographic area and to respond by highlighting a preferred route between the then-current location of a then-current station and a selected geographic destination. 
   In accordance with the invention, destination identification information may be supplied to the traffic display system through remote download interface unit  45 , as mentioned previously herein. In one alternative as explained above, processor  44  may be coupled to one or more “dedicated” switches or push buttons  49  (shown in  FIG. 11 ) to provide processor  44  with data signals representative of specific, predetermined destinations; in such case, processor  44  may be programmed readily in conventional manner to permit the predetermined destination or destinations to be changed at will via interface with the GPS, for the convenience of a user of the system of this invention. In a still further and preferred alternative, a dedicated push button or other signaling or activation device may be made to correspond to a particular, frequently-used destination by activating the switch in one condition, e.g. a “setting mode” or “record” mode, when the vehicle station is located at the destination location. That is, for example only, identification data for a given destination may be stored, or “recorded,” for retrieval in response to activation of a specific, dedicated push button by entering a pre-determined code [to establish a first, condition, e.g. a “record” condition] and pressing the desired push button, when the vehicle is located at the desired destination. After the recording/storing operation is complete, the determined code may be canceled automatically to return the now-dedicated push button to a second condition in which it serves only to male the selected destination identification data code signal available to the traffic display system for further processing. 
   Once the mobile vehicle station has been made aware of a specific destination, a preferred route to that destination will be selected in accordance with the internal operations of the existing GPS navigation system, and in cooperation with the vehicle microprocessor  44 , color-coding display information will be applied to that selected route. Color coding will beapplied, as well, to all other routes on the displayed map in accordance with the invention. Accordingly, the system of this invention permits the vehicle operator to choose whether to: [a] follow the highlighted preferred route or [b] voluntarily follow any other route, or [c] follow an alternate “preferred” route identified by the system of the invention in accordance with the algorithm shown in  FIG. 6 , which is explained below. In accordance with choice [b], the vehicle operator may simply ignore the displayed route and choose to follow another route among the roads shown on the displayed map. 
   In accordance with choice [c], the system of the invention preferably may be set up to proceed automatically into the algorithm of  FIG. 6 , or may be set up so that the algorithm will be carried out only upon activation of a specific “activation” signal from, for example, a “dedicated” push-button  49  such as is shown in FIG.  11 . In brief, when the reported average traffic speed on any portion of a preferred route falls below a predetermined minimum value, that portion of the preferred route may be marked so as to “disable” that portion. In that case, the system of this invention may be programmed to automatically select an alternate preferred route in accordance with the algorithm illustrated in FIG.  6 . 
   The algorithm of  FIG. 6  is automatically initiated by routine scanning to detect, in step  121 , if any portion of any route has been assigned a color code that characterizes a “traffic jam”, say, for example, a speed, T, under 20 MPH; if no such condition is detected, the algorithm terminates its operation by proceeding to “done”, and resumes “waiting” status. In step  123 , following detection of a color code signal indicating a traffic jam condition, the system determines if the identified road section coincides with any part of a preferred or “selected” route; if the identified section does not coincide, operation of the algorithm terminates and returns to done or “waiting” status, as above. If, on the other hand, the detected “traffic jam” road section is found to be part of a selected route, the algorithm proceeds to step  125 , wherein the identification of that portion of a route is located in the GPS database unit  50  on-board the vehicle and is then marked by microprocessor  44  as “unavailable” or “disabled” in accordance with the algorithm of FIG.  13 . As shown in  FIG. 13 , when a route portion is marked as Not Available in a vehicle station  40 , in accordance with the algorithm of  FIG. 6 , a “disable request” is initiated within the vehicle station in step  131  of  FIG. 13 ; in response to the disable request, the processor in the vehicle station marks the location of the “blocked” route section in step  133 , and in step  135 , the travel time and/or indicated length of the blocked section are (is) reset to a maximum number, say 999999 while the identification data of that section are stored by the processor. Next, the disable logarithm returns to its “complete”, i.e. waiting condition. Subsequently, an alternate “preferred” route to the desired destination is “selected” for display using existing algorithms included in the GPS. 
   When a route section has been “disabled” in this manner, microprocessor  44  in vehicle station  40  (see  FIG. 3 ) continues to control application of the color-coding signals received from section station  20  to each of the monitored routes displayed on display unit  48  of vehicle station  40 , while GPS system controls continue to highlight the newly selected alternate preferred route. 
   The overall operation of a vehicle station  40 , shown in  FIG. 3 , is understood most readily with reference to the algorithm set forth in FIG.  7 . In  FIG. 7 , it is clear that a vehicle station  40  begins operation with step  141 , by receiving signals from a nearby section station  20 . In this regard, it should be noted that in a system with multiple section stations along various routes, there will come a time when a vehicle station in a moving vehicle will be located within range of say two different section stations. It is also entirely possible that the range of transmission of signals from two nearby stations are likely to overlap, at least at times. Under these conditions, the vehicle station processor  44  is set up to select for processing, the stronger of the two signals, in accordance with well-known standard protocols for signal strength selection. Referring again to  FIG. 7 , it can be seen that step  143  instructs processor  44  to analyze, in step  145 , the route identification signal for every monitored subsection of a route reported by the selected section station  20  so as to retrieve the appropriate map data and to locate the corresponding appropriate map for display. When step  145  is completed, processor  44  proceeds to step  147  in which the color codes applied by section station  20  are applied to the map for display on display unit  48  in the receiving vehicle station  40 . As mentioned previously herein, the generation and application of color code signals in step  147  can be carried out alternatively in other processors within the apparatus of the invention as, for example, in the processor of each of the monitor stations where the traffic information is first detected. Step  149  shown at the right side of  FIG. 6 , returns the algorithm cycle back to its beginning for another cycle, when the last subsection signal packet is received from the subject section station  20 . 
     FIG. 9  of the drawings illustrates, for convenience, the information exchanged via the GPS interface unit  46  across the interface between a vehicle station  40  and the GPS navigation display unit  48  associated with the vehicle station. As shown in this figure, vehicle station  40  provides to the navigation display  48  via the GPS interface unit  46  four different kinds of signals to control the visual display on unit  48 . These signals are, namely, [1] the color-coded route data received from a section station  20 ; [2] the “route disable” signal that identifies a particular section or sub-section of a route as unusable due to a “traffic jam” situation having been detected; that is, the calculated “average speed” for the monitored road is zero or substantially below a minimum value, say 5 or 10 miles per hour; and [3] a “route enable” signal generated by processor  44  and interface unit  46  together, in response to either a GPS route identification signal or a route request entered into the remote download interface unit  45 . With reference to interface unit  45 , it should be understood that the function of the interface is to receive and process input data in various forms from external sources such as the output of a laptop computer [not shown] and exchange that data with microprocessor unit  44 . 
   The underlying basic system of this invention has been disclosed in the specification set forth up to this point, with each element of the system having been described together with its function within the system. Now, summarizing the system and its operation as they have been described up to this point, and referring to the “system overview” of  FIG. 12 , it will be recognized that vehicle stations  40 , each including a receiver  42 , a processor  44 , and a GPS display unit  48  are carried in individual vehicles that participate in using the system. A plurality of section stations  20  are positioned at spaced-apart locations along vehicular roadways, and groups of monitor stations  10  are positioned at spaced-apart locations along the roadways, each group of monitor stations being located in the vicinity of, and being associated with, a particular section station. Each of the monitor stations  20  senses the speed of vehicular traffic in one or both directions in the vicinity of the monitor station and transmits corresponding information signals to an associated section station  20 ; in turn, each section station receives signals from its plurality of associated monitor stations  10 , processes the received signals preferably imparting color codes to specific, identified route signals in response to traffic conditions reported by the monitor stations for their corresponding sub-sections of a route, and transmits/broadcasts those “real-time” traffic data signals via data transmission unit  28 , for receipt by vehicle stations  40  in the area. Although it has been mentioned that color-coding of the traffic signals transmitted by each monitor station is preferably generated at the section stations, it will be understood that color-coding may, in accordance with this invention, be assigned if desired at other points along the signal transmission/processing path, such as at each monitor station or in each vehicle station. 
   Continuing this summary of the operation of the system of this invention: receiver unit  42  in each vehicle station  40  supplies the received traffic data signals to the vehicle processor  44  which then interacts with display unit  48  and with the received route section identification signals, via map database unit  50 , to display a map of the area surrounding the vehicle station  40 . Optionally, a user may choose to activate a control switch or device  49  to “request” that display unit  48  interact with the GPS system, using GPS interface unit  46 , to display wide area road maps other than those stored in map database unit  50  in vehicle station  40  to provide the user/vehicle-operator with a different or enhanced perspective of the surrounding area. Such maps may be stored at and made available from optional central station  30 , identified elsewhere in this specification. Communications between vehicle station  40  and the GPS system may use any suitable form of communications system available for this purpose. The choice between color coding all of the roads or only selected routes is made by the user of the system by choosing to provide processor  44  of vehicle station  40  with data identifying a particular destination for the vehicle station; if a particular destination is not identified or “given,” all of the roads shown on the displayed map on display unit  48  are color-coded. The color-codes are supplied together with the signals transmitted by the station selected to perform this function, as explained elsewhere in this specification, in accordance with the algorithm shown in  FIGS. 8A and 8B . 
   Although a preferred embodiment of the invention has been illustrated and described, those having skill in this art will recognize that various other forms and embodiments now may be visualized readily without departing significantly from the spirit and scope of the invention disclosed herein and set forth in the accompanying claims.