Car navigation system, traffic information providing apparatus, car navigation device, and traffic information providing method and program

In the present invention a traffic information providing apparatus makes a vehicle location and a running date a starting point, and predicts arrival time to each link included in a designated area, based on current traffic information provided by a traffic information center; meteorological forecast information provided by a meteorological information center; and statistical traffic information acquired from a traffic information data base where past traffic information is stored, thereby produces meteorological consideration traffic prediction information of the link, and sends the produced meteorological consideration traffic prediction information to a car navigation device. Then the car navigation device is configured to receive the produced meteorological consideration traffic prediction information and to search a guidance route, based on the produced meteorological consideration traffic prediction information.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a car navigation system, a traffic information providing apparatus, a car navigation device, and a traffic information providing method and program where predicted traffic information is applied, considering meteorological information.

2. Description of the Related Art

A car navigation device of recent years not only displays a shortest distance route to a destination and performs a route guidance according to the shortest distance, but also receives newest traffic information such as a traffic jam and a travel time provided by FM character multiplex broadcasting, for example, from VICS Center (Vehicle Information and Communication System Center), derives a shortest time route with considering the traffic information, and performs a route guidance according to the shortest time route.

However, because newest traffic information used at this time is present traffic information or traffic information a little earlier than present, a guidance route calculated by the car navigation device is not always a shortest time route. For example, in a case that a link A is not jammed at present where a vehicle is scheduled to pass after one hour, even if the link A is predicted to be jammed after the one hour, a guidance route passing such the link A is calculated if based on a calculation method of a current guidance route.

Consequently, for example, in Japanese Patent Laid-Open Publication No. 2003-151079 (paragraphs 0019 to 0052, FIGS. 1 to4, and 6 to 9) is disclosed a method of predicting time when a vehicle passes and calculating a guidance route, based on traffic information such as a jam at the predicted time and a travel time. According to the method, in a case that the link A scheduled to be passed after one hour is predicted to be jammed after the one hour, it is enabled to calculate such a guidance route that avoids the link A. Meanwhile, the prediction of the traffic information is assumed to consider such a season, a day of the week, and a meteorological phenomenon.

In accordance with the calculation method of the guidance route disclosed in the Japanese Patent Laid-Open Publication No. 2003-151079, although a meteorological condition is assumed to be considered in predicting traffic information, the meteorological condition indicates weather at that time, a static meteorological condition such as a fine weather, rain, and snow. However, a meteorological phenomenon, weather ever changes similarly to a traffic condition of a road, and drastically changes at some time. Then being accompanied with the weather change, the traffic condition also largely changes. Accordingly, if traffic information is predicted with a static meteorological condition at that time, especially in a case that weather suddenly changes, a reliability of the predicted traffic information results in being lowered.

In view of the problems of the conventional technology thus described are strongly requested a car navigation system, a traffic information providing apparatus, a car navigation device, and a traffic information providing method and program configured to predict traffic information, considering meteorological information, and to calculate a guidance route, based on the predicted traffic information.

SUMMARY OF THE INVENTION

In the present invention a traffic information providing apparatus makes a vehicle location and a running date a starting point, and predicts arrival time to each link included in a designated area, based on current traffic information provided by a traffic information center; meteorological forecast information provided by a meteorological information center; and statistical traffic information acquired from a traffic information data base where past traffic information is stored, thereby produces meteorological consideration traffic prediction information of the link, and sends the produced meteorological consideration traffic prediction information to a car navigation device. Then the car navigation device is configured to receive the produced meteorological consideration traffic prediction information and to search a guidance route, based on the produced meteorological consideration traffic prediction information.

In other words, in a case of the meteorological consideration traffic prediction information thus produced, link cost (such a travel time of a link) after one hour predicted from a present traffic state, statistical traffic information of past traffic information, and weather forecast information is set, for example, as traffic information of a link where a vehicle is predicted to pass after the one hour and which is predicted to be jammed after the one hour, according to such a fine weather, rain, and snow at that time. Accordingly, using such the meteorological consideration traffic prediction information and searching a guidance route, it is enabled to search the guidance route where changes of traffic information and meteorological forecast information are considered. In other words, the link predicted to be jammed after one hour with considering the meteorological forecast information results in not being included in the guidance route.

BEST MODE FOR CARRYING OUT THE INVENTION

Here will be described an embodiment of the present invention in detail, referring to drawings.

FIG. 1is a drawing showing a general configuration of a car navigation system where a traffic information providing apparatus and a car navigation device (hereinafter referred to as “car-navi device”) related to the embodiment of the present invention are applied. InFIG. 1a traffic information providing apparatus1related to the embodiment is connected to a traffic information center2for distributing current traffic information and a meteorological information center3for distributing meteorological forecast information via a communication network4such as the Internet; and to a car-navi device6mounted on a vehicle10by a radio communication means via a base station5such as the communication network4and a mobile.

The traffic information providing apparatus1is configured with a so called computer (information processing unit) comprising a CPU (Central Processing Unit), a memory unit, and a hard disk unit not shown. Then the traffic information providing apparatus1comprises, as shown inFIG. 1, functional blocks such as a communication interface unit11, a traffic information acquisition unit12, a meteorological information acquisition unit13, a traffic information DB (Data Base)14, a traffic information prediction unit15, a traffic prediction information request reception unit16, and a traffic prediction information providing unit17. Meanwhile, such the functional blocks are realized by the CPU running programs memorized in a semiconductor memory and a hard disk unit.

InFIG. 1the traffic information acquisition unit12acquires current actual traffic information from the traffic information center2via the communication interface unit11and memorizes it in such a memory unit. In addition, the meteorological information acquisition unit13acquires meteorological forecast information from the meteorological information center3via the communication interface unit11and memorizes it in such a memory unit. In addition, the traffic information DB14is a data base where statistical traffic information is stored, wherein actual data of past traffic information is statistically processed.

Meanwhile, although the traffic information DB14is here configured to be included in the traffic information providing apparatus1, it may also be included in the traffic information center2, and in addition, included in an independent data base server connected to the device1via the communication network4.

The traffic prediction information request reception unit16receives information (hereinafter referred to as “traffic prediction information request”) for requesting traffic prediction information sent from the car-navi device6, and activates the traffic information prediction unit15. At this time the traffic prediction information request includes information such as a vehicle location of a prediction starting point, a running date and hour, and a designated area of a prediction object.

The traffic information prediction unit15is activated by the traffic prediction information request reception unit16; predicts traffic information based on current traffic information and meteorological forecast information respectively acquired by the traffic information acquisition unit12and the meteorological information acquisition unit13, and further based on statistical information of past traffic information read from the traffic information DB14; and produces meteorological consideration traffic prediction information. Then the traffic prediction information providing unit17provides the meteorological consideration traffic prediction information produced by the traffic information prediction unit15to the car-navi device6.

Meanwhile, all information included in the traffic information DB14is not necessarily needed to be the statistical information of past traffic information, its part or all may also be information acquired by such a test car; particularly, with respect to such a newly opened road, traffic information acquired by such a simulation is also available. In addition, in the traffic information DB14may also be included such information as a presence or absence of a traffic regulation, construction, an accident, a hazard; vacant/full information of a parking lot and an establishment; and a condition (open/close) of a toll booth and a service area.

In the car-navi device6, as shown inFIG. 1, to a main body unit61are connected such a display unit62, a mobile phone63, and a GPS (Global Positioning System) receiver64. Here, the main body unit61is configured with a small computer comprising such a memory unit and a hard disk unit. Meanwhile, instead of the hard disk unit or in addition to it, a DVD (Digital Versatile Disk) and a portable memory card may also be used. The main body unit61communicates with the base station5of the mobile phone63by it and is connected to the traffic information providing apparatus1via the communication network4.

The car-navi device6sends a traffic prediction information request to the traffic information providing apparatus1and thereby can receive provision of meteorological consideration prediction traffic information from the device1. Then the car-navi device6calculates a guidance route to a destination input by a driver of the vehicle10, based on such the meteorological consideration prediction traffic information, and outputs guidance route instruction information according to the guidance route to the display unit62. Meanwhile, the guidance route instruction information may also be output as a voice, using such a speaker.

<Function of Traffic Information Providing apparatus>

Next will be in detail described a traffic information prediction of a main function of the traffic information providing apparatus1and a configuration of information used relating to the prediction, usingFIGS. 2 to 9.

The traffic information DB14stores statistical traffic information, where past actual data is statistically processed with respect to traffic information of each link, as base data for predicting traffic information.FIG. 2is a drawing showing an example of statistical traffic information of a link stored in the traffic information DB14. In other words, as shown inFIG. 2, in the traffic information DB14, traffic information such as a travel time and jam length of the link divided, for example, into cases of a fine weather, rain, and snow is statistically processed for every five-minute interval and stored.

Meanwhile, although in the example ofFIG. 2a time interval for performing statistical processing assumed to be five minutes, it may not be five minutes and be changed as needed. In addition to the cases of a fine weather, rain, and snow, values such as a rainfall amount, a snowfall amount, a temperature, a wind speed may be combined as a statistical unit of weather. Furthermore, statistical data divided into a day kind such as a day of the week, Saturday, a holiday, a season, and an event day is also available. In addition, in collecting traffic information may also be used a travel time and speed information by which own vehicle ran, other than information supplied from the traffic information center2.

FIG. 3is a drawing illustrating a prediction method of a travel time, based on actual data of present traffic information and past statistical data. InFIG. 3a polygonal line30represents statistical data of the travel time stored in the traffic information DB14; a polygonal line31, actual data of the travel time to a present time t of a prediction current day supplied from the traffic information center2; and a polygonal line32(dotted line), prediction data of the travel time after the present time t. In other words, it is shown that the travel time is Td′(t) at the present time t and becomes Td′(t+1) at time (t+1) after an elapse of a unit time.

At this time, assuming that a ratio of the travel time Td′(t+1) to a travel time Td(t+1) of the statistical data at the time (t+1) is nearly equal to that of the travel time Td′(t) to a travel time Td(t) of the statistical data at the present time (t), the travel time Td′(t+1) at the time (t +1) can be predicted according to an equation (1):
Td′(t+1)=Td(t+1)×γ×Td′(t)/Td(t),  Eq. (1)
where γ is a coefficient and normally assumed to be γ=1.

However, in a case that the ratio Td′(t)/Td(t) of the current travel time Td′(t) to the travel time Td(t) of the statistical data at the present time (t) is extraordinary larger or smaller than a normal value, the γ may also be made to be less than 1 or more than 1 as needed.

In addition, assuming that a difference (time variation amount) between the travel time Td′(t+1) and the travel time Td(t+1) of the statistical data at the time (t+1) is nearly equal to that of the travel time Td′(t) and the travel time Td(t) of the statistical data at the time (t), the travel time Td′(t+1) at the time (t+1) can be predicted according to an equation (2):
Td′(t+1)=Td(t+1)×δ×(Td′(t)−Td(t),  Eq. (2)
where δ is a coefficient and normally assumed to be δ=1.

However, in a case that the difference between the current travel time Td′(t) and the travel time Td(t) of the statistical data at the time (t+1) is extraordinary large, the δ may also be made to be less than 1 as needed.

Thus although in the example a method of predicting a travel time at the time (t+1) is described, if further predicting following travel times for every unit time based on the predicted travel time, it is enabled to predict travel times at time (t+2), (t+3), . . . (t+n). Meanwhile, the unit time means a time interval when past actual data is statistically processed, and for example, inFIG. 2, is five minutes.

In addition, in the prediction of travel times by the equations (1) and (2) thus described, the values of Td(t), Td(t+1), . . . Td(t+n) are derived, referring to the traffic information DB14shown inFIG. 2. At this time meteorological information used in referring to the traffic information DB14is each information at each time (t), (t+1), . . . (t+n) in meteorological forecast information acquired from the meteorological information center3. Accordingly, the values of the travel times Td(t), Td(t+1), . . . Td(t+n) correspond to changes of meteorological forecast and become the values corresponding to the meteorological phenomena. Accordingly, in the embodiment it is enabled to predict traffic information, considering meteorological forecast information.

Next will be more concretely described a method of predicting traffic information, usingFIGS. 4 to 8. Here,FIG. 4is a drawing showing an example of a road network illustrating a usage method of a predicted travel time. InFIG. 4symbols A to E represent intersections; symbols40to43represent road links. In addition,FIG. 5is a drawing showing an example of a predicted travel time at each predicted time of the links40to43.FIG. 6is a drawing showing an example of a predicted travel speed at each predicted time of the links40to43. InFIGS. 5 and 6, a predicted travel time where a meteorological condition is considered is made for every fine weather, rain, and snow at each predicted time. Meanwhile, the predicted travel speed ofFIG. 6can be derived from the predicted travel time and a link length.

FIG. 7is a drawing showing an example of calculating a predicted travel time in traveling intersections A to E, using the predicted travel time and the predicted travel speed shown inFIGS. 5 and 6. Assume that a prediction current day is a fine day: in a case of departing the intersection A at time 10:00:00, it is predicted that it takes 72 seconds (average speed, 30 km/h) to pass the link40; because arrival time 10:01:12 does not reach 10:05, use 25 km/h as a travel speed at the next link41; therefore, a predicted travel time required for passing the link41is 144 seconds, and a sum-up travel time from the intersection A becomes 216 seconds.

Similarly, because a travel time required for passing the link43is 173 seconds (sum-up 471 seconds), it is requested to change to a speed of 10:05 on the way. In other words, because the speed (25 km/h) of 10:00 is used for first two seconds after proceeding into the link43, a running distance during that time is about 14 m; with respect to remaining distance 1186 m, because the speed (15 km/h) of 10:05 is used, it is predicted that it takes about 285 seconds. After all, it is predicted that a travel time required for passing the link43is 287 seconds (sum-up 585 seconds).

Accordingly, predicted time of a vehicle arriving at the intersection E after departing the intersection A at 10:00:00 is 10:09:45. Its running state can be expressed as a graph of a polygonal line71inFIG. 7. Similarly, a running state in a case of a predicted current day being rainy can be expressed as a graph of a polygonal line72inFIG. 7, a predicted trip time to the intersection E is 806 seconds, and predicted time is 10:13:26.

FIG. 8is a drawing showing an example of a configuration of meteorological forecast information acquired from a meteorological forecast center. As shown inFIG. 8, the meteorological forecast information is designed to be a format where weather information is memorized for every area and every predicted date and hour like “weather of an area 1; cloudy from 00:00 to 6:00, and fine from 6:00 to 12:00, Jan. 30, 200X.”

Here, the “area” is a region of a unit where meteorological forecast information is provided, and means a region divided by a governmental block such as prefectures, a city, a ward, a town, and a village, or a region of a mesh unit divided by a longitude and a latitude. However, for a purpose of providing traffic information to the car-navi device6, it is more convenient to handle the area as a mesh unit; therefore in a case of meteorological information being provided according to every governmental block is performed conversion processing of the meteorological information of the governmental block to that of the mesh unit. As a simple conversion method, it is enabled to make meteorological information of a mesh corresponding to that of a governmental block from a location relationship between the governmental block and the mesh area. Or else, from a location relationship between a place of a meteorological observatory and a mesh area, meteorological information of a region where the observatory is located may also be made that of the mesh where the observatory is located.

Meanwhile, in the example ofFIG. 8, although meteorological information is provided at every time zone where a day is divided with six hours, the interval of the time zone may be changed as needed. In addition, by using a shorter time meteorological forecast (time sequential forecast) with respect to a vicinity of own vehicle, and a shorter period meteorological forecast (the day after tomorrow forecast) with respect to an area distant from own vehicle not less than a predetermined distance, it is enabled to heighten a hitting ratio of traffic prediction information of a running scheduled place (vicinity of own vehicle) in the near future. Furthermore, a present meteorological phenomenon may also be used in the vicinity of own vehicle; a meteorological forecast may also be used in an area distant from own vehicle not less than a predetermined distance. Thus by changing an update frequency of traffic prediction information according to a distance from own vehicle, it is also enabled to increase the update frequency of the vicinity of the own vehicle and to heighten a hitting ratio of a prediction. In addition, the forecast information may also include not only the information of a fine weather, rain, and snow but also that including a rainfall amount and a temperature.

In addition, as a method of predicting traffic information, although there are various methods such as a method of taking traffic flow on a road as is a fluid and estimating a jam interval, other than the method of using statistical information thus described, it is enabled to predict the traffic information according to meteorological information in any method similarly to the description of the embodiment by providing an estimation parameter according the meteorological information.

FIG. 9is a drawing showing an example of a configuration of traffic prediction information provided to a car navigation device by a traffic information providing apparatus. The traffic prediction information comprises predicted time for every area and forecasted meteorological information (weather and the like) at the predicted time of the area, and further comprises information such as a predicted travel time, a jam length, and a travel speed with respect to each link included in the area. Furthermore, as detailed traffic information, such a jam occurrence place within the link may also be included.

FIG. 10is a drawing showing a functional block diagram of a car-navi device (main body unit). As shown inFIG. 10, the main body unit61of the car-navi device6comprises functional blocks such as a communication interface unit601, a traffic prediction information acquisition unit602, an input instruction unit603, a traffic prediction information DB604, a statistical traffic information DB605, a guidance route search unit606, a plurality-of-comparison-routes search unit607, a meteorological-comparison-route search unit608, a vicinity establishment search unit609, and a display interface unit610.

InFIG. 10, based on information from the input instruction unit603for receiving an input by a driver of the vehicle10, the traffic prediction information acquisition unit602sends a traffic prediction information request to the traffic information providing apparatus1via such the communication interface unit601and the mobile63, attaching information such as a destination, a predicted area, and a date and hour. Then receiving traffic prediction information sent from the traffic information providing apparatus1, the traffic prediction information acquisition unit602stores the received traffic prediction information in the traffic prediction information DB604. Meanwhile, a configuration of the received traffic prediction information at this time is as shown inFIG. 9.

The statistical traffic information DB605is a data base where traffic information made by statistically processing past traffic information is stored, and the information is memorized in advance in manufacturing or selling the car-navi device6. In addition, when necessary, the statistical traffic information DB605can acquire necessary statistical traffic information from the traffic information providing apparatus1via the traffic prediction information acquisition unit602, and store the statistical information. However, although because statistical traffic information is not information changing day by day, it is unnecessary to acquire the statistical information from the traffic information providing apparatus1in each case, the statistical information may also be periodically updated at such any change timing of a year, a month, and a season.

Meanwhile, there is some case that the statistical traffic information of a new area is requested, depending on a set destination, and then the traffic prediction information acquisition unit602sends information requested by the statistical information to the traffic information providing apparatus1with attaching information such as an area, and acquires the statistical information of a necessary area.

InFIG. 10each functional block of the guidance route search unit606, the plurality-of-comparison-routes search unit607, the meteorological-comparison-route search unit608, and the vicinity establishment search unit609is for realizing various route search functions of the car-navi device6, and its detail will be described, using drawings afterFIG. 11. Meanwhile, the functional block is realized by a not shown CPU included in the main body unit61for running a program stored in a semiconductor memory not shown.

<<Route Search and Display by Traffic Prediction Information Including Meteorological Forecast Information>>

FIG. 11is a flowchart of navigation processing of using traffic prediction information in the car-navi device6. InFIG. 11, if such a driver of the vehicle10sets such a condition of a destination and a route search by an input means such as a key button, the traffic prediction information acquisition unit602requests traffic prediction information for the traffic information providing apparatus1, attaching information such as a predicted area, and a date and hour; acquires the traffic prediction information of the predicted area and the date and hour requested (step S11); and stores the acquired traffic prediction information in the traffic prediction information DB604. Next, the guidance route search unit606sets link cost of a road (step S12), based on the traffic prediction information stored in the traffic prediction information DB604, and searches a guidance route (a normal recommended route is a shortest time route) from a present location or a point set by the driver to a destination (step S13).

Subsequently, the guidance route search unit606determines whether or not meteorological forecast information is included in the traffic prediction information used in the route search (step S14); if the meteorological forecast information is included (Yes in the step S14), the unit606calculates predicted arrival time at predetermined points (such a present point, a via-point, the destination, and a point designated by the driver in advance) on the searched guidance route, and acquires meteorological forecast information at the predicted arrival time (step S16). Then the guidance route search unit606displays the guidance route, for example, as shown inFIG. 12, in the display unit62via the display interface unit610, and further displays the predicted arrival time at the predetermined points and the meteorological forecast information thereat (step S17). After then, if the vehicle10runs according to the searched guidance route, the guidance route search unit606outputs guidance instruction information every time when the vehicle10passes such an intersection (step S18).

In addition, if the meteorological forecast information is not included in the step S14(No in the step S14), the guidance route search unit606merely displays the guidance route via the display interface unit610(step S15), and after then, outputs guidance instruction information according to the searched guidance route every time when the vehicle10passes such an intersection (step S18). In other words, in this case is not displayed the meteorological forecast information in such the via-point during the guidance route. Meanwhile, even if the meteorological forecast information is not displayed, if the traffic prediction information acquired in the step S11is the information where the meteorological forecast information is considered, the guidance route displayed in the step S15is adapted to be the traffic prediction information where the meteorological forecast information is considered.

FIG. 12is a drawing showing an example of a display screen where a guidance route search unit displays a guidance route, predicted arrival time of its via-points, and meteorological forecast information thereat. A guidance route120is a recommended route from a departure point121to a destination122calculated on the basis of traffic prediction information. In addition, a symbol124is departure time, symbols125and126are scheduled pass time of the via-points, and a symbol127is predicted arrival time at a destination. If the guidance route120is traffic prediction information including meteorological forecast information, in addition to the predicted arrival time, the forecast information thereat is displayed in each display unit of the symbols126and127. In addition, considering safety during driving, the scheduled pass time of each via-point and the meteorological forecast information thereat may also be output, using a voice output means together with the display or instead of it. Meanwhile, inFIG. 12provision time information123indicates time when the traffic prediction information is provided.

FIG. 13is a drawing showing an example of a display screen where a guidance route search unit simply displays a guidance route, predicted arrival time of its via-points, and meteorological forecast information thereat. InFIG. 13, with respect to main via-points131to133from own vehicle point130to a destination quarter134, with icons are displayed names of the points, trip times calculated on the basis of traffic prediction information thereto, and the meteorological forecast information at the predicted arrival time.

<<Search of Plurality of Routes and Comparison Display thereof>>

The car-navi device6in the embodiment displays the guidance routes thus described, and comprises not only a function of outputting instruction information of a vehicle guidance but also that of calculating and displaying various pieces of route information. Here will be described various route searches and display functions thereof.

FIG. 14is a drawing showing an example of a condition setting screen when a route search is performed with a plurality of conditions in the car-navi device6. In the example of the condition setting screen, by selecting buttons of route search conditions141,142, and143, maximum three search conditions can be set. In addition, according to check boxes, the search conditions can be selected from such a toll road priority, an open road priority, a distance priority, a jam prediction consideration, a ferry priority, VICS usage, an automatic re-search, and a meteorological consideration. Here, the toll road priority, the distance priority, the jam prediction consideration, and the meteorological consideration are selected. Meanwhile, the check box of the meteorological consideration may also be made effective only when the jam prediction consideration is selected; or if the meteorological consideration is selected, the jam prediction consideration may also be assumed to be automatically selected.

FIG. 15is a drawing showing an example of a display screen when a route search is performed with a plurality of conditions in a car navigation device. InFIG. 15routes151to153are recommended routes from a departure point S to a destination G calculated according to different search conditions. In addition, symbols154to156are comparison summary information of the routes, and as the information are respectively displayed such search conditions, distances, trip times, and fees. Meanwhile, in a case ofFIG. 15a first route (solid line route151) is a route, where the toll road priority and the meteorological forecast information are considered, and indicates a result of predicting traffic prediction information in rain because the forecast information on a running day is rainy. In addition, a second route (chain line route152) is a route of the toll road priority, and a third route (broken line route153) is a route of the distance priority. Meanwhile, a running day may also be a running scheduled day separately designated with an input means by a driver.

Thus the car-navi device6performs the function shown inFIG. 15as processing of the plurality-of-comparison-routes search unit607(seeFIG. 10).FIG. 16is a flowchart of processing performed by a plurality-of-comparison-routes search unit.

InFIG. 16the plurality-of-comparison-routes search unit607firstly determines by the screen shown inFIG. 14whether or not any one of the jam prediction consideration and the meteorological consideration is set (step S21). Then if any one of the jam prediction consideration and the meteorological consideration is set (Yes in the step S21), the plurality-of-comparison-routes search unit607acquires traffic prediction information from the traffic information providing apparatus1via the traffic prediction information acquisition unit602(step S22), and stores the acquired traffic prediction information in the traffic prediction information DB604. In addition, if any one of the jam prediction consideration and the meteorological consideration is not set (No in the step S21), the plurality-of-comparison-routes search unit607skips to perform the step S22because it can use the statistical traffic information DB605in a guidance route search.

Next, with respect to a plurality of search conditions respectively set in the screen ofFIG. 14, the plurality-of-comparison-routes search unit607searches a plurality of routes to the destination G (step S23). Then, while changing display attributes (a kind of line, a display color, an icon, and the like) for every route via the display interface unit610(step S24), the plurality-of-comparison-routes search unit607displays the plurality of the searched routes (step S25). Furthermore, with respect to the plurality of the routes, the plurality-of-comparison-routes search unit607displays the comparison summary information (the symbols154to156inFIG. 15) of the routes (step S26).

<<Route Search for Plurality of Meteorological Conditions and Comparison Display thereof>>

FIG. 17is a drawing showing an example of a display screen when a route search is performed for a plurality of meteorological conditions. InFIG. 17a route171(displayed in solid line) indicates a recommended route in a case of meteorological forecast information being assumed to be fine; a route172(displayed in chain double-dashed line) indicates a recommended route in a case of the meteorological forecast information being assumed to be rainy. By acquiring a plurality of pieces of traffic prediction information for every meteorological condition of meteorological forecast information, it is enabled to comparatively refer to a recommended route for the meteorological condition. Meanwhile, a symbol173is summary information of the routes, and here, meteorological conditions and trip times to a destination are displayed, respectively. In addition, as the summary information, additionally such predicted arrival time and a distance to the destination may also be displayed.

FIG. 18is a flowchart of processing performed by a meteorological-comparison-route search unit, which displays the display screen ofFIG. 17. InFIG. 17the meteorological-comparison-route search unit608acquires traffic prediction information including a plurality of meteorological conditions from the traffic information providing apparatus1(step S31). Then the meteorological-comparison-route search unit608picks up one of the plurality of the meteorological conditions, and sets the meteorological condition of a route search (step S32). Then the meteorological-comparison-route search unit608sets link cost according to the traffic prediction information of the set meteorological condition, and searches the route (step S34).

Next, the meteorological-comparison-route search unit608determines whether or not the route search is performed with respect to all of the meteorological conditions (step S35), and if there exists any meteorological condition according to which the route search is not performed (No in the step S35), the unit608returns to the step S32and repeats the processing after the step S32. In addition, if the route search is performed with respect to all of the meteorological conditions (Yes in the step S35), while changing display attributes (a kind of line, a display color, an icon, and the like) via the display interface unit610(step S36), the meteorological-comparison-route search unit608displays the plurality of the searched routes (step S37). Furthermore, with respect to the plurality of the searched routes, the meteorological-comparison-route search unit608displays the comparison summary information173thereof (seeFIG. 17).

Meanwhile, in the processing thus shown inFIG. 18the meteorological-comparison-route search unit608may not also acquire the traffic prediction information (no requirement of the step S31), and may search routes, using the statistical traffic information stored in the statistical traffic information DB605. In this case, in the step S33the meteorological-comparison-route search unit608sets link cost according to the statistical traffic information of the statistical traffic information DB605instead of the traffic prediction information.

<<Search of Vicinity Establishment with Considering Meteorological Condition>>

FIG. 19is a drawing showing an example of a display screen when vicinity establishments are searched, considering a meteorological condition. InFIG. 19a list191is an example of a list display when a vicinity establishment is searched by designating an establishment category as a “Chinese noodle shop” at an own vehicle location130. In addition, it is indicated that a display of a symbol192is a vicinity list under a condition by which the vicinity establishment is searched, that is, the vicinity list where in the example a jam prediction and a meteorological condition are considered. At this time establishment names are sorted and displayed in ascending order of trip times to the establishments. In addition, the displayed list can be scrolled by scroll buttons193and194.

FIG. 20is a flowchart of processing of a vicinity establishment search, where a meteorological condition is considered and which is performed by a vicinity establishment search unit. InFIG. 20the vicinity establishment search unit609firstly acquires traffic prediction information including meteorological forecast information from the traffic information providing apparatus1via the traffic prediction information acquisition unit602(step S41). Next, the vicinity establishment search unit609sets such a category of an establishment to be searched in vicinity establishments, selects one of the vicinity establishments, and set it as a destination (step S42). Then the vicinity establishment search unit609sets link cost, based on the traffic prediction information (step S43), and searches a route to the vicinity establishment (step S44).

Next, the vicinity establishment search unit609determines whether or not routes to all of the vicinity establishments are searched (step S45), and if there exists any vicinity establishment not searched (No in the step S45), the unit609repeats the steps S42to S44. In addition, if the routes to all of the vicinity establishments are searched (Yes in the step S45), the vicinity establishment search unit609sorts the vicinity establishments in ascending order of trip times thereto (step S46), and displays the sorted vicinity establishments in a list (step S47).

Meanwhile, in the example shown inFIG. 20, although the trip times to the establishments displayed in the list are calculated according to traffic prediction information including meteorological forecast information in route search, they may also be calculated according to a route search using traffic information based on a meteorological condition input and designated with such a key button by a driver of the vehicle10. In addition, not acquiring the traffic prediction information but using statistical traffic information stored in the statistical traffic information DB605instead of the former, the route search may also be performed.

Thus in accordance with the embodiment, the car-navi device6can search a guidance route, based on traffic information provided from the traffic information providing apparatus1, wherein meteorological forecast information is considered. Therefore, the car-navi device6can calculate a highly accurate guidance route and a trip time to a destination even if meteorological information suddenly changes. Furthermore, the car-navi device6can perform a route search under meteorological forecast information and a meteorological condition with respect to not only the guidance route to the destination but also various route searches such as a search of a vicinity establishment, and improve a convenience for a user of the car-navi device6.

In the embodiment thus described the traffic information providing apparatus1connected to the communication network4uses statistical data of past traffic information stored in the traffic information DB14, actual data of present traffic information acquired from the traffic information center2, and meteorological forecast information acquired from the meteorological information center3; produces traffic prediction information including the meteorological forecast information; sends the produced traffic prediction information to the car-navi device6via the network4; and the device6performs a route search, using the traffic prediction information. Consequently, as a variation example of the embodiment, without providing the traffic information providing apparatus1, the car-navi device6may also be configured to perform all processing performed by the device1.

In this case the functional blocks12to17(the communication interface unit11is unnecessary because of its duplication) configuring the traffic information providing apparatus1is configured to be included in the main body unit61(seeFIG. 10) of the car-navi device6. Accordingly, the car-navi device6directly acquires actual data of present traffic information from the traffic information center2and meteorological forecast information from the meteorological information center3, and produces traffic prediction information including the meteorological forecast information within itself. Then the car-navi device6performs a route search, using the traffic prediction information produced by itself.

Accordingly, in the variation example of the embodiment, because the processing of the traffic prediction information request reception unit16, the traffic prediction information providing unit17, and the traffic prediction information acquisition unit602becomes information transfer processing performed within the car-navi device6, a communication load in the communication network4can be widely reduced.

Furthermore, contrary to the variation example of the embodiment is available a configuration that the traffic information providing apparatus1includes the function of the car-navi device6. In this case, as something corresponding to an input means of the car-navi device6and the display unit62can be appropriated a common personal computer, a PDA (Personal Digital Assistant), and a mobile connected via the communication network4. In other words, the traffic information providing apparatus1can receive a request of a route search from such the common personal computer, the PDA, and the mobile, and provide them with various pieces of traffic information such as a route where meteorological forecast information is considered.