JP2009163584A - Traffic information system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a traffic information system, capable of delivering, in the event of an emergent event such as traffic accident or road repairing, information for the range and degree of its influence on circumferential roads to an on-vehicle terminal device. <P>SOLUTION: Upon receipt of emergent event occurrence information, traveling histories of passing through the emergent event point are extracted from the past traveling histories of probe cars. Based on the extracted traveling histories, traveling frequencies of road links on which each probe car traveled are determined with respect to all the extracted traveling histories, and passing frequency information is created by normalizing the traveling frequency of each road link with the total number of probe cars which passed through the road link with the emergent event, and delivered to the on-vehicle terminal device. The on-vehicle terminal device displays the degree of influence in each road link based on the passing frequency information. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a traffic information system that can be used in an ITS (Intelligent Transport System) that provides traffic information such as road traffic congestion information to drivers and the like.

  Conventional traffic information systems, such as VICS (Vehicle Information & Communication System) (registered trademark), collect traffic information such as traffic jams via infrared sensors and optical beacons provided on the roadside, and FM multiplexing There are known services provided to in-vehicle devices (for example, car navigation systems, car televisions, character multiplex broadcast receivers) via facilities such as broadcasting and roadside beacons and radio beacons.

  Furthermore, in recent years, a probe traffic information service that collects traffic information using the vehicle itself as a sensor and provides it to an in-vehicle device has attracted attention. In this system, a vehicle collects history data (probe information) such as traveled position information and time information, and uplinks it to a traffic information center via a communication device such as a mobile phone or radio. Such a vehicle is called a probe car. In the traffic information center, probe information collected from each vehicle is converted into link traffic information and provided to each in-vehicle device via a communication device.

  The above-mentioned prior art provides raw information on traffic jams (for example, information on traffic jams, how many kilometers of traffic jams, etc.) and traffic jam prediction information based on past data. Further, the probe traffic information has a spatial loss because the travel position and timing of the probe car are random. In applications such as displaying information on an in-vehicle device or route search, if there is a defect in traffic information, appropriate processing cannot be performed, so it is necessary to supplement the missing data spatially. The probe traffic information service provides traffic information including supplemented traffic information.

  However, when considering actual road traffic, there are a number of traffic accidents such as small accidents and construction that cannot clearly express the road conditions. As such, it was not well communicated to the driver. Furthermore, when an event occurs, it is required to avoid the sudden event.

  On the other hand, Patent Document 1 discloses a method in which an in-vehicle device sets a virtual destination ahead of an accident occurrence point and searches for a detour route when an accident occurs. In this method, the virtual destination is set in the way of the traveling method of the car.

  Patent Document 2 also describes a method for predicting the recovery time of an accident from past accident data similar to the accident that occurred, and the future due to the accident by referring to the predicted recovery time and past traffic data. A method for predicting the length of traffic jam is disclosed. In this method, similar accident information is extracted from past accident data by using information on the number of accident vehicles, vehicle types, and the number of casualties.

  Patent Document 3 discloses a method of avoiding an accident occurrence point by selecting what the user thinks is appropriate from the detour distances of a plurality of detours presented by the in-vehicle device when an accident occurs. Examples of the detour distance here include 1 km, 2 km, and 5 km.

Japanese Patent Laid-Open No. 11-344349 JP-A-8-109209 Japanese Patent Application No. 2004-210854

  The in-vehicle device in Patent Document 1 searches for a detour route of a road link where a sudden event has occurred. However, since the range of influence on the road around the point where the sudden event occurred is not considered, it is not known whether the detour route presented by the in-vehicle device is appropriate.

  In the technique described in Patent Document 2, similar past accident information at a point different from the accident occurrence point is applied when searching for a detour route. Because the accident location has its own road structure and accident situation, even if accident information at a different point from the actual accident location is used, the traffic situation on the road around the accident occurrence point is also similar. It is not limited whether or not an appropriate detour route is required.

  Also in the surroundings of the technique described in Patent Document 3, as in Patent Document 1, a detour route of a road link where a sudden event has occurred is searched. However, since the range of influence on the road around the point where the sudden event occurred is not considered, it is not known whether the detour route presented by the in-vehicle device is appropriate.

  An object of the present invention is to provide a traffic information system capable of distributing information on the extent of impact and the extent of sudden events on roads around the sudden event occurrence point to on-vehicle devices when a sudden event such as a traffic accident or construction occurs. It is to be.

  In the traffic information center, the travel history information and the sudden event occurrence information transmitted by the probe car are received, and the travel history information passing through the road link where the sudden event has occurred is stored from the travel history information of the probe car that has been accumulated. To extract.

  For all road links included in the extracted travel history information, obtain the travel frequency of each probe car traveled, and calculate the travel frequency for each road link as the total number of probe cars that passed through the road link where the sudden event occurred. Generate pass frequency information normalized by. The passing frequency information is distributed to the in-vehicle terminal device as the degree of influence representing the influence of each road link due to the sudden event, and the passing frequency information is displayed in the in-vehicle terminal device.

  According to the present invention, immediately after the occurrence of an accident, it is possible to present information on the passing frequency from the surrounding road to the sudden event occurrence point, and the user or the in-vehicle device can consider the influence range of the sudden event.

  An embodiment of a traffic information system using the present invention will be described with reference to the drawings. In this traffic information system, it is assumed that the travel history collected from the probe car is sufficiently accumulated in advance.

  FIG. 1 is an overall configuration diagram of a traffic information system according to the present invention. As shown in FIG. 1, the traffic information system includes a center device 1 and a plurality of in-vehicle terminal devices 100.

  The center device 1 includes a probe data receiving unit 10, a map data storage unit 14, a probe data processing unit 15, a probe car travel history storage unit 20, a sudden event occurrence information reception unit 30, a sudden event information storage unit 35, and a travel history search unit. 40, the sudden event point passage frequency calculation unit 50, the passage frequency information generation unit 60, and the passage frequency information transmission unit 70.

  Each processing unit of the center apparatus 1 is broadly divided into a portion that performs offline processing and online processing. The parts corresponding to the offline processing are the probe data receiving unit 10, the map data storage unit 14, the probe data processing unit 15, and the probe car travel history storage unit 20. Further, the part corresponding to the online processing includes the sudden event occurrence information receiving unit 30, the sudden event information storage unit 35, the travel history search unit 40, the sudden event point passage frequency calculation unit 50, the passage frequency information generation unit 60, and the passage frequency information transmission. Up to section 70.

  The center device 1 is realized by a computer including a CPU and a storage device (not shown), and each processing unit constituting the center device 1 executes a predetermined program stored in the storage device. Is realized. The storage device includes a RAM, a nonvolatile memory, a hard disk device, and the like.

  The probe data receiving unit 10 receives probe data collected by the probe car. The center apparatus 1 and the probe car are connected by communication means such as an optical beacon, a wired LAN, a wireless LAN, a mobile phone, and a DSRC. The communication means by wired LAN here means that the probe data is stored in the storage device (hard disk, memory, etc.) provided in the probe car, the storage device is removed from the probe car, and connected to the home computer. This means that the home computer connects to the traffic information center through the Internet.

  It is assumed that the probe data is collected at regular time intervals or at regular intervals. The content of the probe data includes probe car unique ID information, position information of the probe car traveled, and time information at which the probe data is collected. The unique ID information of the probe car is information for identifying the vehicle that has collected the probe data, such as the vehicle number of the probe car and the serial number of the in-vehicle device mounted on the probe car. The position information is represented by latitude / longitude information measured by a GPS device mounted on the on-vehicle device of the probe car or a link ID of a road link traveled by the probe car. The link ID of the road link is a number defined for each portion (road link) delimited by road intersections or branch points in the map information mounted on the in-vehicle device. The road link can be specified by this number. The time information is information on the time when the position information is acquired.

  2A and 2B show the configuration of probe data received by the probe data receiving unit 10. The probe data in FIG. 2A is an example in which position information is composed of latitude / longitude information. FIG. 2B shows an example in which the position information of the probe data is configured with a link ID.

  The map data storage unit 14 stores road map electronic data. FIG. 3A shows the data structure of the road map stored in the map data storage unit 14. The road map is managed as a collection of road link data. Each road link data includes a link ID that can identify a road link, a node ID at the start of the road link and information on the latitude / latitude thereof, a node ID at the end and information on the latitude / longitude, the length of the road link, It consists of the number of other road links connected to the road link, the connection node ID of the connection node connected to the other road link, and the link ID of the road link connected to the connection node. FIG. 3B shows the data structure of the road link with the link ID 001, taking the road link shown in FIG. 3C as an example. The data in FIG. 3B shows that the road link with the link ID 001 has the start node ID of the start node 100 and the end node ID of the end node 200, and the start node has a road link with the link ID 002. This indicates that the road links having the link ID 003 are connected to the terminal nodes.

  The probe data processing unit 15 processes the probe data acquired from the probe data receiving unit 10 using the road map data stored in the map data storage unit 14 and stores it in the probe car travel history storage unit 20. The probe data received by the probe data receiving unit 10 is composed of position information and time information when the position information is acquired. At this time, it is necessary to convert the travel route of the probe car into a link train. When the position information of the probe data is latitude / longitude information, it is necessary to convert it into a travel route of a link row. First, the position information of one trip point from the start to the end of driving of the vehicle for which the probe data is collected is matched on the road link, and then the route search is performed so as to pass the matched point. Finally, the route search result is divided into link strings. When the position information of the probe data is a passed link ID, a route that sequentially passes through a route corresponding to each link ID is obtained by route search, and then decomposed into a link row. And the inflow time which flows into each link row | line | column which decomposed | disassembled the path | route is calculated | required.

  FIG. 4 shows a processing flow in which the probe data processing unit 15 converts probe data into link string data when the position information of the probe data is latitude / longitude information. This probe data processing is executed for the probe data for each vehicle received by the probe data receiving unit 10. First, road map data of a region to be processed is acquired from the map data storage unit 14 (step S10). For example, this area corresponds to a map mesh covering a rectangular area determined by the maximum and minimum values of latitude and longitude traveled by the target probe car. Next, the probe data of the vehicle to be converted into link string data is acquired from the probe data receiving unit 10 (step S20). The following processing is performed for each vehicle. Next, it is determined whether all the probe data of the target vehicle has been matched on the map (step S30). If the matching process has not been completed for all the probe data (No in step S30), the remaining probe data is matched on the map (step S40). In this matching process, a position (latitude / longitude) directly corresponding to the probe data is used as a probe point, and a perpendicular is drawn from this probe point to the surrounding road link. The road link having the shortest perpendicular length is determined as the road link matching the probe point. For probe data matched to a road link, the link ID of the matched road link, the point where the perpendicular foot intersects the road link (matching point), and the distance from the terminal node of the matched road link to the matching point Data is obtained.

  When all the probe data has been matched (Yes in step S30), the route search process is performed using the information of each matching point as a transit point to generate a travel route of the vehicle (step S50). Even if all the probe data is matched on the road, depending on the probe data collection interval and the link length of each road link, not all the road links matching the probe data are continuous. Therefore, by this route search process, the road of the road link (travel link) on which the vehicle that collected the probe data traveled is obtained by obtaining the travel route that passes through these waypoints in the order of the passage times corresponding to the matching points as the waypoints. A link ID can be obtained. The travel links obtained by this route search process include road links that do not correspond to matching points. The connection road link ID information stored in the map data storage unit 14 is used for the connection relation of the road links considered in the route search.

  Next, the average speed when traveling between the matching point corresponding to the probe data and the matching point of the next probe data is obtained from the road link that has traveled and the time information of the probe data, and the inflow / outflow of each link is determined. Time is obtained (step S60). The distance between two matching points is the length of each road link sandwiched between the road links corresponding to these two matching points on the travel route, and the end of the matched road link obtained at the time of matching to the matching point. It is determined by the distance. The time required to travel between two matching points is the difference in time information of probe data corresponding to each matching point. Here, assuming that the speed between the matching points is constant, the time at which the road link existing between the two matching points passes through the connection nodes (link start and end nodes) is obtained. Thereby, it is possible to obtain the link ID of the road link on which the probe car has traveled and the time of passing through the start / end nodes of the road link. Here, the time passing through the start node is referred to as inflow time, and the time passing through the end node is referred to as outflow time. Finally, the road link ID and the inflow / outflow time of the road link that has traveled are stored in the probe car travel history storage unit 20 (step S70).

  The above conversion process is performed in units of one trip for each vehicle. This one trip means traveling from the starting point to the destination point. For example, if you drive from home to work during the day and drive from work to work when returning from the office, you will have 2 trips (from home to work, from work to work), and each will be converted. . However, when the probe data acquired from the probe data receiving unit 10 is a link string, it is stored in the probe car travel history storage unit 20 as it is.

  The probe car travel history storage unit 20 accumulates the travel history converted by the probe data processing unit 15 from probe data to link string data. FIG. 5 shows the configuration of the probe car travel history storage unit 20. In the probe car travel history storage unit 20, a plurality of tables (travel history tables) for accumulating travel histories are configured for each vehicle ID. The table of each vehicle ID is stored for each trip, and is configured by pairing the link ID of the road link passed as the travel history and the inflow time to the road link. Here, the outflow time is the same as the inflow time of the next inflow road link, so it is not necessary to record it sometimes. At this time, link IDs are accumulated in order of inflow time. The start / end of one trip is identified by a trip start flag and a trip end flag that take special values. In order to divide the travel history for each trip, it is sufficient that either the trip start flag or the trip end flag is present. Since the travel history table is generated for each vehicle, the number of records differs depending on the travel distance of the vehicle. This probe car travel history storage unit 20 is stored offline. The above processing is performed offline.

  When the position information of the probe data is the link ID of the road link that has traveled, it is assumed that the matching point is at the midpoint of the road link in the process in S40, and the process in S60 may be performed. Also, when a link ID is sent as position information, if the inflow time to the road link corresponding to the link ID is sent as time information, the start end of this road link is assumed to be a matching point. The process of S60 may be performed. Alternatively, in addition to the link ID as position information, the distance from the link start end (or end) of the link corresponding to this link ID is sent, and the travel time (probe data collection time) of the point is sent as time information. In this case, as described above, the processing of S60 may be performed in the same manner as when the latitude / longitude information is sent as the position information.

  The sudden event occurrence information receiving unit 30 receives sudden event occurrence information such as traffic accidents, construction works, and events. Sudden event occurrence information includes notifications sent from accident witnesses, traffic information centers that distribute information on accidents and road construction, and reports sent from public organizations such as police that handle accidents, probe data, and road information Information from sensor data, or information detected using these probe data and road sensor data. The sudden event occurrence information includes the sudden event occurrence time corresponding to the time when the sudden event occurred, the sudden event occurrence road link ID which is the link ID of the road link where the sudden event occurred, and the lane direction of the road link affected by the sudden event (Upward / downward / both directions), the type of sudden event that occurred (accident, construction, event), and information indicating its magnitude (degree). For example, the fact that the upward lane of the sudden event occurrence point is affected is when there is an accident vehicle in the upward lane and it becomes difficult to travel in the upward lane. The sudden event occurrence location is the link ID of the road link that occurred or the position information of latitude and longitude. When the sudden event occurrence point is specified by the position information based on the latitude and longitude, it is converted to the link ID of the corresponding road link by the matching process described above. The acquired sudden event occurrence information is temporarily stored in the sudden event information storage unit 35 with the sudden event information reception time being the time when the sudden event occurrence information was received.

  The sudden event information storage unit 35 stores the sudden event information acquired from the sudden event occurrence information receiving unit. FIG. 6 shows the configuration of the sudden event information stored in the sudden event information storage unit 35. The information to be stored is the sudden event occurrence time, the sudden event information reception time, the sudden event occurrence road link ID, its direction, the sudden event type (accident, construction, event), and its size.

  The travel history search unit 40 searches the probe car travel history storage unit 20 for a trip including the link ID (sudden event occurrence link ID) of the road link where the sudden event acquired from the sudden event occurrence information receiving unit 30 has occurred. Output to the sudden event related table for each vehicle. FIG. 7 shows a conceptual diagram of the search for the sudden event occurrence link ID. The sudden event occurrence link ID “X” is searched from the link IDs of all trips recorded in the travel history table of each vehicle constituting the probe car travel history storage unit 20. When the link ID “X” is found, the trip including the link ID “X” is extracted.

  FIG. 8 shows the configuration of the sudden event related table for each vehicle that outputs the search result. The sudden event related table is composed of a matrix composed of an inflow road link ID indicating from which link the vertical axis has flowed in, and an outflow road link ID indicating which link has flowed out from the inflow link having passed through the horizontal axis. . The number of trips is input to the elements of this matrix.

  FIG. 9 shows a processing flow for creating a sudden event related table for each vehicle from the probe car travel history storage unit 20. Here, it is assumed that “X” is stored as the sudden event occurrence road link ID in the received sudden event information. First, a trip including the link ID “X” of the sudden event point is searched from the travel history table of each vehicle stored in the probe car travel history storage unit 20 (step S201), and the trip including the link ID “X” is searched. Are extracted (step S202). Next, a sudden event related table is created (step S203). This sudden event related table is a table of all extracted link trains, the vertical axis is the link ID of the inflow link and the horizontal axis is the link ID of the outflow link (total number of travel links × total number of travel links). It is. Here, it is assumed that the link ID of the inflow link and the link ID of the outflow link are arranged in the same order, and the index (the position of the row or column in the table) in the inflow link or the outflow link with the link ID “N” is indicated by Index N). Further, “0” is stored in all elements of this table for initialization. In the following, this element “0” is updated.

  Next, it is determined whether or not all the extracted trips have been processed (step S204). If all trips have been processed (Yes in step S204), the process ends. If all trips have not been processed (No in step S204), one new trip is selected, and the elements of the table whose index ID is “I” (Index (I), Index (I)) “1” is added to (step S205). For the selected trip, it is determined whether or not all link sequences arranged in chronological order have been processed (step S206). Here, the link ID that is the current processing target in the link string of trips is “I”. When all the link strings have been processed (Yes in step S206), the process returns to S204. If all the link strings have not been processed (No in step S204), whether or not there is a road link that has traveled next to the road link of the link ID “I” that is the target of processing in the target trip, that is, the next trip It is determined whether an end flag is set (step S207). If there is a next road link that has traveled (Yes in step S205), the link ID is “J”, and if it matches the Index (J) -th outflow link of the table, the element of the sudden event related table Add (1) to (Index (I), Index (J)) (element where the link ID of the inflow link is “I” and the link ID of the outflow link is “J”) (step S208), and the process returns to S206. When the next link ID does not exist, that is, when the trip end flag is set next (No in step S207), it is determined that the trip has ended on the road link with the link ID “I”, and the process returns to S204. The above processing is performed for all trips of the same vehicle.

  For example, if there is “1” in the (Index (0001), Index (0002)) element of the sudden event related table of the vehicle ID 00003, the link ID is “0001” in the trip of the vehicle ID “00003” in the search result. This means that there is one travel history that flows from a road link and travels on a road link with a link ID “0002”. When “1” is included in the elements of (Index (0001), Index (0001)), it means that the road link with the link ID “0001” is the road link at the start of the trip. Based on the search result of the probe car travel history storage unit 20, the sudden event related table is generated.

  The search for the sudden event occurrence link ID may be performed by adding conditions of the day type such as the same time, weekdays, and holidays. For example, when the sudden event occurrence time is “12:00” on weekdays, the trip time including the sudden event occurrence link ID from the probe car travel history storage unit 20 and the inflow time to the sudden event occurrence link is “12: Search for items containing "00". This search by time and day type is performed with reference to the inflow time and outflow time of the probe car travel history storage unit 20. Alternatively, it is possible to search for trips that flow into the sudden event occurrence link ID during a predetermined time interval including the sudden event occurrence time, assuming that the impact of the sudden event will continue for some time.

  The sudden event point passage frequency calculation unit 50 calculates the sudden event point passage frequency from the sudden event related table of each vehicle acquired from the travel history search unit 40, and generates a sudden event point passage frequency table. FIG. 10 shows a sudden event point passage frequency table. The sudden event point passage frequency table has the same format as the sudden event related table, and is an M × M table (M is the total number of link IDs included in the inflow link or outflow link in the sudden event point passage frequency table). It can be said that the outbreak link having a larger number of elements in the sudden event point passage frequency table is a road link having a higher pass frequency with respect to a vehicle passing through the sudden event point as seen from the accumulated travel history.

  FIG. 11 shows a processing flow for generating a sudden event point passage frequency table from the sudden event related table. First, a sudden event related table for each vehicle is acquired from the travel history search unit 40 (step S101). Then, it is determined whether or not all of the acquired incident related tables have been processed (step S102). If all the sudden event related tables have been processed (Yes in step S102), the process ends. If all the sudden event related tables have not been processed (No in step S102), a new next sudden event related table is selected from the remaining unprocessed sudden event related tables (step S103). Next, it is determined whether or not all the elements of the one incidental event association table being processed have been processed (step S104). When all elements of the sudden event related table being processed are processed (Yes in step S104), the process moves to S102. When processing is performed for the elements of the sudden event related table (No in step S104), one new element that has not yet been processed is selected from the current sudden event related table (step S105). Then, for the selected element, it is determined whether or not there is an element that matches the target inflow link / outflow link in the sudden event point passage frequency table (step S106). When the target element exists, that is, an element in which the link ID of the inflow link / outflow link is the same as the element selected from the sudden event relation table (Yes in step S106), The value of the element of the sudden event related table is added to the corresponding element of the sudden event point passage frequency table, and the process proceeds to S104 (step S108). On the other hand, if the target element does not exist (No in step S106), the corresponding element is added to the sudden event point passage frequency table, and the other elements in the row or column inserted along with the addition of the element are “0”. And move to S104 (step S107). When the first sudden event related table is processed, the sudden event point passage frequency table is the same as the first sudden event related table.

  FIG. 12 is a diagram illustrating the processing of steps S106, S107, and S108. When the element (Index (001), Index (X)) = 1 of the sudden event relation table is targeted, (Index (001), Index (X)) = 0 exists in the sudden event point passage frequency table. (Yes in step S106), 1 is added to the element to set (Index (001), Index (X)) = 1 (step S108). When elements (Index (009), Index (X)) = 1 of the sudden event related table are targeted, there is no element (Index (009), Index (X)) in the sudden event point passage frequency table. (No in step S106) After adding a row with the link ID 009 for the inflow link and filling the column element with “0” as an initial value, (Index (009), Index (X)) = 1 (Step S107).

  With the above processing flow, an unexpected event point passing frequency table is created in which the outflow frequency of the vehicle for each road link in the travel history of the probe car that has passed the point where the unexpected event has occurred is determined.

The passing frequency information generation unit 60 uses the sudden event information obtained from the sudden event information storage unit 35 and the sudden event point passage frequency table obtained from the sudden event point passage frequency calculation unit 50 to identify the point where the sudden event has occurred in the past. Passage frequency information for each road link based on the travel history of the probe car that has passed is generated. FIG. 13 shows a schematic diagram of generation of passing frequency information. The passing frequency information is obtained by normalizing the total number of vehicles spilled to each road link by the number of spills to the sudden event occurrence road link (link ID “X”) obtained from the sudden event point passage frequency table. . The sudden event point passage frequency table is a table having a size of M × M, and the elements whose link ID of the inflow link is “i” and whose link ID of the outflow link is “j” are (Index (i), Index (j )), When the numerical value of the element is T (Index (i), Index (j)), the passing frequency Z (j) of the outflow link “j” is
Z (j) = (T (1, Index (j)) + T (2, Index (j)) + ... + T (M, Index (j))))
/(T(1,Index(X))+T(2,Index(X))+...+T(M,Index(X))))
... (Formula 1)
It is.

  FIG. 14 is a diagram showing a processing flow for generating passage frequency information from the sudden event point passage frequency table. First, a sudden event passing frequency table corresponding to the sudden event is acquired (step S301). Next, it is determined whether or not all the outflow links in the sudden event passage frequency table have been processed (step S302). When all the outflow links have not been processed (No in step S302), one road link to be processed is selected from the remaining outflow links that have not yet been processed, and all inflows for the outflow links to be processed are selected. The total number is obtained by adding the number of passing vehicles from the link (step S303). When all the outflow links have been processed (Yes in step S302), the total value of the number of passing through the other outflow links is normalized by the total number of passing through the outflow links at the sudden event point (step S304). This is the process of (Formula 1).

  FIG. 15 is a diagram showing the format of the passage frequency information. The passing frequency information includes a link ID of a road link and a passing frequency of the road link. The passing frequency of the road link where the sudden event has occurred is “1”. And the road link where this passing frequency becomes a large value is a road link with a high ratio that the vehicle which passed the sudden event occurrence point traveled. The passing frequency information of the sudden event point represents the ratio of the number of vehicles heading to the sudden event point. And as the road link is closer to the sudden event point, the passing frequency tends to increase. A road link with a high passing frequency is likely to be affected after the occurrence of the sudden event because the number of vehicles heading to the sudden event point is large. For this reason, it can be said that there is a correlation between the passing frequency of the sudden event point and the degree to which the surrounding road link after the sudden event is affected. If the degree of impact represents the influence of each road link that may be congested when an unexpected event occurs, the frequency of passage can be regarded as the degree of influence.

  As described above, by determining the passage frequency information, it is possible to determine the degree of influence of the surrounding road link at the sudden event occurrence point.

  The passing frequency information transmitting unit 70 transmits the passing frequency information acquired from the passing frequency information generating unit 60 to the in-vehicle terminal device 100. This transmission method is based on communication such as wireless LAN, mobile phone, DCRC, or broadcast such as FM broadcast or terrestrial digital broadcast.

  The above processing is performed as online processing after receiving the sudden event information.

  The in-vehicle terminal device 100 receives the passing frequency information transmitted from the passing frequency information transmitting unit 70 and displays the sudden event information. FIG. 16 is a configuration diagram of the in-vehicle terminal device 100. The in-vehicle terminal device 100 includes processing units such as a passing frequency information receiving unit 110, a passing frequency information storage unit 120, a passing frequency information display unit 130, a road cost storage unit 140, a route search unit 150, and a road cost update unit 160. It consists of

  The passing frequency information receiving unit 110 receives the passing frequency information transmitted from the passing frequency information transmitting unit 70 of the center device 1 and stores it in the passing frequency information storage unit 120. The passing frequency information storage unit 120 stores sudden event information in the same format as in FIG.

  The passing frequency information display unit 130 receives the passing frequency information from the passing frequency information storage unit 120, and displays the passing frequency information on a display (not shown) of the in-vehicle terminal device 100. FIG. 17 is a diagram illustrating an example of when the on-vehicle terminal device 100 displays sudden event information and pass frequency information of road links around the sudden event occurrence point. Levels are displayed in red, orange, green, etc. according to the frequency of passing for each road link and displayed. In addition to this, there are display methods such as changing the hue / saturation / lightness of the line, changing the line type, and the like. In addition, even when the display area of the map is changed by scrolling the map from the own vehicle position, for example, in order to see the sudden event information and the passing frequency information of an area somewhat distant by the display processing of such passing frequency information, Similarly, the passage frequency is displayed for each sudden event information.

  The road cost storage unit 140 is used when searching for a route in the in-vehicle terminal device 100. The road cost stored here is a numerical value of a road-specific length, ease of travel, transit time predicted from current and past traffic information, and the like. FIG. 18 shows a configuration diagram of the road cost storage unit. The road cost is managed in map mesh units, and includes a link ID belonging to the map mesh and the link cost. The map mesh is a method of partitioning a map on a mesh based on latitude and longitude. The secondary mesh is mesh data having a latitude difference of 5 minutes, a longitude difference of 7 minutes 30 seconds and a side length of about 10 km. The tertiary mesh is an area formed by dividing the secondary mesh into 10 equal parts in the latitude direction and the longitude direction. The latitude difference is 30 seconds, the longitude difference is 45 seconds, and the length of one side is about 1 km. In addition to map meshes, road costs may be managed by a set of multiple links. In addition to map meshes such as secondary meshes, tertiary meshes, and quaternary meshes, administrative districts such as prefectures It is also possible to manage road costs in units of road types such as highways, urban highways, national roads, general roads, or combinations thereof.

  In the in-vehicle terminal device 100, the route search unit 150 sets a destination using the input unit 170, and searches for a route to the destination using the road cost updated by the road cost update unit 160. For the route search to the destination, the road link of the route that minimizes the sum of all the road link costs is selected from a plurality of route candidates.

  The road cost update unit 160 updates the road cost from the road cost storage unit 140 and the passage frequency information storage unit 120, and transmits the updated road cost to the route search unit.

  FIG. 19 shows a processing flow in which the pass frequency information is reflected in the road cost data during route search. First, the route search unit 150 sets a destination specified by the input unit 170 to search for a route from the vehicle position (step S401). At this time, the in-vehicle terminal device 100 has the destination as a road link ID. Next, the road cost update unit 160 acquires road cost data stored in the road cost storage unit 140 (step S402). This road cost data is acquired for each road mesh. At this time, the road mesh acquired from the road cost storage unit 140 is the map mesh passing from the vehicle position to the destination and its surroundings. For example, a map mesh in a range covering a rectangular area having a road link corresponding to each of the vehicle position and the destination as diagonal vertices is acquired. Further, one link ID is selected from the acquired road costs. Next, the link ID of the road link included in one of the map meshes acquired from the road cost storage unit 140 by the process of step S402 from the pass frequency information stored in the pass frequency information storage unit 120. For the road link that matches, the link ID and the passing frequency are acquired (step S403).

  Next, in step S403, it is determined whether all link IDs included in the road cost acquired from the road cost storage unit 140 have been processed (step S404). When all the link IDs have been processed (Yes in step S404), the process of reflecting the pass frequency information in the road cost data is terminated.

  If all link IDs have not been processed (No in step S404), it is determined whether the link ID selected from the road cost data matches any of the road link link IDs included in the passing frequency information. (Step S405). If they do not match (No in step S405), the link ID of the road cost data to be processed next is selected, and the process proceeds to step S404. If they match (Yes in step S405), the road frequency information is converted and reflected in the road cost data (step S406). Here, the passing frequency information of the matched link ID is converted into a link cost corresponding to the link ID in the road link. The passing frequency for each link ID is converted into a link cost by multiplying the value by a constant. For example, when the passing frequency of a road link with a matching link ID is “0.5”, the link cost is set to “5” by multiplying the value by 10. Further, the sum of the link cost converted from the passing frequency and the link cost data in the road cost acquired in step S402 is taken as a new link cost of the corresponding road link. Next, the process proceeds to step S404. With the above processing flow, the road cost reflecting the passing frequency information can be obtained.

  In the above processing flow, when the road cost data converted from the pass frequency information is large and the route search is performed using the cost data, the in-vehicle terminal device 100 provides the driver with a detour route of the sudden event point. Can do.

  According to the embodiment described above, it is possible to obtain the passing frequency of the peripheral links at the sudden event occurrence point using the traveling history of the probe car. Furthermore, by distributing this passing frequency information to the in-vehicle terminal device 100, it is possible to present a road link that is easily affected after a sudden event occurs to the user. The user looks at this passing frequency information and decides a detour route for driving, and the in-vehicle terminal device 100 efficiently reflects the passing frequency information in the cost data of the road for the route search, thereby efficiently detecting the sudden event point. Can be avoided.

1 is an overall view of a traffic information system. It is a figure which shows the structure of probe data. It is the figure which showed the structure of the map data storage part. It is the figure which showed the processing flow converted from probe data to link row data. It is the figure which showed the structure of the probe car travel history memory | storage part. It is a figure explaining the data structure of sudden event information. It is a conceptual diagram of search of sudden event occurrence link ID. It is the figure which showed the structure of the sudden event related table. It is the figure which showed the processing flow which produces a sudden event related table from a probe car travel history memory | storage part. It is the figure which showed the sudden event point passage frequency table. It is the figure which showed the processing flow which produces | generates a sudden event point passage frequency table. It is a figure explaining the production | generation procedure of the sudden event point passage frequency table. It is a figure explaining the production | generation of passage frequency information. It is the figure which showed the processing flow which produces | generates passage frequency information from a sudden event point passage frequency table. It is a figure which shows the structure of passage frequency information. It is a block diagram of a vehicle-mounted terminal device. It is the figure which showed the example of a display of sudden event information and the passage frequency information of a road link to a vehicle-mounted terminal device. It is a figure which shows the structure of a road cost. It is the figure which showed the processing flow which reflects passage frequency information on the road cost data at the time of route search.

Explanation of symbols

1 Center Device 10 Probe Data Receiving Unit 14 Map Data Storage Unit 15 Probe Data Processing Unit 20 Probe Car Travel History Storage Unit 30 Sudden Event Occurrence Information Receiving Unit 35 Sudden Event Information Storage Unit 40 Travel History Searching Unit 50 Sudden Event Point Passing Frequency Calculation Unit 60 Passage frequency information generation unit 70 Passage frequency information transmission unit 100 In-vehicle terminal device 110 Passage frequency information reception unit 120 Passage frequency information storage unit 130 Passage frequency information display unit 140 Road cost storage unit 150 Route search unit 160 Road cost update unit

Claims (8)

In the traffic information center,
Receive and accumulate travel history information and sudden event occurrence information sent by the probe car,
From the accumulated traveling history information of the probe car, the traveling history information including the road link where the sudden event has occurred is extracted.
Find the frequency of travel on each road link included in the extracted travel history information,
Generate the passing frequency information obtained by normalizing the traveling frequency of each road link by the total number of probe cars passing through the road link where the sudden event occurred,
Deliver the passing frequency information to the in-vehicle terminal device,
The in-vehicle terminal device displays the passing frequency information.   2. The traffic information display method according to claim 1, wherein the travel history information of the probe car is accumulated for each combination of a departure place and a destination for each probe car.   In Claim 1, when extracting the traveling history information including the sudden event occurrence point from the traveling history information of the probe car, the traveling history information corresponding to the specified weekday / holiday type and time zone is obtained. A traffic information display method characterized by extracting.   In Claim 1, when displaying the said passage frequency information on the said vehicle-mounted terminal device, according to the level of the passage frequency of a road link, it displays by changing the color, the saturation, and the brightness of the line of the said road link. A traffic information display method characterized by: A traffic information center comprising a plurality of probe cars for transmitting travel history information, an unexpected event information receiving device for receiving occurrence information of sudden events, and a travel history information storage device for storing travel history information from the probe cars In the traffic information system consisting of
The traffic information center
A sudden event occurrence point extraction device that extracts travel history information including a road link where the sudden event has occurred from the travel history information storage device;
The driving frequency is obtained for each road link included in the driving history information extracted from the sudden event occurrence point extraction device, and the driving frequency for each road link is the total number of probe cars that have passed through the road link where the sudden event has occurred. A passing frequency information generating device that generates passing frequency information normalized by
A frequency information distribution device for distributing the passing frequency information to the in-vehicle terminal device;
With
The on-vehicle terminal device includes a display device that displays the passing frequency information received from the frequency information distribution device.   6. The traffic information system according to claim 5, wherein the travel history information storage device stores travel history information for each combination of a departure place and a destination for each probe car.   6. The sudden event occurrence point extraction device according to claim 5, wherein the sudden event occurrence point extraction device has a function of designating a weekday / holiday day type and time zone in order to extract a travel history including the sudden event occurrence point from the travel history information storage device. A traffic information system characterized by this. 6. The display device according to claim 5, wherein the display device displays the passage frequency information on the in-vehicle terminal device according to the road link passage frequency according to the level of the road link line color, saturation, and brightness. A traffic information system characterized by having a function of changing the display.

Images