Information processing device, information processing method, and computer program

Abstract

According to one aspect of the present disclosure, a device comprises: a storage unit that stores probe information about a probe vehicle that travels an approach to an intersection; and an information processing unit that executes determination processing for whether there is pulsation at the approach. The determination processing includes: processing that generates time series data for a delay indicator that is a traffic indicator that is calculated from the probe information and indicates the degree of delay in vehicle traffic caused by waiting for a signal; and processing that determines whether there is pulsation on the basis of the time series data for the delay indicator.

Description

Technical Field

[0001] This disclosure relates to an information processing apparatus, an information processing method, and a computer program. This application claims priority based on Japanese Application No. 2021-185181 filed on November 12, 2021, and incorporates all the descriptions described in the said Japanese application.

Background Art

[0002] Patent Document 1 describes a traffic signal control device that controls traffic signals included in one sub-area with a common cycle length. This traffic signal control device includes a determination means for determining whether or not to combine at least two adjacent sub-areas based on an evaluation value considering the influence of pulsations in each case where at least two adjacent sub-areas are combined and where they are not combined.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] An apparatus according to one aspect of this disclosure includes a storage unit that stores probe information of probe vehicles passing through inflow roads to an intersection, and an information processing unit that executes a determination process for the presence or absence of pulsations in the inflow roads. The determination process includes a process of generating time-series data of a delay index, which is a traffic index representing the degree of delay of vehicle passage due to signal waiting, calculated from the probe information, and a process of determining the presence or absence of the pulsations based on the time-series data of the delay index.

[0005] A method according to one aspect of the present disclosure is an information processing method performed by an information processing device, comprising the steps of: storing probe information of a probe vehicle traveling on an inflow road to an intersection; and performing a determination process for the presence or absence of pulsation in the inflow road, wherein the determination process includes: generating time-series data of a delay index, which is a traffic index representing the degree of delay in vehicle traffic due to waiting at traffic lights, calculated from the probe information; and determining the presence or absence of pulsation based on the time-series data of the delay index.

[0006] A computer program according to one aspect of the present disclosure is a computer program for causing a computer to function as a storage unit for storing probe information of a probe vehicle traveling on an inflow road to an intersection, and an information processing unit for performing a determination process for the presence or absence of pulsation on the inflow road, wherein the determination process includes a process for generating time-series data of a delay index, which is a traffic index representing the degree of delay in vehicle traffic due to waiting at traffic lights, calculated from the probe information, and a process for determining the presence or absence of pulsation based on the time-series data of the delay index.

[0007] This disclosure can be implemented not only as a system and apparatus having the characteristic configuration described above, but also as a program for causing a computer to execute such characteristic configuration. Furthermore, this disclosure can be implemented as a semiconductor integrated circuit that implements part or all of the system and apparatus. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an overall diagram of the traffic signal control system. [Figure 2] Figure 2 is a block diagram of the information processing unit, the on-board equipment of the probe vehicle, and the central unit included in the traffic signal control system. [Figure 3] Figure 3 is an explanatory diagram showing an example of a road link where pulsation may occur. [Figure 4] Figure 4 is a time chart showing the reasons for pulsation in the first link. [Figure 5]Figure 5 is a time chart showing the reasons for pulsation in the second link. [Figure 6] Figure 6 is a graph showing an example of the travel trajectory when multiple vehicles travel along a road link. [Figure 7] Figure 7 is an explanatory diagram illustrating an example of a stop event that affects the accuracy of delay time based on the average travel time of the link. [Figure 8] Figure 8 is an explanatory diagram showing an example of the definition of variables used to calculate the average travel time in a section where traffic lights are being stopped. [Figure 9] Figure 9 is a flowchart showing an example of the process for calculating the delay time per vehicle due to waiting at a traffic light. [Figure 10] Figure 10 is a flowchart showing an example of the process for calculating the total number of sections within a signal waiting zone. [Figure 11] Figure 11 is an explanatory diagram showing an actual example of calculating the total number of intervals. [Figure 12] Figure 12 is a flowchart showing an example of the process for determining the presence or absence of pulsation. [Figure 13] Figure 13 is a graph showing an example of time-series data for delay time. [Figure 14] Figure 14 is a flowchart showing another example of the process for determining the presence or absence of pulsation. [Figure 15] Figure 15 is a graph showing an example of time-series data for queue length. [Modes for carrying out the invention]

[0009] <Issues this disclosure aims to address> Conventional traffic signal control systems calculate evaluation values ​​that take into account the effects of pulsation by reproducing actual traffic conditions in a traffic simulator. Therefore, it is necessary to configure the road network and adjust parameters for the traffic simulator, which is a time-consuming process. In addition, in a traffic simulator, since the signal control parameters (cycle length, split, etc.) of each sub - area required for calculating the evaluation value are determined from the traffic jam length and saturation based on the detection signal of the vehicle detector, it cannot be applied to roads where no vehicle detector is installed.

[0010] In view of such conventional problems, an object of the present disclosure is to enable determination of the occurrence situation of pulsation regardless of the presence or absence of a vehicle detector.

[0011] <Effect of the Present Disclosure> According to the present disclosure, it is possible to determine the occurrence situation of pulsation regardless of the presence or absence of a vehicle detector.

[0012] <Outline of Embodiment of the Present Disclosure> The outline of the embodiment of the present disclosure will be listed and described below. (1) The information processing apparatus of the present embodiment includes a storage unit that stores probe information of probe vehicles passing through the inflow roads to an intersection, and an information processing unit that executes determination processing on the presence or absence of pulsation in the inflow roads. The determination processing includes a process of generating time - series data of a delay index, which is a traffic index representing the degree of delay of vehicle passage due to signal waiting, calculated from the probe information, and a process of determining the presence or absence of the pulsation based on the time - series data of the delay index.

[0013] According to the information processing apparatus of the present embodiment, since the information processing unit determines the presence or absence of pulsation in the inflow roads of the intersection based on the time - series data of the delay index calculated from the probe information, it is possible to determine the occurrence situation of pulsation regardless of the presence or absence of a vehicle detector.

[0014] (2) In the information processing apparatus of the present embodiment, as the delay index, for example, the delay time per vehicle due to signal waiting, calculated from the average travel time of the signal - waiting section in the inflow road, can be adopted.

[0015] The reason is that when the fluctuation of the above - mentioned delay time has periodicity, it can be estimated that pulsation has occurred. Furthermore, since the delay time is calculated from the average travel time of the signal waiting section, unlike when the delay time is calculated from the average travel time of the link, it is possible to calculate an accurate delay time that is less likely to include stopping events other than signal waiting. Therefore, it is possible to accurately determine whether or not there is pulsation.

[0016] (3) In the information processing device of this embodiment, the average travel time of the signal waiting section may be calculated by the following formula (1).

number

[0017] In this case, the average travel time for the above-mentioned signal waiting section can be accurately calculated using equation (1).

[0018] (4) In the information processing device of this embodiment, the delay index may be calculated by the following formula (2).

number

[0019] In this case, the above delay time can be accurately calculated using equation (2).

[0020] (5) In the information processing apparatus of this embodiment, the storage unit stores a time threshold for signal waiting to identify whether the inflow path is saturated or unsaturated, and the information processing unit may determine the periodic occurrence of a peak in the delay time that is greater than or equal to the time threshold as pulsation.

[0021] The reason is that if the delay time is below the above-mentioned time threshold, it is a non-saturated state in which no unresolved traffic occurs at the end of the blue time. Therefore, even if the delay time changes within the range below the time threshold, it cannot be said to be a pulsation that exacerbates delays and stops in vehicle traffic.

[0022] (6) In the information processing device of this embodiment, for example, the queue length due to signal waiting in the inflow path can be adopted as the delay index.

[0023] The reason for this is that if there is a periodicity in the fluctuations of the queue length mentioned above, it can be inferred that pulsation has occurred.

[0024] (7) In the information processing device of this embodiment, the queue length may be calculated by the following formula (3).

number

[0025] In this case, the queue length can be accurately calculated using equation (3).

[0026] (8) In the information processing apparatus of this embodiment, the storage unit stores a distance threshold for signal waiting to identify whether the inflow path is saturated or unsaturated, and the information processing unit may determine the periodic occurrence of a peak in the queue length that is greater than or equal to the distance threshold as pulsation.

[0027] The reason is that when the queue length is less than the distance threshold mentioned above, it is a non-saturated state in which no unprocessed traffic occurs at the end of the blue time. Therefore, even if the queue length changes within the range below the distance threshold, it cannot be said to be a pulsation that exacerbates delays and stops in vehicle traffic.

[0028] (9) The calculation method of this embodiment is an information processing device executed by the information processing devices described in (1) to (8) above. Therefore, the information processing device of this embodiment has the same effects as the information processing devices described in (1) to (8) above.

[0029] (10) The computer program of this embodiment is a computer program that causes the computer to function as an information processing device as described in (1) to (8) above. Therefore, the computer program of this embodiment has the same effects as the information processing devices described in (1) to (8) above.

[0030] <Details of Embodiments of the Invention> The embodiments of the present invention will be described in detail below with reference to the drawings. At least some of the embodiments described below may be combined in any way.

[0031] [Definition of Terms] Before describing the details of this embodiment, we will first define the terms used in this specification. "Vehicle": This refers to all vehicles that travel on roads. Therefore, in addition to automobiles, light vehicles, and trolleybuses, motorcycles are also included as vehicles. The drive system of a vehicle is not limited to internal combustion engines; electric vehicles and hybrid cars are also included. In this embodiment, the term "vehicle" includes both probe vehicles equipped with on-board devices capable of transmitting probe information and ordinary vehicles that do not provide probe information to external parties.

[0032] "Probe information" refers to various types of information about a vehicle sensed by a probe vehicle while it is traveling on a road. Probe information is also called probe data or floating car data. Probe information may include vehicle data such as the identification information of the probe vehicle, vehicle position, vehicle speed, direction of travel, and the time of occurrence of these events. Probe information may also utilize information such as position and acceleration acquired from smartphones or tablets inside the vehicle.

[0033] "Probe vehicle": This refers to a vehicle that senses probe information and transmits it externally. Vehicles traveling on roads include both probe vehicles and other types of vehicles. However, even ordinary vehicles that do not have an in-vehicle device capable of transmitting probe information are included in the category of probe vehicles if they have a smartphone, tablet PC, or similar device capable of transmitting probe information such as the vehicle's location to an external source.

[0034] "Signal control parameters": The term "signal control parameters" collectively refers to the temporal elements of signal representation: cycle length, split, and offset. They are also called signal control constants. "Cycle length": This refers to the time of one cycle, from the start of a green (or red) light in a traffic signal to the start of the next green (or red) light. In Japan, however, the green color of the traffic signal light is actually referred to as "blue" by law.

[0035] "Split": This refers to the ratio of the length of time allocated to each indication to the cycle length. It is generally expressed as a percentage or ratio. More precisely, it is the value obtained by dividing the effective blue time by the cycle length. "Offset": In system control or regional control, this refers to the deviation of a signal display at a certain point in time, for example, the start time of the green light on a main road, from a common reference point for the group of traffic lights, or the deviation of the same display start point between adjacent intersections. The former is called absolute offset, and the latter is called relative offset, and is expressed as a percentage of time (seconds) or period.

[0036] "Green light period": This refers to the period of time during which vehicles have the right of way at an intersection. The end of the green light period can be set as follows: at the earliest, when the green light turns off; at the latest, when the yellow light turns off. In the case of intersections with arrow signals, it can also be set as the end of the right-turn arrow. "Red light period": This refers to the time period during which vehicles do not have the right of way at an intersection. The start time of the red light period can be set as follows: at the earliest, when the green light turns off; at the latest, when the yellow light turns off. In the case of intersections with arrow signals, it can also be set as the end of the right-turn arrow.

[0037] As described above, in this embodiment, the time period included in one cycle is broadly divided into blue time (when there is a right of way) and red time (when there is no right of way). Therefore, if we let the blue time be G, the red time be R, and the cycle length be C, then the relationship C = G + R holds. Therefore, in the following explanation, R may be replaced with (CG). That is, the red time R may be a value indirectly calculated from the cycle length C and the blue time G.

[0038] "Queue": This refers to a line of vehicles stopped before an intersection, such as waiting at a red light. The length of the queue (in meters) is called the "queue length." "Link": This refers to a section of road that connects nodes such as intersections, and has an uphill or downhill direction. It is also called a road link. A link that flows inward towards an intersection is called an inflow link, and a link that flows outward from an intersection is called an outflow link.

[0039] "Travel time": This refers to the time it takes for a vehicle to travel a certain distance. Travel time may include stopovers and delays. "Link travel time": This refers to the travel time when the road section used as the unit for calculating travel time is a "link," that is, the travel time required for a vehicle to travel from the beginning to the end of a single link.

[0040] "Traffic volume" refers to the number of vehicles passing through a given time period. Unless otherwise specified, it is expressed as the number of vehicles passing over one hour. However, for control and evaluation purposes, shorter time periods such as seconds, 5 minutes, or 15 minutes may be used. Generally, traffic volume increases in response to traffic demand, but decreases when traffic demand exceeds traffic capacity.

[0041] "Supersaturated, Unsaturated, Near-Saturated": When there are still queues of people waiting at the signal when the green light ends, traffic demand exceeds traffic capacity. This state is called a "supersaturated state." Conversely, a state where traffic demand is less than or equal to traffic capacity, and the queue for traffic lights clears when the green light ends, is called a "non-saturated state." A state that is not supersaturated but has a high demand rate (for example, 0.85 or higher) is called near-saturated. The demand rate is less than 1.

[0042] "Delay Index": This refers to a traffic index that indicates the degree of delay in vehicle traffic due to waiting at traffic lights. The unit of the delay index may be either time or length. Therefore, a delay index with units of time represents the delay time for vehicle traffic caused by waiting at traffic lights, while a delay index with units of length represents the queue length caused by waiting at traffic lights.

[0043] [Overall System Configuration] Figure 1 is an overall configuration diagram of the traffic signal control system 1 according to this embodiment. Figure 2 is a block diagram of the information processing device 2, the on-board device 4 of the probe vehicle 3, and the central device 5 included in the traffic signal control system 1. As shown in Figures 1 and 2, the traffic signal control system 1 includes an information processing device 2 installed in a data center or the like, an on-board device 4 mounted on a probe vehicle 3, a central device 5 installed in a traffic control center, and traffic signal controllers 6 installed at each intersection.

[0044] The traffic signal control system 1 of this embodiment is a system in which an information processing device 2 collects probe information including the vehicle position and the time of its passage from a probe vehicle 3, and also acquires signal information for intersections from a central device 5 or the like, and uses the probe information and signal information to estimate the occurrence of pulsation in the entrance road of the intersection.

[0045] The entity operating the information processing device 2 is not particularly limited. For example, the entity operating the information processing device 2 may be the manufacturer of the vehicle 3 or an IT company that provides various information services, or it may be a public operator responsible for traffic control that operates the central device 5. The server of the information processing device 2 may be operated as either an on-premises server or a cloud server.

[0046] The onboard device 4 of the probe vehicle 3 is capable of wireless communication with wireless base stations 7 (for example, mobile phone base stations) in various locations. The wireless base stations 7 can communicate with the information processing device 2 via a public communication network 8 such as the internet. Therefore, the in-vehicle device 4 can wirelessly transmit uplink information S1 addressed to the information processing device 2 to the wireless base station 7. In addition, the information processing device 2 can transmit downlink information S2 addressed to a specific in-vehicle device 4 to the public communication network 8.

[0047] [Configuration of the information processing device] As shown in Figure 2, the information processing device 2 comprises a server computer 10 and multiple databases 21 to 24 built on the server computer 10. The server computer 10 comprises an information processing unit 11, a storage unit 12, and a communication unit 13. Databases 21-24 are electronic data constructed in the storage unit 12 in a predetermined data arrangement. However, some or all of databases 21-24 may be constructed in an external storage device (not shown) connected to the server computer 10.

[0048] The information processing unit (hereinafter also referred to as the "processing unit") 11 is an arithmetic processing unit that includes a CPU (Central Processing Unit) and RAM (Random Access Memory). The processing unit 11 may also include an integrated circuit such as an FPGA (Field-Programmable Gate Array). The processing unit 11 reads the computer program 14 stored in the memory unit 12 into the main memory (RAM) and performs various information processing operations according to the program 14.

[0049] The storage unit 12 is an auxiliary storage device that includes at least one non-volatile memory (recording medium) from among HDD (Hard Disk Drive) and SSD (Solid State Drive). The storage unit 12 may include flash ROM (Read Only Memory), USB (Universal Serial Bus) memory, or an SD card.

[0050] The computer program 14 of the information processing device 2 includes a program that causes the processing unit 11 to perform information processing such as calculating the delay time of the probe vehicle 3 due to waiting at traffic lights, and determining whether or not there is pulsation in the road link using the delay time.

[0051] The communication unit 13 is a communication interface that communicates with the central device 5 and the radio base station 7 via the public communication network 8. The communication unit 13 can receive uplink information S1 from the radio base station 7 and can transmit downlink information S2 to the radio base station 7. Uplink information S1 includes probe information transmitted by the in-vehicle device 4. Downlink information S2 includes the link travel time calculated by the processing unit 11.

[0052] The communication unit 13 is capable of receiving signal information for intersections included in the traffic control area, which is transmitted to it by the central device 5. The signal information for the intersections includes at least the cycle length and redlight duration of the intersection. The communications unit 13 may be connected to the central equipment 5 of the traffic control center via a dedicated communications line 9, rather than via the public communications network 8.

[0053] Multiple databases 21-24 include a map database 21, a probe database 22, a member database 23, and a signal information database 24. Map database 21 contains road map data 25 that covers the entire country. Road map data 25 includes "intersection data" and "link data".

[0054] "Intersection data" is data that associates intersection IDs assigned to intersections in Japan with location information of those intersections. "Link data" consists of data that associates the following information 1) to 4) with link IDs of specific links assigned to roads in Japan. Information 1) Location information of the start, end, and interpolation points of a specific link. Information 2) Link ID connected to the starting point of a specific link Information 3) Link ID connected to the endpoint of a specific link Information 4) Link cost of specific links

[0055] The road map data 25 constitutes a network corresponding to the actual road alignment and the direction of travel on the roads. Therefore, the road map data 25 is a network in which road sections between nodes n representing intersections are connected by directed links l (lowercase L). Specifically, the data structure of the road map data 25 includes a directed graph in which nodes n, set for each intersection, are connected by a pair of reverse-directed links l. Therefore, in the case of a one-way road, only one-way directed links l connect nodes n.

[0056] The road map data 25 also includes road type information indicating whether a specific directed link l corresponding to each road on the map is a general road or a toll road, as well as facility information indicating the type of facility included in the directed link l, such as toll booths or parking areas.

[0057] The probe database 22 stores probe information received from probe vehicles 3 that have been pre-registered in the information processing device 2, categorized by the identification information of each vehicle 3. The accumulated probe information includes at least the vehicle position and the time it passed. The probe information may also include vehicle data such as vehicle speed, vehicle orientation, and vehicle status information (stop / drive events). The sensing period for the probe information is granular enough to accurately identify the driving history of probe vehicle 3, for example, 0.5 to 1.0 seconds.

[0058] The member database 23 records personal information of the owner (registered member) of the probe vehicle 3, such as their address and name, the vehicle identification number (VIN), and identification information of the in-vehicle device 4 (for example, at least one of the following: MAC address, email address, and telephone number). The signal information database 24 stores signal information, including the cycle length and red time length of the entry lanes for each intersection, for each intersection ID and link ID.

[0059] The traffic signal controllers 6 installed at each intersection in the traffic control area include two types of traffic signal controllers: the first controller 6A and the second controller 6B. First controller 6A: A traffic signal controller that is not subject to remote control (system control and area control, etc.) by the central device 5, but performs point control (fixed-period control, etc.) to determine the color of the signal lights independently. Second controller 6B: Traffic signal controller that is subject to remote control (system control and area control, etc.) by the central unit 5.

[0060] The central device 5 transmits the signal information of the first controller 6A to the information processing device 2 only when the operation has changed. The processing unit 11 updates the signal information of the first controller 6A contained in the signal information database 24 with the received signal information. The central device 5 transmits the signal information of the second controller 6B to the information processing device 2 at predetermined control cycles (e.g., 1.0 to 2.5 minutes). The processing unit 11 updates the signal information of the second controller 6B contained in the signal information database 24 with the received signal information.

[0061] [Configuration of the in-vehicle device] As shown in Figure 2, the in-vehicle device 4 consists of a computer device equipped with a processing unit 31, a storage unit 32, a communication unit 33, and the like. The processing unit 31 is an arithmetic processing unit including a CPU and RAM. The processing unit 31 reads the computer program 34 stored in the storage unit 32 and performs various information processing according to the program 34.

[0062] The storage unit 32 is an auxiliary storage device that includes at least one non-volatile memory (recording medium) from among HDD and SSD. The storage unit 32 may also include flash ROM, USB memory, or SD card. The computer program 34 of the in-vehicle device 4 includes a program that causes the CPU of the processing unit 31 to perform tasks such as sensing and generating probe information, route search processing for the probe vehicle 3, and image processing for displaying the search results on the navigation device's display.

[0063] The communication unit 33 is a wireless communication device such as a gateway permanently installed in the vehicle 3, or a data communication terminal (for example, a smartphone, tablet computer, or node-type personal computer) temporarily installed in the vehicle 3. The communication unit 33 includes, for example, a GNSS (Global Navigation Satellite System) receiver. The processing unit 31 monitors the vehicle's current position in near real-time based on the GNSS position information received by the communication unit 33. Positioning is preferably performed using a global navigation satellite system such as GNSS, but other methods may also be used.

[0064] The processing unit 31 measures vehicle data such as the vehicle's position, vehicle speed, vehicle orientation, and CAN (Controller Area Network) information at predetermined sensing intervals (e.g., 0.5 to 1.0 seconds) and records it in the storage unit 32 along with the measurement time. When vehicle data is stored in the storage unit 32 for a predetermined recording time (for example, 1 minute), the communication unit 33 generates probe information containing the stored vehicle data and identification information of its own vehicle, and transmits the generated probe information uplink to the information processing device 2.

[0065] The in-vehicle device 4 includes an input interface (not shown) that accepts driver input. The input interface consists of, for example, an input device attached to a navigation system, or an input device of a data communication terminal mounted on the probe vehicle 3.

[0066] [Configuration of the central unit] As shown in Figure 2, the central unit 5 consists of a server computer that comprehensively controls the traffic signal controllers 6 at multiple intersections included in the traffic control area. The central unit 5 includes a processing unit 51, a storage unit 52, a communication unit 53, and the like.

[0067] The traffic signal controller 6 within the traffic control area includes a first controller 6A that operates independently (standalone) using a point-control method, and a second controller 6B that is controlled remotely by the central device 5. The processing unit 51 is an arithmetic processing unit including a CPU and RAM. The processing unit 51 reads a computer program 54 stored in the storage unit 52 and performs various information processing according to the program 54.

[0068] The storage unit 52 is an auxiliary storage device that includes at least one non-volatile memory (recording medium) from among HDD and SSD. The storage unit 52 may also include flash ROM, USB memory, or SD card. The computer program 54 of the central unit 5 includes a program that causes the CPU of the processing unit 51 to perform remote control (traffic adaptation control) of the second controller 6B.

[0069] When the processing unit 51 generates signal control parameters via remote control, it generates a signal control command to be executed by the second controller 6B, which is the target of remote control. The signal control command is information regarding the timing of the color change of the signal lamp corresponding to the newly generated signal control parameter, and is generated every control cycle of remote control (e.g., 1.0 to 2.5 minutes).

[0070] The communication unit 53 is a communication interface capable of both communication with the information processing device 2 via the public communication network 8 and communication with the second controller 6B via a dedicated communication line 9. The communication unit 53 may also be connected to the information processing device 2 via a dedicated communication line 9.

[0071] The communication unit 53 transmits the signal control commands generated by the processing unit 51 for each control cycle of the signal control parameters to the second controller 6B, which is the target of remote control. The communication unit 53 transmits signal information, including the cycle length and red time length, used by the first and second controllers 6A and 6B, to the information processing device 2. The signal information for the second controller 6B is transmitted to the information processing device 2 every control cycle of remote control (e.g., 1.0 to 2.5 minutes).

[0072] [Definition of pulsation and its causes] Figure 3 is an explanatory diagram showing an example of road links LN1 and LN2 where pulsation may occur. Pulsation is a periodic disturbance in traffic flow that can occur when the cycle length differs at the upstream and downstream intersections of a road link. Pulsation can cause delays and stops in vehicle traffic. The presence or absence of pulsation in road links is useful for determining whether or not to connect sub-areas, as described in Patent Document 1, and is also important information for navigation systems in planning routes and delivery plans, such as avoiding routes where pulsation occurs.

[0073] As shown in Figure 3, we assume a road link LN1 from intersection A to intersection B (hereinafter referred to as the "first link") and a road link LN2 from intersection B to intersection A (hereinafter referred to as the "second link"), and the cycle lengths of each intersection A and B are C1 and C2 (>C1). Here, as an example, we assume C1 = 100 seconds and C2 = 120 seconds. In this case, pulsation may occur in both the first and second links LN1 and LN2 with a period of the least common multiple of the cycle lengths C1 and C2 (= 600 seconds). The reason for this is explained below.

[0074] Figure 4 is a time chart showing the reasons for pulsation in the first link LN1. In Figure 4, the white time slots (in 10-second increments) represent the green time at intersection A, and the time slots with diagonal lines (in 10-second increments) represent the red time at intersection A. As shown in Fig. 4, when the cycle length C1 of the upstream intersection A is smaller than the cycle length C2 of the downstream intersection B (C1 < C2), for the downstream intersection B, the traffic volume for more than one cycle (traffic volume for more than 50 seconds of green) at the upstream intersection A flows in.

[0075] Specifically, the inflow traffic volume to intersection B changes in the order of green for 70 seconds → green for 70 seconds → green for 60 seconds → green for 50 seconds → green for 50 seconds for each cycle length C2 of intersection B. In this case, for example, if the inflow traffic volume that can be processed at intersection B is "green for 60 seconds", a backlog will occur in the first two cycles at intersection B, and the backlog can be resolved after the third cycle. This is the reason for the pulsation generation in the first link LN1.

[0076] Fig. 5 is a time chart showing the reason for the pulsation generation in the second link LN2. In Fig. 5, the white time slots (in 10 - second units) represent the green time of intersection B, and the shaded time slots (in 10 - second units) represent the red time of intersection B. As shown in Fig. 5, when the cycle length C2 of the upstream intersection B is larger than the cycle length C1 of the downstream intersection A (C2 > C1), for the downstream intersection A, the traffic volume for less than one cycle (traffic volume for less than 60 seconds of green) at the upstream intersection B flows in.

[0077] Specifically, the inflow traffic volume to intersection A changes in the order of green for 60 seconds → green for 60 seconds → green for 60 seconds → green for 40 seconds → green for 40 seconds → green for 40 seconds for each cycle length C1 of intersection A. In this case, since C2 > C1, it is considered that the green time of intersection A is less than the green time of intersection B. Therefore, a backlog occurs in the first half of three cycles at the downstream intersection A, and the backlog can be resolved after the fourth cycle. This is the reason for the pulsation generation in the second link LN2.

[0078] 〔Procedure for determining the presence or absence of pulsation using probe information〕 As mentioned above, the method described in Patent Document 1, which determines the signal control parameters for sub-areas necessary for calculating evaluation values ​​that take into account the effects of pulsation from the congestion length and saturation degree based on the detection signals of vehicle detectors, cannot be applied to roads where vehicle detectors are not installed. Furthermore, because vehicle detectors are installed at relatively large intervals from intersections (for example, 200m), it is difficult to accurately grasp traffic indicators that represent the degree of delay in vehicle traffic due to waiting at traffic lights (hereinafter referred to as "delay indicators"), and therefore it is not possible to determine the occurrence of pulsations with much precision.

[0079] Therefore, in this embodiment, probe information that can be collected even without a vehicle detector is used to calculate the delay time dav per vehicle due to waiting at a traffic light, which is one of the delay indicators mentioned above, and the presence or absence of pulsation is determined based on this delay time dav. Specifically, the determination of the presence or absence of pulsation in this embodiment includes the following steps 1 to 3. Step 1: Calculate the average travel time Ttt for the signal waiting section from the probe data (Equation (1)). Step 2: Calculate the delay time per vehicle, dav, from the average travel time Ttt (Equation (2)). Step 3: Determine the presence or absence of pulsation from the periodicity of the peak of the delay time dav (Figure 12)

[0080] As described in steps 1-3, in this embodiment, the travel time calculated from probe information is not the average travel time Tt of the link between intersections, but the average travel time Ttt of the signal waiting section at the downstream intersection that is the target of the determination. Therefore, the following explains the problems of using the average travel time Tt for links and the advantages of using the average travel time Ttt for signal waiting periods.

[0081] [Relationship between travel time between links and delay time due to traffic lights] Figure 6 is a graph showing an example of the travel trajectory when multiple vehicles travel along the road link from intersection J1 to intersection J2. The horizontal axis of the graph represents the distance from intersection J1, and the vertical axis represents travel time. The meanings of the variables included in Figure 6 are as follows:

[0082] dav: Average delay time per vehicle due to waiting at traffic lights (seconds) L: Link length between intersections (m) Tt: Average travel time of the probe vehicle (= link travel time between J1 and J2) (seconds) Ve: Expected speed (e.g., regulated speed) (km / h) J1: Intersection upstream of the target intersection J2: Intersections subject to remote control (single-story intersections)

[0083] When multiple vehicles pass through the link between intersections J1 and J2, the delay time dav per vehicle due to waiting at the traffic light is the total delay time (area of ​​the triangle) of all vehicles passing through intersection J2 after waiting at the traffic light, divided by the number of vehicles. The average travel time Tt of multiple probe vehicles 3 can be considered to include the delay time dav per vehicle mentioned above.

[0084] Therefore, the delay time dav per vehicle due to waiting at traffic lights is the average travel time Tt of multiple probe vehicles 3 minus the travel time (=L / (Ve / 3.6)) if the link were traveled at the assumed speed Ve without waiting at traffic lights. In other words, the delay time dav can be defined by the following equation (0). dav = Tt - {L / (Ve / 3.6)} ……(0) However, the delay time dav, which is calculated using equation (0) based on the average travel time Tt of the link, has the following problems.

[0085] [Problems with using the average travel time of links] Figure 7 is an explanatory diagram illustrating an example of a stop event that affects the accuracy of the delay time dav based on the average travel time Tt of the link. As shown in Figure 7, in addition to waiting at the traffic light at intersection J2, the following events E1 and E2 are possible stopping events that may occur when the probe vehicle 3 travels along the link from intersection J1 to intersection J2. Event E1: Stopping due to becoming the vehicle following bus 3X which had stopped at a bus stop. Event E2: Stopped due to becoming the vehicle following another vehicle (3Y) entering or exiting the parking lot.

[0086] However, in equation (0) above, the average travel time Tt of the link between intersections J1 and J2 is used as the travel time obtained from probe information. Therefore, if the above events E1 and E2 occurred in probe vehicle 3, the average travel time Tt will include the stopping time of events E1 and E2, and the delay time dav based on equation (0) may be greater than the actual time. In this case, the determination of whether or not there is pulsation based on the delay time dav will be inaccurate.

[0087] [Solution using the average travel time during traffic light waiting periods] In this embodiment, in order to address the above-mentioned problems, instead of calculating the "average travel time Tt of the link," which may include the stopping time of events E1 and E2 other than waiting for traffic lights, we calculate the "average travel time Ttt of the traffic light waiting section" at the entrance road to the downstream intersection J2 (see equation (1) below), and use this average travel time Ttt to calculate the delay time dav per vehicle due to waiting for traffic lights at the entrance road to intersection J2 (see equation (2) below).

[0088] The average travel time Ttt for sections where trains are waiting at traffic lights either does not include, or is very unlikely to include, the stopping time for events E1 and E2 other than waiting at traffic lights. Therefore, by adopting the above calculation method, it is possible to accurately calculate the delay time dav per vehicle due to waiting at a traffic light on the on-ramp leading into intersection J2, regardless of the presence or absence of other stopping events such as events E1 and E2.

[0089] Figure 8 is an explanatory diagram showing an example of the definition of variables used to calculate the average travel time Ttt in a signal waiting section. The variables include section i (i=1,2...N), the length of section i Li (m), and the average speed Vi (km / h) of probe vehicle 3 traveling through section i. Section i consists of multiple subsections obtained by dividing the link between intersections J1 and J2 into a predetermined number of divisions N. The length of section i (hereinafter also referred to as "section length") Li is a calculated or set value determined to be sufficiently shorter than the link length L between intersections J1 and J2.

[0090] The processing unit 11 of the information processing device 2 executes the following processes a1 and a2 as preprocessing for the calculation of the delay time dav (see Figure 9). Process a1: The value obtained by dividing the link length L by the number of divisions N (=L / N) is taken as the interval length Li. Process a2: Assign identification numbers (i=1, 2...N) to each section i sequentially, starting from the downstream side of the link and moving upstream. Specifically, the identification number for the downstream section is set to "1," and the identification numbers are incremented towards the upstream side, with the last identification number being "N."

[0091] The processing unit 11 of the information processing device 2 may execute the following processes b1 and b2 as preprocessing for the calculation of the delay time dav (see Figure 9). Process b1: The number of link divisions N is determined by adding 1 to the quotient M obtained by dividing the link length L by a predetermined distance Lo (=M+1), and the remaining distance value is the length LN of the last interval N. Process b2: Assign identification numbers (i=1, 2...N) to interval i sequentially, starting from the downstream side of the link and moving upstream. Specifically, process b2 is the same as process a2.

[0092] In the above preprocessing, if the link between intersections J1 and J2 has branching nodes such as unsignaled intersections, it is preferable to divide section i at the branching nodes. Furthermore, the length Li of each section i (i=1, 2...N) included in the link is not necessarily constant; the length Li of each section included in a single link may be varied, for example, by making the downstream section shorter and the upstream section longer.

[0093] In the above preprocessing, it is preferable that the length (section length) Li of each of the multiple sections i is set to a value smaller than the installation interval (e.g., 200m) of the vehicle sensors that are actually installed on the road to measure vehicle speed. This method allows for finer measurement of the average vehicle speed compared to measuring it using vehicle sensors. Consequently, the signal waiting sections, which are determined according to the total number of sections I, can be calculated more precisely, improving the accuracy of the delay time dav.

[0094] The average speed Vi of probe vehicle 3 in section i (hereinafter also referred to as "section speed") is the average speed of probe vehicle 3 calculated from the position and time of multiple probe data points. The method for calculating the average speed Vi for each section i will be described later.

[0095] [Calculation process for delay time] Figure 9 is a flowchart showing an example of the calculation process for the delay time dav per vehicle due to waiting for a signal, which is performed by the processing unit 11 of the information processing device 2. The calculation process in Figure 9 is performed at predetermined control cycles CL (e.g., 1.0 to 2.5 minutes).

[0096] As shown in Figure 9, the processing unit 11 first extracts probe information from multiple probe vehicles 3 that passed through the link between intersections J1 and J2 during the current control cycle CL, as a data collection process necessary for calculating the delay time dav (step ST10). Specifically, the processing unit 11 extracts probe information whose location is on the link and whose time falls within the current control cycle CL by performing map matching against the probe information contained in the probe database 22.

[0097] Next, the processing unit 11 calculates the average speed Vi of each section i (i=1,2...N) included in the link as the first process for calculating the delay time dav (step ST11). Specifically, the processing unit 11 calculates the travel speed in section i based on the position and time (speed may also be used) of the probe vehicle 3 that passed through the link. Next, the processing unit 11 divides the sum of the travel speeds in section i for multiple probe vehicles 3 by the number of probe vehicles 3 and uses this value as the average speed Vi of section i.

[0098] Next, the processing unit 11 calculates the total number of sections I within the signal waiting section on the inflow road leading to the intersection J2 to be controlled as a second process for calculating the delay time dav (step ST12). The total number of sections I corresponds to the identification number of section i located at the uppermost part of the signal waiting section on the access road leading to the controlled intersection J2. Details of the calculation process for the total number of sections I (see Figure 10) will be described later.

[0099] Next, as a third process for calculating the delay time dav, the processing unit 11 calculates the average travel time Ttt for the signal waiting section using the total number of sections I mentioned above (step ST13). Specifically, the processing unit 11 calculates the average travel time Ttt using the following equation (1). As shown in equation (1), the average travel time Ttt in the signal waiting section is the sum of the average travel times (=Li / (Vi / 3.6)) of probe vehicle 3 for each section i from section 1 to the total number of sections I.

[0100]

number

[0101] Finally, as a fourth process for calculating the delay time dav, the processing unit 11 uses the total number of sections I and the average travel time Ttt to calculate the delay time dav per vehicle due to waiting at signals in the signal waiting section (step ST14). Specifically, the processing unit 11 calculates the delay time dav using the following equation (2). As shown in equation (2), the delay time dav in the signal waiting section is the time obtained by subtracting the travel time (=Σ(Li / (Ve / 3.6)) that would occur if the signal waiting section (section 1 to section I) were traveled at the assumed speed Ve without any signal waiting from the average travel time Ttt in the signal waiting section.

[0102]

number

[0103] In the calculation process for the delay time dav shown in Figure 9, the third process in step ST13 and the fourth process in step 14 may be executed using a single mathematical formula, which is formed by substituting equation (1) into Ttt on the right-hand side of equation (2).

[0104] [Calculation process for the total number of sections within the signal waiting area] Figure 10 is a flowchart showing an example of the calculation process for the total number of sections I within the signal waiting section, which is performed by the processing unit 11 of the information processing device 2. In Figure 10, "ML" is a variable representing the section length at which the section velocity Vi exceeds the velocity threshold TS. "TS" is the velocity threshold, and "TL" is the distance threshold.

[0105] The speed threshold TS is an estimated average speed of a vehicle when it stops at a traffic light before intersection J2. The speed threshold TS is a set value determined according to factors such as the length of the section Li, and here it is assumed to be TS = 25 km / h. The distance threshold TL is an estimated distance traveled by a vehicle traveling at an average speed exceeding the speed threshold TS, if it continues to travel between intersections J1 and J2 without stopping. The distance threshold TL is a set value determined according to factors such as the magnitude of the speed threshold TS, and here it is assumed to be TL = 100m.

[0106] As shown in Figure 10, the processing unit 11 of the information processing device 2 first performs initial variable settings (step ST20). Specifically, the processing unit 11 sets the initial values ​​of the total number of intervals I, the interval length ML, and the interval i to I=0, ML=0, and i=1, respectively.

[0107] Next, the processing unit 11 determines whether Vi ≤ TS is true (step ST21). If the result of step ST21 is positive (the section speed Vi of section i being judged is less than or equal to the speed threshold TS), the processing unit 11 sets I=i (step ST22) and then increments section i (step ST23).

[0108] Next, the processing unit 11 determines whether i ≥ N is true (step ST24). If the result of the determination in step ST24 is positive, the processing unit 11 terminates the process. If the result of the determination in step ST24 is negative, the processing unit 11 returns to the state before step ST21. A loop including steps ST21 to ST24 searches for sections i that satisfy the speed condition where the section speed Vi is less than or equal to the speed threshold TS, starting from the downstream side of the inflow road. A search process is then performed in which sections that satisfy the speed condition are counted as sections i included in the signal waiting section.

[0109] If the result of step ST21 is negative (i.e., the section velocity Vi of section i being evaluated exceeds the velocity threshold TS), the processing unit 11 adds the section length Li of section i being evaluated to the variable ML (step ST25), and then determines whether ML ≥ TL is true (step ST26).

[0110] If the result of step ST26 is negative (i.e., the variable ML is less than the distance threshold TL), the processing unit 11 resets the variable ML to 0 (step ST27), provided that Vi+1 ≤ TS is true, and returns the process to before step ST23. Note that "i+1" in section velocity Vi+1 is an index of velocity V. Therefore, if Vi+1 > TS, the value of the variable ML is not reset and is maintained, and the process returns to before step ST23.

[0111] The reason for resetting the variable ML to 0 when Vi+1≦TS holds is that if the interval velocity Vi+1 in the next interval i+1 is less than or equal to the velocity threshold TS, it is clear that the variable ML will not increase in the next interval i+1. If the result of step ST26 is positive (variable ML is greater than or equal to the distance threshold TL), the processing unit 11 determines the number value of the last section i that satisfies Vi ≤ TS as the total number of sections I within the signal waiting section (step ST28), and terminates the process.

[0112] [Example of calculating the total number of sections within a signal waiting zone] Figure 11 is an explanatory diagram showing an actual example of the calculation of the total number of intervals I. In Figure 11, the values ​​"u1" to "u5" are the measured values ​​of the section speed Vi obtained from probe information of multiple probe vehicles 3, and are assumed to be the following values. Also, the number of link divisions N is 15, the section length Li of each section i is 50m, the TS is 25km / h, and the TL is 100m.

[0113] u1 = a value for speeds of 10 km / h or less u2 = value for speeds of 15 km / h or less u3 = a value for speeds of 20 km / h or less u4 = value for speeds below 25 km / h u5 = a value exceeding 25 km / h

[0114] As shown in Figure 11, the section speeds V1 and V2 (=u1) are below the speed threshold TS, and the section speeds V3 and V4 (=u3) are also below the speed threshold TS. Therefore, the loop of steps ST21 to ST24 in Figure 10 counts up to "4". Since the section speed V5 (=u5) exceeds the speed threshold TS (No in step ST21 of Figure 10), the loop from steps ST21 to ST24 in Figure 10 is exited, and the variable ML becomes L5 (step ST25 of Figure 10).

[0115] Since the value of variable ML (L5=50m) is less than the distance threshold TL (=100m), and the interval velocity V6 (=u4) of the next interval 6 is less than the velocity threshold TS (No in step ST26 in Figure 10), ML is reset to 0 and the search for the total number of intervals I continues (step ST27 in Figure 10). Therefore, the total number of intervals I is counted up to "5".

[0116] The section speeds V6 and V7 (=u4) are below the speed threshold TS. Therefore, the total number of sections I is counted up to "7" by the loop of steps ST21 to ST24 in Figure 10. Since the section speed V8 (=u5) exceeds the speed threshold TS (No in step ST21 of Figure 10), the loop from steps ST21 to ST24 in Figure 10 is exited, and the variable ML becomes L8 (step ST25 of Figure 10).

[0117] The value of variable ML (L8=50m) is less than the distance threshold TL (=100m), and the interval velocity V9 (=u5) of the next interval 9 is greater than or equal to the velocity threshold TS (No in step ST26 of Figure 10). Therefore, the search for the total number of intervals I continues while maintaining ML=L8 (step ST27 of Figure 10). Consequently, the total number of intervals I is counted up to "8".

[0118] Since the section speed V9 (=u5) exceeds the speed threshold TS (No in step ST21 of Figure 10), the loop from steps ST21 to ST24 in Figure 10 is exited, and the variable ML = L8 + L9 (step ST25 of Figure 10).

[0119] Since the value of variable ML (L8 + L9 = 100m) is greater than or equal to the distance threshold TL (= 100m) (Yes in step ST26 in Figure 10), the last interval i (= 7) that satisfies Vi ≤ TS is determined as the value of the total number of intervals I (step ST28 in Figure 10), and the process ends. In this case, the uppermost point of the last section i (=7) is considered the end of the signal waiting section. Therefore, the speed Vi and section length Li of sections 8-15 upstream of section 7 are excluded from the data used to calculate the average travel time Ttt.

[0120] [Process for determining the presence or absence of pulsation] Figure 12 is a flowchart showing an example of a process for determining the presence or absence of pulsation, which is performed with the delay time (DAV) as the target. As shown in Figure 12, the processing unit 11 of the information processing device 2 first collects the calculation result of the delay time dav due to signal waiting included in a predetermined period (step ST30). The predetermined period mentioned above is set to be a period that is sufficiently longer than, for example, the pulsation generation period (the least common multiple of cycles C1 and C2 at intersections A and B in Figure 3) (e.g., 1 hour or more).

[0121] Next, the processing unit 11 arranges the calculation results of the delay time dav in the order of the control period CL to generate time-series data of the delay time dav (step ST31). A specific example of the time-series data of the delay time dav will be described later. Next, the processing unit 11 determines whether or not there is a periodic occurrence of peaks in the generated delay time dav in the time series data (step ST32). A specific example of this determination method will be described later.

[0122] If the result of step ST32 is positive, the processing unit 11 determines that pulsation has occurred in the road link being judged (step ST33). If the result of step ST32 is negative, the processing unit 11 determines that no pulsation has occurred for the road link being evaluated (step ST34).

[0123] Figure 13 is a graph showing an example of time-series data of the delay time dav. In Figure 13, the time-series data for a predetermined period of 5 hours from 5:00 AM to 10:00 AM is shown as an example. The time threshold TH1 in Figure 13 is pre-set in the storage unit 12. The processing unit 11 of the information processing device 2 performs a determination (step ST32 in Figure 12) based on the time-series data of the delay time dav shown in Figure 13, for example, to determine whether or not a peak in the delay time dav occurred periodically.

[0124] Specifically, the processing unit 11 first identifies a period P1 in which the delay time dav is equal to or greater than a predetermined time threshold TH1, and extracts the times corresponding to multiple peaks of the delay time dav included in that period P1 (hereinafter referred to as "corresponding times"). In the example diagram, period P1 contains six peaks, and the corresponding times for each peak are the following times t1 to t6. Therefore, in this case, the processing unit 11 extracts these six times t1 to t6 as the corresponding times.

[0125] Time t1:AM7:00 Time t2:AM7:10 Time t3:AM7:20 Time t4:AM7:30 Time t5:AM7:40 Time t6:AM7:50

[0126] Next, the processing unit 11 calculates the time difference between adjacent corresponding times (for example, t1 and t2) among the extracted multiple corresponding times t1 to t6 using the following formula, and calculates the rate of change of said time difference. Time difference Δt21=t2-t1(=10 minutes) Time difference Δt32=t3-t2(=10 minutes) Time difference Δt43=t4-t3(=10 minutes) Time difference Δt54=t5-t4(=10 minutes) Time difference Δt65=t6-t5(=10 minutes)

[0127] Next, the processing unit 11 determines whether or not the peak is periodic based on the calculated rate of change of the time difference Δt21 to Δt65. Specifically, the processing unit 11 determines that the peak is periodic if the rate of change of the time difference Δt21 to Δt65 is less than or equal to a predetermined value (for example, 10%), and determines that the peak is not periodic if it exceeds the predetermined value. In the example figure, the time differences Δt21 to Δt65 are all the same value (=10 minutes), and the rate of change is zero, so it is determined that this is a periodic occurrence of the peak in the delay time dav.

[0128] The time threshold TH1 is set, for example, to a time value for waiting for a signal to identify whether the inflow path to be determined is in a saturated state or an unsaturated state. That is, the time threshold TH1 is a time value of the delay time such that when dav ≧ TH1, it can be estimated that the inflow path is saturated, and when dav < TH1, it can be estimated that the inflow path is unsaturated. The reason is that when the delay time dav is less than the time threshold TH1, it is an unsaturated state where there is no remaining traffic at the end of the green time. Therefore, even if the delay time dav changes within the range less than the time threshold TH1, it cannot be said to be a pulsation that promotes vehicle delay and stop.

[0129] For example, if the red time of the inflow path to be determined is R, the time threshold TH1 may be set to (R / 2) ± σ. Note that σ is an adjustment value that can be changed as needed.

[0130] 〔Modification example of determination process of presence or absence of pulsation〕 In the above embodiment, the delay time dav per vehicle due to signal waiting is adopted as the delay index used for determining the presence or absence of pulsation. However, for example, the "queue length Qu" in the inflow path of the intersection may be adopted as the delay index.

[0131] FIG. 14 is a flowchart showing another example of the determination process of the presence or absence of pulsation, which is executed by monitoring the queue length Qu. As shown in FIG. 14, the processing unit 11 of the information processing apparatus 2 first collects the calculation result of the queue length Qu due to signal waiting included in a predetermined period (step ST40). The above-mentioned predetermined period is set to a period sufficiently longer than, for example, the pulsation generation cycle (the least common multiple of the cycles C1 and C2 of intersections A and B in FIG. 3) (for example, 1 hour or more).

[0132] The above-mentioned queue length Qu is calculated based on the total number of intervals I within the signal waiting interval, which is the calculation result of step ST12 (calculation process in FIG. 10) in FIG. 9. Specifically, the processing unit 11 calculates the queue length Qu due to signal waiting using equation (3), which sums the lengths Li of the intervals i (i=1,2…) up to the total number of intervals I. This is because the total number of intervals I is an identification number that can be considered as the uppermost (end) end of the signal waiting section. Note that "Li" in equation (3) has the same meaning as the length of interval i in Figure 9.

[0133]

number

[0134] Next, the processing unit 11 arranges the calculation results of the queue length Qu in the order of the control period CL to generate time-series data of the queue length Qu (step ST41). A specific example of the time-series data of the queue length Qu will be described later. Next, the processing unit 11 determines whether or not there is a periodic occurrence of peaks in the queue length Qu in the time-series data of the generated queue length Qu (step ST42). Details of this determination method will be described later.

[0135] If the result of step ST42 is positive, the processing unit 11 determines that pulsation has occurred in the road link being judged (step ST43). If the result of step ST42 is negative, the processing unit 11 determines that no pulsation has occurred for the road link being evaluated (step ST44).

[0136] Figure 15 is a graph showing an example of time-series data for queue length Qu. In Figure 15, time-series data is shown as an example when the predetermined period is 5 hours, from 5:00 AM to 10:00 AM. The distance threshold TH2 in Figure 15 is pre-set in the storage unit 12. The processing unit 11 of the information processing device 2 performs a determination (step ST42 in Figure 14) to determine whether or not a peak in the queue length Qu occurred periodically, based on the time-series data of the queue length Qu shown in Figure 15, for example.

[0137] Specifically, the processing unit 11 first identifies a period P2 in which the queue length Qu is equal to or greater than a predetermined threshold TH2, and extracts the times corresponding to multiple peaks of the queue length Qu included in that period P2 (hereinafter referred to as "corresponding times"). In the example diagram, period P2 contains six peaks, and the corresponding times for each peak are the following times u1 to u6. Therefore, in this case, the processing unit 11 extracts these six times u1 to u6 as the corresponding times.

[0138] Time u1:AM7:00 Time u2:AM7:10 Time u3:AM7:20 Time u4:AM7:30 Time u5:AM7:40 Time u6:AM7:50

[0139] Next, the processing unit 11 calculates the time difference between adjacent corresponding times (for example, u1 and u2) among the extracted multiple corresponding times u1 to u6 using the following formula, and calculates the rate of change of said time difference. Time difference Δu21=u2-u1(=10 minutes) Time difference Δu32=u3-u2(=10 minutes) Time difference Δu43=u4-u3(=10 minutes) Time difference Δu54=u5-u4(=10 minutes) Time difference Δu65=u6-u5(=10 minutes)

[0140] Next, the processing unit 11 determines whether or not the peak is periodic based on the calculated rate of change of the time difference Δu21 to Δu65. Specifically, the processing unit 11 determines that the peak is periodic if the rate of change of the time difference Δu21 to Δu65 is less than or equal to a predetermined value (for example, 10%), and determines that the peak is not periodic if it exceeds the predetermined value. In the example diagram, the time differences Δu21 to Δu65 are all the same value (=10 minutes), and the rate of change is zero, so it is determined that this is a periodic occurrence of the peak in the queue length Qu.

[0141] The distance threshold TH2 is set, for example, to the distance value for signal waiting to identify whether the inflow path to be determined is in a saturated state or an unsaturated state. That is, the distance threshold TH2 is the distance value of the queue length such that when Qu≥TH2, it can be estimated that the inflow path is saturated, and when Qu<TH2, it can be estimated that the inflow path is unsaturated. The reason is that when the queue length Qu is less than the distance threshold TH2, it is an unsaturated state where there is no backlog at the end of the green time. Therefore, even if the queue length Qu changes within the range less than the distance threshold TH2, it cannot be said that it promotes the pulsation that causes vehicle passage delays and stops.

[0142] The distance threshold TH2 may be set, for example, to the queue length (hereinafter referred to as the "maximum queue length") corresponding to the maximum number of vehicles that can be processed in one green time on the inflow path to be determined. Note that the time threshold TH2 may be a fixed value (for example, 250 m), or may be variably set in the form of X% with respect to the link length.

[0143] [Other Variants] The above-described embodiments (including variants) are illustrative in all respects and not restrictive. The scope of the rights of the present invention includes all modifications within the scope equivalent to the configurations described in the claims.

[0144] For example, in the above-described embodiment, when the central device 5 can collect and analyze probe information, the central device 5 may determine the presence or absence of pulsation in the inflow path of the intersection using the probe information collected by itself. That is, the determination process of the presence or absence of pulsation by the processing unit 11 of the information processing device 2 described above may be executed by the processing unit 51 of the central device 5. [Explanation of Reference Numerals]

[0145] 1 Traffic signal control system 2 Information processing device 3 Probe vehicle (vehicle) 3X Bus 3Y Other vehicles 4 Vehicle-mounted device 5. Central System (Information Processing System) 6. Traffic signal controller 6A First Controller 6B Second controller 7 Wireless base stations 8. Public telecommunications network 9. Communication lines 10 server computers 11. Information Processing Department 12 Storage section 13 Communications Department 14 Computer Programs 21 Map Database 22 Probe Database 23 Member Database 24 Signal Information Database 25 Road map data 31 Processing Unit 32 Storage section 33 Communications Department 34 Computer Programs 51 Processing Unit 52 Storage section 53 Communications Department 54 Computer Programs

Claims

1. A storage unit that stores probe information of probe vehicles traveling on the road leading into the intersection, The system includes an information processing unit that performs a process to determine whether or not there is pulsation in the inflow passage, The aforementioned determination process is: A process to generate time-series data of a delay index, which is a traffic index representing the degree of delay in vehicle traffic due to waiting at traffic lights, calculated from the aforementioned probe information, An information processing device including a process for determining the presence or absence of pulsation based on time-series data of the delay index.

2. The aforementioned delay index is, The information processing device according to claim 1, which is the delay time per vehicle due to waiting at a traffic light, calculated from the average travel time in the traffic light waiting section of the aforementioned access road.

3. The average travel time for the aforementioned signal waiting section is, The information processing apparatus according to claim 2, calculated by the following formula (1). [Math 1] However, Ttt: Average travel time (seconds) in the section where traffic lights are stopped. Li: Length of section i (m) Vi: Average speed of section i (km / h) I: Total number of sections within the signal waiting zone i: Identification number of the section assigned sequentially from the downstream side.

4. The aforementioned delay index is, The information processing apparatus according to claim 3, calculated by the following formula (2). [Math 2] However, dav: average delay time per vehicle due to waiting at traffic lights (seconds) Ve: Expected speed (e.g., regulated speed) (km / h)

5. The aforementioned storage unit is The system stores a signal waiting time threshold for identifying whether the inflow channel is saturated or unsaturated. The aforementioned information processing unit, The information processing apparatus according to any one of claims 2 to 4, wherein the periodic occurrence of the peak of the delay time, which is above the time threshold, is determined to be the pulsation.

6. The aforementioned delay index is, The information processing device according to claim 1, wherein the queue length due to waiting for a signal in the aforementioned inflow path is the queue length due to waiting for a signal.

7. The aforementioned queue length is, The information processing apparatus according to claim 6, calculated by the following formula (3). [Math 3] However, Qu: queue length due to traffic light delay (m) Li: Length of section i (m) I: Total number of sections within the signal waiting zone i: Identification number of the section assigned sequentially from the downstream side.

8. The aforementioned storage unit is The system stores a distance threshold for signal waiting to identify whether the inflow path is saturated or unsaturated. The aforementioned information processing unit, The information processing apparatus according to claim 6 or claim 7, wherein the periodic occurrence of a peak in the queue length that is greater than or equal to the distance threshold is determined to be the pulsation.

9. An information processing method performed by an information processing device, A step of storing probe information of a probe vehicle traveling on an access road to an intersection, The step includes performing a process to determine whether or not there is pulsation in the inflow passage, The aforementioned determination process is: A process to generate time-series data of a delay index, which is a traffic index representing the degree of delay in vehicle traffic due to waiting at traffic lights, calculated from the aforementioned probe information, An information processing method including a process for determining the presence or absence of pulsation based on time-series data of the delay index.

10. A storage unit for storing probe information of probe vehicles traveling on an on-ramp to an intersection, and A computer program for causing a computer to function as an information processing unit that performs a process to determine whether or not there is pulsation in the inflow channel, The aforementioned determination process is: A process to generate time-series data of a delay index, which is a traffic index representing the degree of delay in vehicle traffic due to waiting at traffic lights, calculated from the aforementioned probe information, A computer program that includes a process for determining the presence or absence of pulsation based on time-series data of the delay index.

Images