Information processing device, information processing method, and computer program

Abstract

To improve the accuracy of calculating the delay time per vehicle due to waiting at a traffic light.SOLUTION: A device according to an aspect of the present disclosure includes: an acquisition unit for acquiring probe information of a probe vehicle passing on an incoming route to an intersection; and an information processing unit that uses the probe information as source data to perform a calculation process of a delay time per vehicle due to waiting for a signal on the incoming route. The calculation process includes: a first process for calculating, based on the probe information, a plurality of section speeds, which are average speeds of vehicles for each section of the incoming route divided into a plurality of sections; a second process for calculating, based on the plurality of section speeds, the total number of sections, which is the total number of sections included in the signal waiting sections on the incoming route; a third process for calculating the average travel time of the signal waiting sections based on the total number of sections; and a fourth process for calculating the delay time based on the total number of sections and the average travel time of the signal waiting sections.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present disclosure relates to Information processing device, information processing method , and a computer program. This application claims priority based on Japanese Patent Application No. 2020-175372 filed on October 19, 2020, and incorporates by reference all the descriptions described in the above Japanese application.

Background Art

[0002] Patent Document 1 describes a traffic index calculation device including: a first calculation unit that calculates normalized data representing traffic variables of an inflow road of a target intersection as a ratio to a saturated traffic flow rate; and a second calculation unit that calculates a traffic index defined by an equation in which the traffic variables of the inflow road are included in the numerator and the saturated traffic flow rate is included in the denominator using the calculated normalized data.

[0003] In the calculation device of Patent Document 1, the delay time per vehicle due to signal waiting in the inflow road is calculated from the average travel time of the probe vehicle, and the above-described normalized data is calculated based on the calculated delay time.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] An apparatus according to one aspect of the present disclosure includes: an acquisition unit that acquires probe information of a probe vehicle traveling on an access road to an intersection; and an information processing unit that uses the probe information as raw data to perform a calculation process for the delay time per vehicle due to waiting at a traffic light on the access road, wherein the calculation process includes: a first process that calculates a plurality of section speeds, which are the average speeds of vehicles for a plurality of sections formed by dividing the access road, based on the probe information; a second process that calculates a total number of sections, which is the total number of sections included in the traffic light waiting section on the access road, based on the plurality of section speeds; a third process that calculates the average travel time of the traffic light waiting section, based on the total number of sections; and a fourth process that calculates the delay time, based on the total number of sections and the average travel time of the traffic light waiting section.

[0006] A method according to one aspect of the present disclosure includes the steps of: acquiring probe information of a probe vehicle traveling on an access road to an intersection; and using the probe information as raw data, performing a calculation process for the delay time per vehicle due to waiting at a traffic light on the access road, wherein the calculation process includes: a first process of calculating a plurality of section speeds, which are the average speeds of vehicles for a plurality of sections formed by dividing the access road, based on the probe information; a second process of calculating a total number of sections, which is the total number of sections included in the traffic light waiting section on the access road, based on the plurality of section speeds; a third process of calculating the average travel time of the traffic light waiting section, based on the total number of sections; and a fourth process of calculating the delay time, based on the total number of sections and the average travel time of the traffic light waiting section.

[0007] A computer program according to one aspect of the present disclosure is a computer program for causing a computer to function as an acquisition unit that acquires probe information of probe vehicles traveling on an inflow road to an intersection, and an information processing unit that uses the probe information as raw data to perform a calculation process for the delay time per vehicle due to waiting at a traffic light on the inflow road, wherein the calculation process includes: a first process that calculates a plurality of section speeds, which are the average speeds of vehicles for a plurality of sections formed by dividing the inflow road, based on the probe information; a second process that calculates a total number of sections, which is the total number of sections included in the traffic light waiting section on the inflow road, based on the plurality of section speeds; a third process that calculates the average travel time of the traffic light waiting section, based on the total number of sections; and a fourth process that calculates the delay time, based on the total number of sections and the average travel time of the traffic light waiting section. [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 a flowchart showing an overview of remote control in a comparative example. [Figure 4] Figure 4 is a flowchart illustrating the overview of remote control in this embodiment. [Figure 5] Figure 5 is an explanatory diagram illustrating an example of a method for calculating normalized data when the target intersection for remote control is a single intersection. [Figure 6] Figure 6 is an explanatory diagram showing the traffic conditions at an intersection when it is not saturated, and the relationship necessary for deriving the traffic volume Vin normalized by Sf. [Figure 7] Figure 7 is an explanatory diagram illustrating an example of traffic conditions at an intersection during a period of oversaturation. [Figure 8] Figure 8 is an explanatory diagram illustrating an example of a stopping event that affects the accuracy of the delay time per vehicle due to waiting at a traffic light. [Figure 9]Figure 9 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 stopped. [Figure 10] Figure 10 is a flowchart showing an example of the process for calculating the delay time per vehicle due to waiting at a traffic light. [Figure 11] Figure 11 is a flowchart showing an example of the process for calculating the total number of sections within a signal waiting zone. [Figure 12] Figure 12 is an explanatory diagram showing an actual example of calculating the total number of intervals. [Figure 13] Figure 13 is an explanatory diagram illustrating an example of a method for calculating delay time when the link between intersections has multiple lanes. [Figure 14] Figure 14 is an explanatory diagram illustrating an example of a method for calculating delay time when the link between intersections has multiple lanes. [Modes for carrying out the invention]

[0009] <Issues this disclosure aims to address> Conventional calculation devices use the link travel time from the upstream intersection to the target intersection as the average travel time of the probe vehicle. Therefore, if the probe vehicle experiences stopping events other than waiting at traffic lights, the delay time may be overestimated. This disclosure aims to improve the accuracy of calculating the delay time per vehicle due to waiting at traffic lights, in light of the aforementioned conventional problems.

[0010] <Effects of this disclosure> According to this disclosure, the accuracy of calculating the delay time per vehicle due to waiting at traffic lights can be improved.

[0011] <Summary of Embodiments of the Invention> The embodiments of the present invention are outlined below. (1) The calculation device of this embodiment includes an acquisition unit that acquires probe information of probe vehicles passing through the inflow roads to an intersection, and an information processing unit that executes a calculation process of the delay time per vehicle due to signal waiting in the inflow roads using the probe information as raw data. The calculation process includes a first process of calculating a plurality of section speeds, which are the average speeds of vehicles for each of a plurality of sections formed by dividing the inflow road based on the probe information, a second process of calculating the total number of sections included in the signal waiting section in the inflow road based on the plurality of section speeds, a third process of calculating the average travel time of the signal waiting section based on the total number of sections, and a fourth process of calculating the delay time based on the total number of sections and the average travel time of the signal waiting section.

[0012] According to the calculation device of this embodiment, the average travel time of the signal waiting section is calculated based on the total number of sections included in the signal waiting section in the inflow road, and the above-mentioned delay time is calculated based on the total number of sections and the average travel time of the signal waiting section. Therefore, regardless of the presence or absence of stop events other than signal waiting, the delay time per vehicle due to signal waiting in the inflow road can be accurately calculated.

[0013] (2) In the calculation device of this embodiment, in the second process, sections that satisfy the speed condition that the section speed is less than or equal to the speed threshold may be searched in order from the downstream side of the inflow road, and a search process of counting the sections that satisfy the speed condition as the sections included in the signal waiting section may be included. The reason is that the sections that satisfy the above speed condition are presumed to be the sections where the speed of the probe vehicle has decreased or stopped due to signal waiting.

[0014] (3) In the calculation device of this embodiment, the second process may include a process of continuing the search process when the length obtained by adding the lengths of each of one or more sections that do not satisfy the speed condition is less than the distance threshold. This is because when the length of the section that does not satisfy the speed condition is short, it is considered that the probe vehicle repeatedly stops and moves within the signal waiting section, and it cannot be said that the section being searched has necessarily reached upstream of the signal waiting section.

[0015] (4) In the calculation device of the present embodiment, the second process may include a process of setting the count value up to the most upstream section that satisfies the speed condition as the total number of sections when the length obtained by adding the respective section lengths of one or more sections whose section speed exceeds the speed threshold is equal to or greater than the distance threshold. This is because when the length of the section that does not satisfy the speed condition is long, it is considered that the section being searched has reached upstream of the signal waiting section, and the most upstream section that satisfies the speed condition in the previous search can be estimated as the end of the signal waiting section.

[0016] (5) In the calculation device of the present embodiment, the respective section lengths of the plurality of sections may be values smaller than the installation interval of the vehicle sensors (for example, 200 m) for measuring the vehicle speed. In this way, compared with the case of measuring the average speed of the vehicle by the vehicle sensor, the measurement granularity of the average speed of the vehicle becomes finer. Therefore, the signal waiting section determined according to the total number of sections can be calculated more finely, and the calculation accuracy of the delay time can be improved.

[0017] (6) In the calculation device of the present embodiment, the third process may be a process of calculating the average travel time of the signal waiting section by the following formula (16). In this case, the average travel time of the signal waiting section can be accurately calculated by the following formula (16).

[0018]

Equation

[0019] (7) In the calculation device of this embodiment, the fourth process may be a process for calculating the delay time by the following formula (17). In this case, the delay time per vehicle due to waiting at a signal can be accurately calculated by the following formula (17).

[0020]

number

[0021] (8) In the calculation device of this embodiment, if the access road is an access road in which the right of way for multiple lanes is defined with the same indication, the information processing unit may perform the second process for each of the multiple lanes, and may perform the third and fourth processes based on the largest total number of sections among the total number of sections calculated by the second process. In this case, among multiple lanes processed under the same signal indication, the delay time for the lane with the greatest degree of remaining congestion is calculated. Therefore, it is possible to accurately calculate intersection traffic indicators that reflect actual traffic conditions, thereby improving the accuracy of signal control parameter calculations.

[0022] (9) The calculation method of this embodiment is the calculation method performed by the calculation devices described in (1) to (8) above. Therefore, the calculation method of this embodiment has the same effects as the calculation devices described in (1) to (8) above.

[0023] (10) The computer program of this embodiment is a computer program that causes the computer to function as the calculation device described in (1) to (8) above. Therefore, the computer program of this embodiment has the same effects as the calculation devices described in (1) to (8) above.

[0024] <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.

[0025] [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 considered vehicles. In this embodiment, the term "vehicle" includes both probe vehicles having an on-board device capable of transmitting probe information and ordinary vehicles that do not have such an on-board device.

[0026] "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 can include various types of vehicle data such as the probe vehicle's identification information, vehicle position, vehicle speed, vehicle direction, and the time of these occurrences. Probe information may also utilize information such as position and acceleration acquired by a smartphone or tablet inside the vehicle.

[0027] "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 vehicles. However, even ordinary vehicles that do not have on-board devices capable of transmitting probe information are included as probe vehicles if they have a smartphone, tablet PC, or similar device that can transmit probe information such as the vehicle's location information externally.

[0028] "Signal control parameters": The cycle length, split, and offset, which are temporal elements of signal representation, are collectively referred to as signal control parameters or signal control constants. "Cycle length" 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, the green color of a traffic signal light is legally referred to as "blue."

[0029] "Signal indication": This refers to the signal indication that shows the relationship between the display status of each light in a traffic signal. The indication indicates the right of passage granted to vehicles and pedestrians at an intersection for each entry lane, and the time period during which that right of passage is granted. "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.

[0030] "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.

[0031] 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, for calculation formulas that include R (for example, formulas (10) and (11) described later), (CG) may be used instead of R. In other words, the red time R in this embodiment may be a value indirectly calculated from the cycle length C and the blue time G.

[0032] "Queue": This refers to a line of vehicles stopped before an intersection, such as waiting at a red light. "Link": This refers to a section of road that connects nodes such as intersections and has an uphill or downhill direction. 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.

[0033] "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.

[0034] "Traffic capacity": Road traffic capacity refers to the maximum number of vehicles that can comfortably pass through a designated section of a road or single lane in one direction within a certain period of time, under road conditions such as road shape, width, and gradient, as well as traffic conditions such as vehicle type composition and speed limits. However, for two-lane or three-lane roads, both traffic capacities are used.

[0035] "Traffic volume" refers to the number of vehicles passing through a given time unit. Unless otherwise specified, it is expressed as the number of vehicles passing through per hour, but for control and evaluation purposes, shorter time units such as seconds, 5 minutes, or 15 minutes may be used. Generally, traffic volume increases in accordance with traffic demand, but conversely, it decreases when traffic demand exceeds traffic capacity.

[0036] "Load Factor": In a supersaturated state, it is necessary to consider the "load traffic volume," which is the sum of the traffic volume passing through the stop line and the number of vehicles remaining in the queue, as the variable to be controlled. The load factor is the ratio of the load traffic volume (traffic flow rate) per unit time to the saturated traffic flow rate. When the number of vehicles unable to pass through due to oversaturation is small, the load factor is equivalent to the demand factor. "Traffic demand": For each intersection or entrance road, or for each direction of traffic, traffic demand refers to the volume of traffic or traffic flow rate that arrives at the stop line of an entrance road within a certain period of time.

[0037] "Traffic flow rate": The traffic flow rate is a value obtained by converting the number of vehicles passing through a certain section of a lane or roadway in a certain amount of time (usually less than one hour) to a value per unit time (usually one hour). For example, if the traffic volume over a 15-minute period is 90 vehicles, the traffic flow rate for that 15-minute period would be 360 ​​vehicles per hour or 6 vehicles per minute. The traffic flow rate is the reciprocal of the average head time of vehicles that passed through during a given period.

[0038] "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.

[0039] "Saturated traffic flow rate": The saturated traffic flow rate is the maximum number of vehicles that can pass through a stop line per lane in a unit of time (e.g., 1 second) at the entrance of an intersection, under conditions of sufficient traffic demand. The saturated traffic flow rate will differ if the traffic flow path is different, such as when there are dedicated right-turn or left-turn lanes in addition to the straight-ahead lane. The saturated traffic flow rate also differs depending on road and traffic conditions, such as lane width and the proportion of large vehicles.

[0040] "Point-based control": When classifying traffic signal control based on the number of intersections and spatial configuration, it can be divided into three types: point-based control, system control, and area control. Of these, point-based control refers to a method of controlling signalized intersections individually.

[0041] "System control" refers to a method of controlling a series of adjacent intersections in a coordinated manner. A key feature of this method is that a common cycle length (common cycle length of the system) and offset are defined for the multiple signals being system controlled. "Area control": This is a system for controlling a large number of traffic signals installed in a road network that spreads across an area. It is an extension of route-based control, but on a more area-based scale.

[0042] "Fixed-period control": When classifying traffic signal control based on the method of setting signal control parameters, it can be divided into three types: fixed-period control, traffic-sensitive control, and traffic-adaptive control. Of these, fixed-period control is a method in which signal control parameters are set in advance according to the time of day. One combination of signal control parameters (called a program) is selected and implemented from the pre-set combinations of signal control parameters according to the time of day and day of the week (weekdays, Saturdays, Sundays, and holidays).

[0043] "Traffic-sensitive control": A method of traffic signal control that uses vehicle sensors and is implemented for each signal controller. Also known as terminal-sensitive control. In traffic-sensitive control, the start and end points of the blue light display are determined in response to short-term changes in traffic demand, and as a result, the length of the blue light display and the cycle length are changed.

[0044] "Traffic Adaptation Control": This is a control method in which a central unit of a traffic control center changes signal control parameters for traffic signal controllers at important intersections, or for traffic signal controllers at multiple intersections that are controlled by a system or area. In this embodiment, it is also called "remote control" because the central unit remotely controls one or more traffic signal controllers. Traffic adaptation control enables advanced system control that responds to fluctuations in traffic flow, making it suitable for roads where traffic volume and its temporal fluctuations are significant and high traffic handling efficiency is required.

[0045] Traffic adaptation control is classified into two types: "program selection control" and "program formation control." Program selection control is a method that selects the most suitable combination (program) from several pre-prepared combinations based on information from vehicle sensors and other sources, which is appropriate for the current traffic conditions. Program-based control is a method that does not require preparing a finite number of signal control parameter combinations, but instead instantly determines the timing of switching signal control parameters or signal light colors based on information from vehicle sensors, etc.

[0046] "MODERATO" (Management by Origin-Destination Related Adaptation for Traffic Optimization): This is the name of the program-based control used in Japan's UTMS (Universal Traffic Management System). MODERATO is a system that automatically generates signal control parameters from the load factor (= (inflow traffic volume + number of vehicles in queue) / saturation traffic flow rate) for each entry lane at an intersection.

[0047] "SCOOT" (Split Cycle Offset Optimisation Technique): A program-based control method developed in the UK. It is widely adopted, especially in European countries. SCOOT is a system that uses data from vehicle detectors installed on roads to automatically adjust the color of traffic signals to adapt to current traffic conditions in near real-time.

[0048] "SCATS" (Sydney Coordinated Adaptive Traffic System): This is a program-selection control system developed in Australia. It is used in approximately 42,000 intersections in over 1,800 cities across roughly 40 countries. SCATS is a system that finds the best signal control parameters (cycle length, split, and offset) for current traffic conditions by automatically selecting a plan from a library in response to data obtained from loop detectors and other devices installed on roads.

[0049] [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.

[0050] 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 passage from probe vehicles 3, and acquires signal information for intersections from a central device 5, and uses the probe information and signal information to calculate traffic indicators such as load factors necessary for generating signal control parameters for intersections.

[0051] Thus, the information processing device 2 of this embodiment functions as a "traffic indicator calculation device" necessary for generating signal control parameters. Furthermore, the information processing device 2 of this embodiment also functions as a "delay time calculation device" for each vehicle due to waiting at a signal on an on-ramp, which serves as the raw data for traffic indicators such as load factor.

[0052] 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, an IT company that provides various information services, or 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.

[0053] 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.

[0054] [Configuration of the information processing device] As shown in Figure 2, the information processing device 2 comprises a server computer 10 consisting of a workstation and various databases 21 to 24 connected to the server computer 10. The server computer 10 comprises an information processing unit 11, a storage unit 12, and a communication unit 13. The storage unit 12 is a storage device that includes at least one non-volatile memory (recording medium) consisting of an HDD (Hard Disk Drive) and an SSD (Solid State Drive), and a volatile memory (recording medium) consisting of random access memory or the like. The non-volatile memory may be removable.

[0055] The information processing unit (hereinafter also referred to as the "processing unit") 11 consists of an arithmetic processing unit including a CPU (Central Processing Unit) that reads a computer program 14 stored in the non-volatile memory of the storage unit 12 and performs information processing according to the program 14. The computer program 14 of the information processing device 2 includes a program that causes the CPU of the processing unit 11 to perform calculations of predetermined traffic indicators, such as calculating the delay time of the probe vehicle 3 due to waiting at traffic signals, and calculating the load ratio based on the delay time.

[0056] The communication unit 13 consists of a communication interface that communicates with the central device 5 and the wireless base station 7 via the public communication network 8. The communication unit 13 is capable of receiving uplink information S1 transmitted by the wireless base station 7 to its own device, and can transmit downlink information S2 generated by its own device to the wireless base station 7. The uplink information S1 includes probe information transmitted from the in-vehicle device 4. The downlink information S2 includes the link travel time calculated by the processing unit 11.

[0057] 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 communication unit 13 may be connected to the central device 5 of the traffic control center via a dedicated communication line 9, rather than via the public communication network 8.

[0058] The various databases 21-24 consist of large-capacity storage, including HDDs or SSDs. These databases 21-24 are each connected to the server computer 10 in a data transfer-enabled manner. Databases 21-24 include map database 21, probe database 22, member database 23, and signal information database 24.

[0059] Map database 21 contains road map data 25 that covers the entire country. Road map data 25 includes "intersection data" and "link data". "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.

[0060] 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

[0061] 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 road map data 25 consists of a directed graph in which a node n is set for each intersection, and each node n is connected by a pair of directed links l in opposite directions. Therefore, in the case of a one-way road, only one-way directed links l connect to node n.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] [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 consists of an arithmetic processing unit including a CPU that reads a computer program 34 stored in the non-volatile memory of the storage unit 32 and performs various information processing according to the program 34.

[0068] The storage unit 32 is a storage device that includes at least one non-volatile memory (recording medium) from among HDD and SSD, and a volatile memory (recording medium) consisting of random access memory or the like. 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.

[0069] The communication unit 33 consists of a wireless communication device permanently mounted on the probe vehicle 3, or a data communication terminal (for example, a smartphone, tablet computer, or node-type personal computer) temporarily mounted on the probe vehicle 3. The communication unit 33 includes, for example, a GPS (Global Positioning System) receiver. The processing unit 31 monitors the vehicle's current position in near real-time based on the GPS position information received by the communication unit 33. Positioning is preferably performed using a global navigation satellite system such as GPS, but other methods may also be used.

[0070] The processing unit 31 measures vehicle data such as the vehicle's position, vehicle speed, vehicle orientation, and CAN 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.

[0071] 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.

[0072] [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.

[0073] The traffic signal controller 6 within the traffic control area includes a first controller 6A that operates independently (standalone) using a point-based control method, and a second controller 6B that is controlled remotely by the central device 5 (traffic adaptation control). The processing unit 51 consists of an arithmetic processing unit including a CPU that reads a computer program 54 stored in the non-volatile memory of the storage unit 52 and performs various information processing according to the program 54.

[0074] The storage unit 52 is a storage device that includes at least one non-volatile memory (recording medium) from among HDD and SSD, and a volatile memory (recording medium) consisting of random access memory or the like. The computer program 54 of the central unit 5 includes a program for performing at least one of the following remote control (traffic adaptation control) methods: MODERATO, SCOOT, and SCATS.

[0075] 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).

[0076] The communication unit 53 consists of a communication interface that communicates with the information processing device 2 via the public communication network 8 and 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.

[0077] 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).

[0078] [Overview and problems of remote control in the comparative example] Figure 3 is a flowchart showing an overview of remote control (traffic adaptation control) related to a comparative example. As shown in Figure 3, the remote control in the comparative example includes "measurement of traffic flow" (step S1), "calculation of traffic indicators" (step S2), "calculation of signal control parameters" (step S3), and "reflection of signal control parameters" (step S4).

[0079] The processing unit 51 of the central device 5 repeatedly executes each of the processes in steps S1 to S4 at predetermined control cycles (for example, 1.0 to 2.5 minutes). The traffic flow measurement (step S1) is a process that measures the traffic flow for each entry lane at the target intersection. Conventional traffic flow measurement is a process that calculates actual data based on detection signals (pulse signals, etc.) from vehicle detectors. The actual data includes actual values ​​of traffic volume Vin, queue size Qin, and saturation traffic flow rate Sf. Note that Sf may be a set value based on the road structure.

[0080] The calculation of traffic indicators (step S2) is a process that uses the measurement results from step S1 to calculate traffic indicators for each inflow road necessary for calculating signal control parameters. The traffic indicator used in MODERATO is the load factor Lr. The load factor Lr is the ratio of traffic demand to the maximum traffic volume that can be handled in one cycle. The traffic indicator used in SCOOT and SCATS is the signal saturation Ds. The signal saturation Ds is the ratio of arriving traffic to the maximum traffic volume that can be handled during the blue time.

[0081] The formula for calculating the load factor Lr is given by equation (1) below. The formula for calculating the indicated saturation level Ds is given by equation (2) below. Lr = (Vin + k × Qin) / Sf ……(1) Ds = Vin × C / (Sf × G) ……(2) However, Vin: Traffic volume entering the intersection (vehicles / second) k: Weighting coefficient (for example, use 1.0) Qin: Traffic volume equivalent value of queue numbers (vehicles / second) Sf: Saturation traffic flow rate (vehicles / second) G: Effective blue time (seconds) C: Cycle length (seconds)

[0082] As shown in equation (1), the formula for calculating the load factor Lr includes the inflow traffic volume Vin and the number of vehicles in queue Qin as traffic variables for the inflow road. As shown in equation (2), the formula for calculating the indicated saturation Ds includes the inflow traffic volume Vin as a traffic variable for the inflow road. The processing unit 51 of the central device 5 substitutes the measured values ​​of Vin, Qin, and Sf obtained in step S1 into equation (1) or (2) to calculate at least one traffic indicator from the load factor Lr and the indicated saturation level Ds.

[0083] The calculation of signal control parameters (step S3) is a process that uses the traffic indicators calculated in step S2 to calculate signal control parameters such as the split and cycle length of the intersection to be controlled. Here, we assume that the central device 5 employs MODERATO and calculates the split and cycle length of a four-way intersection containing only two signal indications. The signal indication number is represented by "i" (i=1,2), and the direction of the inflow road for each signal indication i is represented by "j" (j=1,2).

[0084] If we let "Lij" be the load factor for each entry lane j in the given indication i, "Vij" be the traffic volume in entry lane j, "Qij" be the number of vehicles waiting in line in entry lane j, and "Sij" be the saturation traffic flow rate in entry lane j, then the load factor Lij is given by the following equation (3). Lij = (Vij + Qij) / Sij ……(3)

[0085] The processing unit 51 of the central unit 5 calculates the load factor Lri of the indication i using the following equation (4), and calculates the load factor Lrt of the entire intersection using the following equation (5). In equation (4), "maxj" means the maximum value among the j load factors Lij included in indication i. Lri = maxj(Lij) ……(4) Lrt = Lr1 + Lr2 ……(5)

[0086] Then, the processing unit 51 of the central unit 5 calculates the split λi and cycle length C of indication i using the following equations (6) and (7). In equation (6), K represents the loss time, and a1 to a3 are coefficients. λi = Lri / Lrt ……(6) C=(a1×K+a2) / (1-a3×Lrt) ……(7)

[0087] The process of applying signal control parameters (step S4) involves causing the second controller 6B of the target intersection to execute the signal control parameters calculated in step S3. Specifically, the processing unit 51 of the central unit 5 calculates a signal control command, including the light color switching timing, from the new signal control parameters, and transmits the calculated signal control command to the second controller 6B. In the case of the second controller 6B, which can calculate the light color switching timing from the signal control parameters, the signal control parameters may be transmitted directly to the second controller 6B.

[0088] As described above, in the comparative example of remote control, the traffic indicators Lr and Ds are calculated by substituting the measured values ​​of Vin, Qin, and Sf obtained from the detection signals of the vehicle detector into the definition formulas (equation (1) or (2)) for the traffic indicators Lr and Ds. Therefore, the remote control method described in the comparative example has the problem that the controlled object is limited to the traffic signal controller 6 at the intersection where the vehicle detector is installed. Furthermore, there was a fixed notion that vehicle detectors were necessary for remote control as long as the load factor of MODERATO and the indication saturation of SCOOT and SCATS were used.

[0089] By the way, as shown in equations (1) and (2), the definitions of the load factor Lr and the indicated saturation level Ds include Vin and Qin in the numerator and the saturated traffic flow rate Sf in the denominator. Therefore, if the traffic volume Vin and queue size Qin input into equations (1) and (2) are defined as variables representing their ratio to the saturated traffic flow rate Sf, then the load factor Lr and the indicated saturation level Ds can be calculated even if the true values ​​of Vin, Qin, and Sf are unknown.

[0090] In other words, if we define the traffic volume on the inflow lane as Vin = α × Sf and the queue size as Qin = β × Sf, and substitute these into equations (1) and (2), Sf cancels out in the numerator / denominator of the right-hand side, as shown in the following calculation equations (8) and (9). This means that as long as α and β can be determined, the load factor Lr and the indicated saturation level Ds can be calculated even if arbitrary values ​​are used for the saturated traffic flow rate Sf in the calculation process. By using traffic volume Vin (=α×Sf) normalized by Sf and queue size Qin (=β×Sf) normalized by Sf, the load factor Lr and indicated saturation level Ds can be calculated without determining the values ​​of Vin, Qin, and Sf themselves.

[0091] Lr = (Vin + k × Qin) / Sf = (α × Sf + k × β × Sf) / Sf =α + k × β ……(8) Ds = Vin × C / (Sf × G) =α × Sf × C / (Sf × G) =α × C / G ……(9)

[0092] Hereinafter, the traffic volume Vin (=α×Sf) and the queue size Qin (=β×Sf), expressed as a ratio to Sf, will be referred to as "normalized traffic volume" and "normalized queue size," respectively. Furthermore, the collective term for "normalized traffic volume" and "normalized queue size" will be "normalized data." As mentioned above, the saturated traffic flow rate Sf here can take on any value. On the other hand, as described later, by using the calculation results of probe information, the above-mentioned α and β can be determined, so signal control parameters can be calculated from the load factor Lr and indication saturation level Ds even without a vehicle sensor.

[0093] Therefore, in this embodiment, the traffic variables used for calculating traffic indicators for the inflow road are the normalized traffic volume Vin (=α×Sf) and the normalized queue size Qin (=β×Sf), which can be calculated from probe information (see Figure 5). In this way, by calculating traffic indicators used to calculate signal control parameters using normalized data obtained from probe information, etc., remote control can be performed even if vehicle detectors are not installed. The outline of the remote control of this embodiment will be described below with reference to Figure 4.

[0094] [Overview of remote control in this embodiment] Figure 4 is a flowchart illustrating the overview of the remote control (traffic adaptation control) in this embodiment. As shown in Figure 4, the remote control in this embodiment includes "measurement of traffic flow" (step S11), "calculation of traffic indicators" (step S12), "calculation of signal control parameters" (step S13), and "reflection of signal control parameters" (step S14).

[0095] The processing unit 11 of the information processing device 2 repeatedly executes each of the processes in steps S11 to S12 at predetermined control cycles (for example, 1.0 to 2.5 minutes). The processing unit 51 of the central device 5 repeatedly executes each of the processes in steps S13 to S14 at the same control cycle (for example, 1.0 to 2.5 minutes).

[0096] The traffic flow measurement (step S11) is a process that measures the traffic flow for each inflow lane at the target intersection. In this embodiment, the traffic flow measurement is a process that calculates normalized data using probe information as the raw data. Normalized data includes normalized traffic volume Vin (=α×Sf), which represents the ratio to Sf, and normalized queue size Qin (=β×Sf), which also represents the ratio to Sf.

[0097] The calculation of traffic indicators (step S12) is a process that uses the measurement results from step S11 to calculate traffic indicators for each inflow road necessary for calculating signal control parameters. The formula for calculating the load factor Lr is as shown in equation (1) above. The formula for calculating the indicated saturation level Ds is as shown in equation (2) above.

[0098] The processing unit 11 of the information processing device 2 substitutes the normalized data Vin (=α×Sf) and Qin (=β×Sf) obtained in step 11 into equation (1) or (2) to calculate at least one traffic indicator from the load factor Lr and the indication saturation level Ds. In this case, as is clear from equations (8) and (9) above, Sf cancels out in the numerator / denominator of the right-hand side, so even if the values ​​of Vin, Qin, and Sf themselves are unknown, the load factor Lr and the indicated saturation level Ds can be calculated.

[0099] The processing unit 11 of the information processing device 2 transmits the calculation result of the load factor Lr or the indicated saturation level Ds obtained in step S13 to the central device 5. When the processing unit 51 of the central device 5 receives the calculation result of the load factor Lr or the indicated saturation level Ds from the information processing device 2, it executes the calculation process in steps S13 and S14 using the received calculation result.

[0100] The calculation of signal control parameters (step S13) is a process that uses traffic indicators received from the information processing device 2 to calculate signal control parameters such as the split and cycle length of the controlled system. The processing content of step 13 is the same as that of step S3 in Figure 3. The process of applying signal control parameters (step S14) involves instructing the second controller 6B of the target intersection to execute the signal control parameters calculated in step S13. The processing content of step 14 is the same as that of step S4 in Figure 3.

[0101] [Method for calculating normalized data for single-unit intersections] Figure 5 is an explanatory diagram illustrating an example of a method for calculating normalized data when the target intersection for remote control is a single intersection. The meanings of the variables included in Figure 5 are as follows: Furthermore, a "standalone intersection" refers to an intersection that is subject to remote control and is controlled independently of other intersections.

[0102] 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: Assumed speed (e.g., regulated speed) (km / h) J1: Intersection upstream of the target intersection J2: Target intersection for remote control (isolated intersection)

[0103] As shown in FIG. 5, in the case of remote control of an isolated intersection, the processing unit 11 of the information processing apparatus 2 calculates the normalized traffic volume Vin and the normalized number of vehicles in the waiting queue Qin using the following formula (10) or formula (11) according to the saturation state (non-saturated / over-saturated) of the intersection. In formulas (10) and (11), "R" is the red time (seconds).

[0104] If dav ≦ R / 2 (in the case of non-saturation) Vin = {1 - R 2 / (2 × dav × C)} × Sf ……(10) If R / 2 < dav (in the case of over-saturation) Vin = (1 - R / C) × Sf Qin = {(dav - R / 2) / R} × (1 - R / C) × Sf ……(11) Hereinafter, the basis for the establishment of formulas (10) and (11) will be explained while referring to FIGS. 5 to 7.

[0105] (Relationship between link travel time and delay time) The graph at the lower part of FIG. 5 is a graph showing the travel trajectories when a plurality of vehicles pass through the link between intersections J1 and J2. The horizontal axis of the graph is the distance from intersection J1, and the vertical axis of the graph is the travel time.

[0106] When a plurality of vehicles pass through the link between intersections J1 and J2, the delay time dav per vehicle due to signal waiting is the value obtained by dividing the total delay time (area of the triangle) of all vehicles passing through intersection J2 after signal waiting by the number of vehicles. The average travel time Tt of the plurality of probe vehicles 3 can be regarded as including the above-mentioned delay time dav per vehicle.

[0107] 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 (12). dav=Tt-{L / (Ve / 3.6)} ……(12)

[0108] The processing unit 11 of the information processing device 2 extracts probe information from multiple probe vehicles 3 that passed through the link between intersections J1 and J2 during the current control cycle (for example, 1.0 to 2.5 minutes) based on the location and time of the probe information contained in the probe database 22. Then, the processing unit 11 calculates the average travel time Tt of the link by the probe vehicle 3 based on the position and time (velocity may also be used) of the extracted multiple probe information, and substitutes the calculated Tt into equation (12) to obtain the delay time dav.

[0109] (When the number of single intersections is not saturated) Figure 6 is an explanatory diagram showing the traffic conditions at intersection J2 when it is not saturated, and the relationship necessary for deriving the traffic volume Vin normalized by Sf. In the example in Figure 6, it is assumed that the vehicles stopped before intersection J2 stop overlapping at the same position just before the stop line (vertical convoy image). Also, in Figure 6, "D" is the total delay time (seconds) in one cycle, and "Gc" is the time (seconds) with the blue start as the origin, representing the time when the last vehicle passes the stop line at intersection J2.

[0110] If the entry lanes at intersection J2 are not saturated (dav ≤ R / 2), the number of vehicles that entered after the red light started (= (R + Gc) × Vin) is equal to the number of vehicles that entered by time Gc (= Gc × Sf). Therefore, the time Gc at which the last vehicle crosses the stop line is given by equation (13) below. Gc = Vin × R / (Sf - Vin) ……(13)

[0111] Furthermore, the formulas for calculating the total delay time D of the train in one cycle and the delay time dav per vehicle are given by the following formulas (14) and (15), respectively. D=0.5×{(R+Gc)×R×Vin} ……(14) dav=D / (C×Vin)=0.5×{(R+Gc)×R} / C ……(15) Substituting Gc from equation (13) into equation (15) and solving for Vin, the formula for calculating the normalized traffic volume Vin when intersection J2 is unsaturated is given by equation (10) above.

[0112] (When single-entrance intersections are oversaturated) Figure 7 is an explanatory diagram showing an example of traffic conditions at intersection J2 during a period of oversaturation. As shown in Figure 7, a simple model consisting only of driving and stopping is assumed to represent the supersaturated state, which includes vehicles waiting for two or more traffic signals. In this case, for the second and subsequent traffic signal stops, the stopping time per stop is equal to the red time R.

[0113] Pattern 1 in Figure 7 shows the traffic situation when the queue clears in the current cycle (0 cycle wait), that is, when intersection J2 is just at saturation. Pattern 2 in Figure 7 shows the traffic situation when the queue clears in the next cycle (1 cycle wait), and Pattern 3 in Figure 7 shows the traffic situation when the queue clears in the cycle after that (2 cycle wait).

[0114] In Pattern 1, dav = 0.5R and Qin = 0. In pattern 2, dav = 1.5R and Qin = (1-R / C) × Sf. In pattern 3, dav = 2.5R and Qin = 2 × (1 - R / C) × Sf. Therefore, when intersection J2 is oversaturated, the formulas for calculating the normalized traffic volume Vin and the normalized queue Qin are given by the aforementioned formula (11).

[0115] [Problems with using the average travel time of links] Figure 8 is an explanatory diagram illustrating an example of a stopping event that affects the accuracy of the DAV (daily time delay) per vehicle due to waiting at a traffic light. As shown in Figure 8, in addition to waiting at the traffic light at intersection J2, other possible stopping events that may occur when the probe vehicle 3 travels from intersection J1 to intersection J2 include, for example, the following events E1 and E2. 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.

[0116] However, in equation (12) above, the link travel time between intersections J1 and J2 is used as the average travel time Tt 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 (12) will be greater than the actual value.

[0117] In this case, the normalized traffic volume Vin and normalized queue Qin, which use the delay time dav as the source data, become inaccurate, and the load factor Lr and indication saturation Ds, which use the normalized traffic volume Vin and normalized queue Qin as the source data, also become inaccurate. Therefore, the accuracy of the signal control parameters calculated from the load factor Lr and the indicated saturation level Ds may decrease.

[0118] [Solution using the average travel time during traffic light waiting periods] In this embodiment, in order to solve the above 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 of intersection J2 (see equation (16)), 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 of intersection J2 (see equation (17)).

[0119] 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.

[0120] Figure 9 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 the section i (i=1,2...N), the length of section i Li (m), and the average speed Vi (km / h) of the 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.

[0121] 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 10). 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."

[0122] 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 10). 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.

[0123] In the above preprocessing, if the link between intersections J1 and J2 has branching nodes such as unsignaled intersections, section i may be divided at the branching nodes. Furthermore, the length Li of each section i (i=1, 2...N) included in the link does not have to be a constant distance; 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.

[0124] In the above preprocessing, the length (section length) Li of each of the multiple sections i may be set to a value smaller than the installation interval (e.g., 200m) of the vehicle sensors that will actually be 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.

[0125] 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.

[0126] [Calculation process for delay time] Figure 10 is a flowchart showing an example of the calculation process for the delay time dav per vehicle due to waiting at a traffic light, which is performed by the processing unit 11 of the information processing device 2. As shown in Figure 10, the processing unit 11 of the information processing device 2 first extracts probe information of multiple probe vehicles 3 that passed through the link between intersections J1 and J2 during the current control cycle (for example, 1.0 to 2.5 minutes) from the position and time of the probe information contained in the probe database 22 as a data collection process necessary for calculating the delay time dav (step ST10).

[0127] 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 of calculating the delay time dav (step ST11). Specifically, the processing unit 11 calculates the travel speed in section i for each probe vehicle 3 that has passed through the link, based on the position and time (speed may also be used) included in the probe information. Next, the processing unit 11 divides the sum of the travel speeds in section i for each probe vehicle 3 by the number of probe vehicles 3 to determine the average speed Vi of section i.

[0128] Next, as the second process of calculating the delay time dav, the processing unit 11 calculates the total number of sections I within the signal waiting section on the inflow road of the intersection J2 to be controlled (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 in the inflow road of the intersection J2 under control. Details of the calculation process for the total number of sections I (see Figure 11) will be described later.

[0129] Next, as the third process of calculating the delay time dav, the processing unit 11 calculates the average travel time Ttt of the signal waiting section using the calculated total number of sections I (step ST13). Specifically, the processing unit 11 calculates the average travel time Ttt using the following equation (16). As shown in equation (16), 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.

[0130]

number

[0131] Finally, as the fourth step in the calculation of the delay time dav, the processing unit 11 calculates the delay time dav per vehicle due to waiting at signals in the signal waiting section using the calculated total number of sections I and the average travel time Ttt (step ST14). Specifically, the processing unit 11 obtains the delay time dav using the following equation (17). As shown in equation (17), 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.

[0132]

number

[0133] In the calculation process for the delay time dav shown in Figure 10, the third process in step ST13 and the fourth process in step 14 may be executed by a single mathematical formula, which is formed by substituting equation (16) into Ttt on the right-hand side of equation (17).

[0134] [Calculation process for the total number of sections within the signal waiting area] Figure 11 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 11, "ML" is a variable representing the section length at which the section speed Vi exceeds the speed threshold TS. "TS" is the speed threshold, and "TL" is the distance threshold.

[0135] 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 range of a vehicle traveling at an average speed exceeding the speed threshold TS, assuming it continues traveling without the intention to stop. The distance threshold TS is a set value determined based on factors such as the magnitude of the speed threshold TS, and here we assume TL = 100m.

[0136] As shown in Figure 11, the processing unit 11 of the information processing device 2 first performs initial variable settings (step ST20). Specifically, the processing unit 11 sets the total number of intervals I, the interval length ML (the sum of the lengths of each interval Li), and the initial value of interval i to I=0, ML=0, and i=1, respectively.

[0137] 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).

[0138] 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.

[0139] 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).

[0140] 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. 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.

[0141] 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.

[0142] [Example of calculating the total number of sections within a signal waiting zone] Figure 12 is an explanatory diagram showing an actual example of the calculation of the total number of intervals I. In Figure 12, 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.

[0143] 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 of 25 km / h or less u5 = a value exceeding 25 km / h

[0144] As shown in Figure 12, 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 11 counts up to "4". Since the section speed V5 (=u5) exceeds the speed threshold TS (No in step ST21 of Figure 11), the loop from steps ST21 to ST24 in Figure 11 is exited, and the variable ML becomes L5 (step ST25 of Figure 11).

[0145] 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 11), ML is reset to 0 and the search for the total number of intervals I continues (step ST27 in Figure 11). Therefore, the total number of intervals I is counted up to "5".

[0146] 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 11. Since the section speed V8 (=u5) exceeds the speed threshold TS (No in step ST21 in Figure 11), the loop from steps ST21 to ST24 in Figure 11 is exited, and the variable ML becomes L8 (step ST25 in Figure 11).

[0147] 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 in Figure 11). Therefore, the search for the total number of intervals I continues while maintaining ML=L8 (step ST27 in Figure 11). Consequently, the total number of intervals I is counted up to "8".

[0148] Since the section speed V9 (=u5) exceeds the speed threshold TS (No in step ST21 of Figure 11), the loop from steps ST21 to ST24 in Figure 11 is exited, and the variable ML = L8 + L9 (step ST25 of Figure 11).

[0149] 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 11), 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 11), 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.

[0150] [Method for calculating delay time in the case of multiple lanes] Figures 13 and 14 are explanatory diagrams illustrating an example of a method for calculating the delay time (dav) when the link between intersections J1 and J2 has multiple lanes. As shown in Figures 13 and 14, the access road from intersection J1 to intersection J2 includes multiple lanes R1 to R3, where lane R1 is for left turns and going straight, lane R2 is for going straight, and lane R3 is for right turns only.

[0151] Furthermore, at the entrance ramp to intersection J2, the right of way for straight and left-turn lanes R1 and R2 is defined by indication φ1, and the right-turn-only lane R3 is defined by a separate indication φ2. In this case, as shown in Figure 13, if there are multiple lanes R1 and R2 that are processed with the same indication φ1, the processing unit 11 of the information processing device 2 performs a calculation process for the total number of sections I for each of the multiple lanes R1 and R2 (Figure 11), and calculates the delay time dav of the entrance road to intersection J2 based on the largest total number of sections I among the calculated total number of sections I.

[0152] For example, in Figure 13, the total number of sections I (=10) in lane R2 is greater than the total number of sections I (=7) in lane R1. Therefore, the processing unit 11 executes steps ST13 and ST14 in Figure 10 based on the total number of sections I (=10) in lane R2. Furthermore, the processing unit 11 applies the calculated delay time dav of lane R2 to equation (10) or equation (11) to calculate the normalized traffic volume Vin and the normalized queue size Qin, and calculates the load factor Lr or the indicated saturation level Ds based on these traffic indicators.

[0153] In this case, among the multiple lanes R1 and R2 processed under the same indication φ1, the delay time dav is calculated for lane R2, which has a greater degree of uncleared traffic. Therefore, it is possible to accurately calculate traffic indicators (Vin and Qin) for intersection J2 that reflect actual traffic conditions, thereby improving the accuracy of signal control parameter calculations.

[0154] As shown in Figure 14, if there is only one lane R3 that is processed with the same indication φ2, the processing unit 11 of the information processing device 2 performs the calculation process for the total number of sections I (Figure 11) only for that lane R3, and uses the delay time dav of that lane R3 as data for calculating the signal control parameters.

[0155] For example, in Figure 14, only the total number of sections I (=3) for lane R3 is calculated, so the processing unit 11 executes the processes of steps ST13 and ST14 in Figure 10 based on the total number of sections I (=3) for lane R3. Furthermore, the processing unit 11 applies the calculated delay time dav of lane R3 to equation (10) or equation (11) to calculate the normalized traffic volume Vin and the normalized queue size Qin, and calculates the load factor Lr or the indicated saturation level Ds based on these traffic indicators.

[0156] Furthermore, in the case of intersection J2 shown in Figure 14, if there are multiple right-turn-only lanes R3 and R4, the calculation process for the total number of sections I (Figure 11) should be performed for each of the multiple lanes R3 and R4, and the delay time dav of the entrance ramp to intersection J2 should be calculated based on the total number of sections I of the lane R3 (or R4) with the larger total number of sections I.

[0157] [Other variations] The embodiments described above (including modifications) are illustrative in all respects and not restrictive. The scope of the present invention includes all modifications within the scope equivalent to the configurations described in the claims.

[0158] For example, in the above embodiment, the information processing device 2 may perform the measurement of traffic flow (step S11 in Figure 4), and the central device 5 may perform the processing from the calculation of traffic indicators onward (steps S12 to S14 in Figure 4). Furthermore, if the central device 5 is capable of collecting and analyzing probe information, the central device 5 may perform all processing from traffic flow measurement to the reflection of signal control parameters (steps S11 to S14 in Figure 4). [Explanation of Symbols]

[0159] 1. Traffic signal control system 2. Information processing device (delay time calculation device) 3 Probe vehicles 3X Bus 3Y Other vehicles 4 Onboard equipment 5. Central device (delay time calculation device) 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 (Acquisition 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. An acquisition unit that acquires probe information of a probe vehicle traveling on an access road to an intersection, The system includes an information processing unit that uses the probe information as source data to perform a process to determine the end of the signal waiting section in the inflow path, The aforementioned decision process includes: A first process calculates multiple section speeds, which are the average speeds of vehicles in multiple sections formed by dividing the inflow passage, based on the probe information. The process includes a second process of determining the end of the signal waiting section in the inflow path based on the speeds of the multiple sections, The second process includes: An information processing device that includes a search process for searching for sections that satisfy the speed condition, where the section speed is less than or equal to a speed threshold, starting from the downstream side of the inflow path, and counting the sections that satisfy the speed condition as sections included in the signal waiting section.

2. The second process includes: The information processing apparatus according to claim 1, which includes a process for continuing the search process if the sum of the lengths of one or more sections that do not satisfy the speed condition is less than a distance threshold.

3. The second process includes: The information processing apparatus according to claim 1 or 2, which includes a process for determining the upstreammost section that satisfies the speed condition as the end of the signal waiting section when the sum of the lengths of the sections of one or more sections that do not satisfy the speed condition is equal to or greater than a distance threshold.

4. The length of each of the aforementioned multiple sections is: The information processing device according to claim 3, wherein the value is smaller than the installation interval of vehicle sensors for measuring vehicle speed.

5. The aforementioned information processing unit, When the end of the aforementioned signal waiting section is determined, The average travel time for the signal waiting section is calculated using the following formula (16): The information processing device according to claim 3, which calculates the delay time per vehicle due to waiting for a signal in the inflow road using the following formula (17). [Math 1] [Math 2] However, Ttt: Average travel time (seconds) in the section where traffic lights are stopped. Li: Length of interval 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. dav: Average delay time per vehicle due to waiting at traffic lights (seconds) Ve: Expected speed (e.g., regulated speed) (km / h)

6. Steps include obtaining probe information from probe vehicles traveling on the road leading into the intersection, The step includes using the probe information as source data to perform a process to determine the end of the signal waiting section in the inflow path, The aforementioned decision process includes: A first process calculates multiple section speeds, which are the average speeds of vehicles in multiple sections formed by dividing the inflow passage, based on the probe information. The process includes a second process of determining the end of the signal waiting section in the inflow path based on the speeds of the multiple sections, The second process includes: An information processing method that includes a search process for searching for sections that satisfy the speed condition, where the section speed is less than or equal to a speed threshold, starting from the downstream side of the inflow road, and counting the sections that satisfy the speed condition as sections included in the signal waiting section.

7. An acquisition unit that acquires probe information of a probe vehicle traveling on an access road to an intersection, and A computer program for causing a computer to function as an information processing unit that performs a determination process for the end of the signal waiting section in the inflow path, using the probe information as source data, The aforementioned decision process includes: A first process calculates multiple section speeds, which are the average speeds of vehicles in multiple sections formed by dividing the inflow passage, based on the probe information. The process includes a second step of determining the end of the signal waiting section in the inflow path based on the speeds of the multiple sections, The second process includes: A computer program that includes a search process for searching for sections that satisfy the speed condition, where the section speed is below a speed threshold, starting from the downstream side of the inflow road, and counting the sections that satisfy the speed condition as sections included in the signal waiting section.

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