JP6410170B2 - Travel time calculation device and travel time calculation method - Google Patents

Description

  The present invention relates to a travel time calculation device and a travel time calculation method for calculating travel time for a predetermined section of a road.

  In order to realize safe driving support such as smooth traffic control, a technology for providing traffic information such as the presence / absence of a traffic jam, a traffic jam length, and a transit time of a traffic jam section has been developed. In order to obtain such traffic information, a vehicle detector that measures the number of vehicles, occupancy, vehicle speed, or the like is installed on the road.

  For example, a vehicle detector having a pair of coils arranged upstream and downstream in the vehicle traveling direction on the road is provided, and the speed of the vehicle is detected by the installation distance of the pair of coils and the time difference when the vehicle is sensed by the pair of coils. Discloses a technique for calculating travel time (see Patent Document 1).

Japanese Patent No. 3399385

  In the case of a vehicle detector that measures the vehicle speed by sensing the vehicle between two points on the upstream and downstream sides of the road, when the vehicle is running smoothly, measure the vehicle speed accurately. Is possible. However, when a traffic jam occurs and the vehicle repeatedly starts and stops, the vehicle stops before the coil of the vehicle detector. For this reason, for example, it seems that the vehicle is stopped by the stop of the forward vehicle in front of the upstream point, and the vehicle can start from the upstream point and smoothly passes through the downstream point. In such a case, the stopping time is not taken into account, and the speed measured by the vehicle detector becomes faster than the actual speed, and the measured speed and the actual speed deviate. In addition, when a vehicle that has traveled smoothly up to a point on the upstream side temporarily stops between two points on the upstream side and the downstream side, the state of smoothly traveling is not considered, and the vehicle The speed measured by the sensor becomes slower than the actual speed, and the measured speed and the actual speed deviate. If the speed measured by the vehicle detector does not match the actual condition, the travel time of the road section calculated from the measured speed may not be obtained accurately.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a travel time calculation device and a travel time calculation method that can accurately calculate the travel time of a predetermined section of a road.

  A travel time calculation device according to an embodiment of the present invention detects a section number calculation unit that calculates the number of sections of vehicles existing in a predetermined section of a road at an arbitrary time point, and detects the number of vehicles that flow out of the section. An outflow detection unit, and a travel time calculation unit that calculates a time difference between a time point when the number of units detected by the outflow detection unit is equal to the number of sections and the arbitrary time point as a travel time of the section.

  In the travel time calculation method according to the embodiment of the present invention, the section number calculation unit calculates the number of vehicles existing in a predetermined section of the road at an arbitrary time point, and the number of vehicles flowing out from the section is calculated. A step of detecting by the outflow detection unit, and a step of calculating the time difference between the time point when the detected number is equal to the number of sections and the arbitrary time point as the travel time of the section.

  According to the present invention, it is possible to accurately calculate the travel time of a predetermined section of a road.

It is a block diagram which shows an example of a structure of the travel time calculation apparatus of this Embodiment. It is a schematic diagram which shows an example of the number of areas in the time T1 as arbitrary time points. It is a schematic diagram which shows an example of the number of areas in time T4. It is a schematic diagram which shows an example of the number of areas in the time T6. It is a schematic diagram which shows an example of the number of areas in a fixed period. It is a schematic diagram which shows an example of the number of sections in the period after a fixed period. FIG. 6 is a schematic diagram illustrating an example of the number of sections in a fixed cycle next to the fixed cycle illustrated in FIG. 5. It is a schematic diagram which shows the positional relationship of a section and a roadside communication apparatus. It is a schematic diagram which shows the state from which the vehicle which flowed into the area at the time Ta flows out of the area at the time Tb. It is a schematic diagram which shows the state which the vehicle which flowed into the area at the time Ta passes the communication area | region with a roadside communication apparatus at the time Ti. It is a flowchart which shows an example of the process sequence of the travel time calculation apparatus of this Embodiment. It is a flowchart which shows an example of the process sequence of the travel time calculation apparatus of this Embodiment.

[Description of Embodiment of Present Invention]
(1) The travel time calculation device according to the embodiment of the present invention includes a section number calculation unit that calculates the number of sections of vehicles existing in a predetermined section of a road at an arbitrary time point, and the number of vehicles that flow out of the section. And a travel time calculation unit for calculating a time difference between the time point when the number detected by the outflow detection unit is equal to the number of sections and the arbitrary time point as the travel time of the section.

(8) In the travel time calculation method according to the embodiment of the present invention, the section number calculation unit calculates the number of sections of vehicles existing in a predetermined section of the road at an arbitrary time point, and the outflow from the section The step of detecting the number of vehicles to be detected by the outflow detection unit, and the step of calculating the travel time calculation unit by using the time difference between the time point when the detected number of vehicles is equal to the number of sections and the arbitrary time point as the travel time of the section Including.

  The number of sections calculation unit calculates the number of sections of vehicles existing in a predetermined section of the road at an arbitrary time. For example, at time Tm as an arbitrary time point, the number of vehicles existing in the section is assumed to be ten. The length L of the section can be set to an appropriate length. The outflow detection unit detects the number of vehicles flowing out from the section. For example, the number of vehicles flowing out of the section can be detected by installing a vehicle detector at a downstream point (outflow point) of the section and acquiring data sensed by the vehicle detector.

  The travel time calculation unit calculates a time difference between a time point when the number detected by the outflow detection unit is equal to the number of sections and an arbitrary time point as a travel time of the section. For example, the time when the number detected by the outflow detection unit is equal to the number of sections is defined as time Tn. That is, it is assumed that outflow of 10 vehicles is detected at time Tn. If attention is paid to the last vehicle in the section at time Tm, the vehicle closest to the upstream point (inflow point) of the section at time Tm flows out of the section at time Tn. The time required to pass (that is, the travel time of the section) can be obtained by Tn−Tm. When the vehicle stops in the section due to traffic jams or the like, the number of outflows is reflected at the time when the number of sections is equal to the number of sections, so the travel time can be calculated with high accuracy.

(2) In the travel time calculation device according to an embodiment of the present invention, the outflow detection unit repeatedly detects the number of vehicles flowing out of the section at a predetermined cycle from the arbitrary time point, The travel time calculation unit calculates the travel time by multiplying the number of cycles repeated until the number of vehicles that have flowed out of the section becomes equal to the number of sections.

  The outflow detection unit repeatedly detects the number of vehicles flowing out of the section at a predetermined period (also referred to as a predetermined period) from an arbitrary time point. The predetermined period can be set to, for example, 1 minute, but is not limited to 1 minute. Assuming that an arbitrary time point is time T1, for example, the number of outflows during a predetermined period (1 minute) at each time, such as time T2, time T3, T4, T5, T6,. The travel time calculation unit calculates the travel time by multiplying a predetermined period by the number of predetermined periods repeated until the number of vehicles flowing out of the section becomes equal to the number of sections. For example, if the number of outflows becomes equal to the number of sections at time T6, the number of repeated predetermined cycles (for example, 1 minute) is 5 (T2, T3, T4, T5, T6), and the predetermined cycle is 1 minute. Therefore, the travel time is 5 × 1 minute = 5 minutes. Thereby, travel time can be calculated.

(3) In the travel time calculation device according to an embodiment of the present invention, the outflow detection unit repeatedly detects the number of vehicles flowing out of the section in the cycle from the time when the travel time calculation unit calculates the travel time. Based on the inflow detection unit that repeatedly detects the number of vehicles that flow into the section in the cycle, the number of vehicles that exist in the section during the cycle, and the number that flows out of the section An increase / decrease calculation unit for calculating an increase / decrease time of travel time in the cycle, and when the number of vehicles that have flowed out of the section in the cycle is less than the number of sections, the travel time calculated by the travel time calculation unit includes the travel time A provisional travel time calculation unit that adds the increase / decrease time calculated by the increase / decrease calculation unit to calculate the provisional travel time in the period.

  The outflow detection unit repeatedly detects the number of vehicles flowing out of the section at a predetermined period from the time when the travel time calculation unit calculates the travel time. Assuming that the time when the travel time calculation unit calculates the travel time is T6, the outflow detection unit detects the number of outflows at each time such as time T7, T8,. The inflow detection unit repeatedly detects the number of vehicles flowing into the section at a predetermined cycle. For example, it is possible to detect the number of vehicles flowing into the section by installing a vehicle detector at an upstream point (inflow point) of the section and acquiring data sensed by the vehicle sensor. The inflow detection unit detects the number of inflows at each time, for example, at times T7, T8,.

  The increase / decrease calculation unit calculates the increase / decrease time Ta of the travel time in the predetermined period based on the increase / decrease number of vehicles existing in the section during the predetermined period and the number of vehicles flowing out of the section. The increase / decrease number of vehicles existing in the section during the predetermined period is a value obtained by subtracting the number of outflows from the number of inflows in the predetermined period (for example, the time from time T6 to time T7) (inflow number-outflow number). . By dividing the increase / decrease number by the outflow number, the travel time increase / decrease time Ta in the predetermined cycle can be obtained (for example, an hourglass model).

  The provisional travel time calculation unit adds the increase / decrease time Ta calculated by the increase / decrease calculation unit to the travel time Ts calculated by the travel time calculation unit when the number of vehicles that have flowed out of the section in a predetermined cycle is less than the number of sections. Temporary travel time Ts ′ (= Ts + Ta) in a cycle is calculated. The number of sections is the number of sections existing in the section at the time when the travel time is calculated by the travel time calculation unit, that is, when the number of outflows becomes equal to the number of sections (time T6). For example, when the number of sections at time T1 becomes 0 at time T6 (when all have flowed out), the number of vehicles that have flowed into the section from time T2 to time T6 is the number that exists in the section at time T6. The case where the number of vehicles that have flowed out of the section at a predetermined cycle is less than the number of sections means that some of the vehicles that were present in the section at time T6 are still in the section, and the travel time calculation unit calculates the travel time. This means that the calculated cycle (the number of outflows = the cycle of the number of sections) has not been reached.

  Thus, the provisional travel time Ts ′ can be calculated after a predetermined period (for example, time T7) from the time T6 when the travel time calculation unit calculates the travel time Ts, and the travel time information of the section is provided at the predetermined period. be able to.

(4) In the travel time calculation device according to the embodiment of the present invention, the provisional travel time calculation unit may calculate the temporary travel most recently when the number of vehicles that have flowed out of the section in the cycle is less than the number of sections. The temporary travel time in the cycle is calculated by adding the increase / decrease time calculated by the increase / decrease calculation unit to the time.

  The provisional travel time calculation unit adds the increase / decrease time calculated by the increase / decrease calculation unit to the provisional travel time calculated most recently when the number of vehicles that have flowed out of the section in a predetermined cycle is less than the number of sections, Calculate travel time. Thus, the provisional travel time Ts ′ can be calculated every predetermined period (for example, time T8,...) From the time T6 when the travel time calculation unit calculates the travel time Ts. Can be provided.

(5) In the travel time calculation device according to the embodiment of the present invention, the provisional travel time calculation unit calculates the elapsed time when the elapsed time obtained by multiplying the number of repetitions of the period by the period is longer than the calculated temporary travel time. Instead of the provisional travel time, the elapsed time is calculated as the provisional travel time.

  When the elapsed time obtained by multiplying the number of repetitions of the predetermined period by the predetermined period is longer than the calculated temporary travel time, the temporary travel time calculation unit calculates the elapsed time as the temporary travel time instead of the calculated temporary travel time. For example, at a time Tk in the k period from the time T6 when the travel time calculation unit calculates the travel time Ts, if the predetermined period is 1 minute, the elapsed time Tc is 1 minute × k = k minutes. If the temporary travel time Ts ′ at the time Tk calculated by the temporary travel time calculation unit is Tc> Ts ′, the elapsed time Tc is set as the temporary travel time at the time Tk. That is, when the elapsed time is longer than the provisional travel time, the accuracy of the provisional travel time can be improved by adopting the actual elapsed time.

(6) The travel time calculation device according to the embodiment of the present invention acquires probe information acquisition unit that acquires probe information including the position and time of the vehicle from the vehicle that has traveled in the section, and acquires the probe information acquisition unit. And a time point specifying unit that specifies an inflow time point when the vehicle flows into the section and an outflow time point when the vehicle flows out from the section, and the number of sections calculation unit determines the arbitrary time point as the outflow time point. In this case, the number of vehicles flowing into the section between the outflow time and the inflow time is calculated as the number of sections.

  A probe information acquisition part acquires the probe information containing the position and time of the said vehicle from the vehicle which drive | worked the area. The time specifying unit specifies the inflow time when the vehicle flows into the section and the outflow time when the vehicle flows out from the section based on the acquired probe information. The number-of-sections calculation unit calculates the number of vehicles that have flowed into the section between the outflow time and the inflow time when an arbitrary time is set as the outflow time. For example, if a vehicle that flows into the section at time Ta flows out of the section at time Tb, the number of vehicles that flow into the section between time Ta and time Tb is set as the number of sections at time Tb. As a result, the number of existing sections can be calculated only by acquiring the probe information of one vehicle.

(7) In the travel time calculation device according to the embodiment of the present invention, when the acquisition time point when the probe information is acquired by the probe information acquisition unit is later than the outflow time point, the travel time calculation device between the outflow time point and the acquisition time point A section number correction unit is provided for correcting the number of sections calculated by the section number calculation unit based on the number of vehicles flowing into or out of the section.

  If the acquisition time when the probe information acquisition unit acquired the probe information is later than the outflow time, the section number correction unit is based on the number of vehicles flowing into or out of the section between the outflow time and the acquisition time, The number of sections calculated by the section number calculation unit is corrected. The case where the acquisition time point at which the probe information is acquired is after the outflow time point refers to, for example, the case where the outflow point in the section is away from the acquisition point of the probe information. For example, let Tb be the outflow time and Ti be the probe information acquisition time. The number of sections Qi at time Ti is the number of vehicles that flowed into the section from time Ta to time Tb (the number of sections calculated by the section number calculation unit) that flowed into the section from time Tb to time Ti. It can be obtained by correcting with the number obtained by subtracting the number that has flowed out of the section between the time Tb and the time Ti. Thereby, even when the point which acquires probe information is away from the outflow point of the section, the number of sections can be calculated with high accuracy.

[Details of the embodiment of the present invention]
Hereinafter, a travel time calculating apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating an example of a configuration of a travel time calculation apparatus 100 according to the present embodiment. The travel time calculation device 100 includes a control unit 10 that controls the entire device, a communication unit 11, a section number calculation unit 12, a travel time calculation unit 13, a storage unit 14 that stores necessary information, an increase / decrease travel time calculation unit 15, a provisional A travel time calculation unit 16, a probe information acquisition unit 17, a section number correction unit 18, and the like are provided.

  The communication unit 11 functions as an inflow detection unit and an outflow detection unit. That is, the communication unit 11 acquires the sensing data sensed by the vehicle detector 210 (see FIG. 2) provided at the inflow point (upstream point) of the predetermined section of the road, thereby the number of vehicles flowing into the section. (Inflow number) is detected. Further, the communication unit 11 acquires the number of vehicles flowing out of the section (the number of outflows) by obtaining the sensing data sensed by the vehicle detector 220 provided at the outflow point (downstream point) of the predetermined section of the road. To detect. The communication unit 11 detects the number of inflows and the number of outflows at predetermined intervals (for example, 1 minute). The predetermined period is not limited to 1 minute.

  The number-of-sections calculation unit 12 calculates the number of sections of vehicles existing in the road section at an arbitrary time. The number of sections is also referred to as the number of sections existing.

  The travel time calculation unit 13 calculates a time difference between a point in time when the number of outflows detected by the communication unit 11 becomes equal to the number of sections calculated by the section number calculation unit 12 and an arbitrary point in time as the travel time of the section.

  FIG. 2 is a schematic diagram showing an example of the number of sections at time T1 as an arbitrary time point. As shown in FIG. 2, the road section is L, the vehicle detector 210 is installed at the upstream point (the upstream point of traffic flow) that is the inflow point of the section, and the downstream point that is the outflow point of the section ( A vehicle detector 220 is installed at a downstream point of the traffic flow). For example, as shown in FIG. 2, at the time T1 as an arbitrary time point, the number of vehicles existing in the section (the number of sections) is 10. When attention is paid to the vehicle located at the tail among the vehicles existing in the section, it can be said that the vehicle flows into the section L from the inflow point at time T1. The number of downstream vehicles (without patterns) of vehicles (with patterns) that flowed in at time T1 is eight. Further, the length L of the section can be set to an appropriate length.

  FIG. 3 is a schematic diagram showing an example of the number of sections at time T4. Each time when a predetermined period (for example, 1 minute) has elapsed repeatedly from time T1 is represented as T2, T3, T4, T5, T6,. A time T4 shown in FIG. 3 shows a state three minutes after the time T1. As shown in FIG. 3, at time T4, out of the eight downstream vehicles that flowed in at time T1, six outflow from the section, and the number of existing vehicles in the section is four. In FIG. 3, for convenience, vehicles that flow into the section after time T2 are not shown.

  FIG. 4 is a schematic diagram showing an example of the number of sections at time T6. A time T6 shown in FIG. 4 indicates a state after 5 minutes from the time T1. As shown in FIG. 4, at time T6, the vehicle (with a pattern) that flowed in at time T1 flows out of the section, and the number (number of sections) that existed in the section at time T1 is all earned (state that flows out of the section). ) In FIG. 4, for convenience, vehicles that flow into the section after time T2 are not shown.

  In other words, at the time Tm as an arbitrary time point (time T1 in the example of FIG. 2), the number of vehicles existing in the section is set to ten. A time point at which the number of outflows detected by the communication unit 11 becomes equal to the number of sections is defined as time Tn (time T6 in the example of FIG. 4). That is, it is assumed that outflow of 10 vehicles is detected at time Tn.

  If attention is paid to the last vehicle in the section at time Tm, the vehicle closest to the upstream point (inflow point) of the section at time Tm flows out of the section at time Tn. The time required to pass (that is, the travel time of the section) can be obtained by Tn−Tm. In the example of FIGS. 2 to 4, the travel time is T6-T1 = 5 minutes. When the vehicle stops in the section due to traffic jams or the like, the number of outflows is reflected at the time when the number of sections is equal to the number of sections, so the travel time can be calculated with high accuracy.

  More specifically, the communication unit 11 detects the number of vehicles flowing out of the repeated section at a predetermined cycle from an arbitrary time point (time T1 in the example of FIG. 2). The predetermined period can be set to, for example, 1 minute, but is not limited to 1 minute. Assuming that an arbitrary time point is time T1, for example, the number of outflows during a predetermined period (1 minute) at each time, such as time T2, time T3, T4, T5, T6,.

  The travel time calculation unit 13 calculates the travel time by multiplying a predetermined period by the number of predetermined periods repeated until the number of vehicles that have flowed out of the section becomes equal to the number of sections. For example, if the number of outflows becomes equal to the number of sections at time T6, the number of repeated predetermined cycles (for example, 1 minute) is 5 (T2, T3, T4, T5, T6), and the predetermined cycle is 1 minute. Therefore, the travel time is 5 × 1 minute = 5 minutes. Thereby, travel time can be calculated.

  In the present embodiment, the travel time calculated by the travel time calculation unit 13 is also referred to as a “determined travel time” to distinguish it from the provisional travel time described later. That is, the travel time (determined travel time) is calculated at the time when the number of sections becomes 0 (that is, the number of outflows = the number of sections), and the travel time (determined travel time) was calculated. The cycle is also referred to as a fixed cycle in which the travel time is fixed.

  Next, a method for calculating the provisional travel time in a cycle other than the fixed cycle (predetermined cycle) will be described. The provisional travel time is calculated in a cycle in which the travel time is not fixed during the subtraction of the number of downstream vehicles or the number of sections, and there is a subsequent cycle in the travel time calculated in the fixed cycle (fixed travel time) It can be calculated by adding the increase / decrease travel time obtained from the increase / decrease number of the number of vehicles and the number of outflows.

  FIG. 5 is a schematic diagram showing an example of the number of sections in the fixed cycle. The fixed period shown in FIG. 5 indicates the state at time T6. The example of FIG. 5 illustrates a vehicle that has flowed into the section between time T2 and time T6 in the example of FIG. 4 that does not illustrate the inflow vehicle after time T2. As shown in FIG. 5, it is assumed that the number of sections is 20 at time T6.

  FIG. 6 is a schematic diagram showing an example of the number of sections in a cycle after the fixed cycle. The period in FIG. 6 shows the state in the period (time T7) next to the fixed period (time T6). The communication unit 11 detects the number of vehicles that repeatedly flow out of the section at a predetermined cycle from the time when the travel time calculation unit 13 calculates the travel time (for example, time T6 in FIG. 5). Assuming that the time when the travel time calculation unit 13 calculates the travel time is T6, the communication unit 11 detects the number of outflows at each time, for example, time T7, T8,. In addition, the communication unit 11 detects the number of vehicles that repeatedly flow into the section at a predetermined cycle. For example, the communication unit 11 detects the number of inflows at each time such as time T7, T8,. In this embodiment, for the sake of simplicity, the number of inflows is 4 / min and the number of outflows is 2 / min. In the example of FIG. 6, since two vehicles flow out from the section and four vehicles flow in from time T6 to time T7, the increase / decrease amount from time T6 to time T7 increases by two. .

  The increase / decrease travel time calculation unit 15 has a function as an increase / decrease calculation unit, and the increase / decrease time of the travel time in a predetermined cycle based on the increase / decrease number of vehicles existing in the section during the predetermined period and the number of vehicles flowing out of the section Ta is calculated. The increase / decrease number of vehicles existing in the section during the predetermined period is a value obtained by subtracting the number of outflows from the number of inflows in the predetermined period (for example, the time from time T6 to time T7) (inflow number-outflow number). . By dividing the increase / decrease number by the outflow number, the travel time increase / decrease time Ta in the predetermined cycle can be obtained (for example, an hourglass model). In the example of FIG. 6, the increase / decrease time Ta at time T7 is Ta = {(number of inflows−number of outflows) / number of outflows} × unit cycle time = {(4-2) / 2} × 1 = 1 minute.

  When the number of vehicles that have flowed out of the section at a predetermined cycle is less than the number of sections, the provisional travel time calculation unit 16 adds the travel time Ts calculated by the travel time calculation unit 15 to the travel time Ts calculated by the travel time calculation unit 13. Are added to calculate the provisional travel time Ts ′ (= Ts + Ta) in a predetermined cycle. The number of sections is the number of cars existing in the section at the time when the travel time is calculated by the travel time calculation unit 13 (determined cycle), that is, when the number of outflows becomes equal to the number of sections (time T6). For example, when the number of sections at time T1 (10 in the example of FIG. 2) becomes 0 at time T6 (all outflows), a vehicle that has flowed into the section between time T2 and time T6 is at time T6. The number of units that exist in the section. The case where the number of vehicles that have flowed out of the section at a predetermined cycle is less than the number of sections means that some of the vehicles that existed in the section at time T6 are still in the section (for example, the state shown in FIG. 6). This means that the fixed period (the number of outflows = the number of sections) in which the travel time is calculated by the travel time calculation unit 13 has not been reached.

  In the example shown in FIG. 6, the travel time Ts calculated by the travel time calculation unit 13 is 5 minutes, and the increase / decrease time Ta calculated by the increase / decrease travel time calculation unit 15 is 1 minute, so the provisional travel time Ts at time T7. 'Is 6 minutes (= 5 + 1). Accordingly, the provisional travel time Ts ′ can be calculated after a predetermined period (for example, time T7) from the time T6 when the travel time calculation unit 13 calculates the travel time Ts, and the travel time information of the section is provided at the predetermined period. can do.

  Similarly, at time T8, when the number of vehicles that have flowed out of the section in a predetermined cycle is less than the number of sections, the provisional travel time calculation unit 16 calculates the increase / decrease travel time to the most recently calculated provisional travel time (for example, time T7). The increase / decrease time calculated by the unit 15 is added to calculate the provisional travel time in a predetermined cycle. For example, the increase / decrease time Ta at time T8 is Ta = {(number of inflows−number of outflows) / number of outflows} × unit cycle time = {(4-2) / 2} × 1 = 1 minute. Since the provisional travel time calculated at the latest (time T7) is 6 minutes, the provisional travel time Ts ′ at time T8 is 7 minutes (= 6 + 1). Accordingly, the provisional travel time Ts ′ can be calculated every predetermined cycle (for example, time T8,...) From the time T6 when the travel time calculation unit 13 calculates the travel time Ts. Can be provided. Thereafter, the same applies to times T9, T10,.

  FIG. 7 is a schematic diagram showing an example of the number of sections in the fixed cycle next to the fixed cycle shown in FIG. The fixed cycle shown in FIG. 5 is time T6, and the next fixed cycle shown in FIG. 7 is time T16. That is, as shown in FIG. 5, the number of downstream vehicles of the vehicles that flowed in at time T6 is 18, and the number of zones existing in the zone is 20 when the two vehicles that flowed in at time T6 are included. As described above, when the number of outflows is 2 / min, the time when all the 20 units in the section flow out of the section is time T16, which is 10 minutes after time T6. That is, the vehicle that has flowed in at time T6 flows out of the section at time T16. FIG. 7 shows a point in time when the number of sections (20 units) at time T6 has all flowed out of the section. That is, at time T16, the travel time calculated by the travel time calculation unit 13 is 10 minutes. In FIG. 7, for convenience, vehicles that flow into the section after time T7 are not shown.

  If the elapsed time obtained by multiplying the number of repetitions of the predetermined cycle by the predetermined period is longer than the calculated temporary travel time, the temporary travel time calculation unit 16 calculates the elapsed time as the temporary travel time instead of the calculated temporary travel time. For example, if the predetermined period is 1 minute, the elapsed time Tc is 1 minute × k = k minutes at the time Tk of the k period from the time T6 when the travel time calculation unit 13 calculates the travel time Ts. If the temporary travel time Ts ′ at the time Tk calculated by the temporary travel time calculation unit 16 is Tc> Ts ′, the elapsed time Tc is set as the temporary travel time at the time Tk. That is, when the elapsed time is longer than the provisional travel time, the accuracy of the provisional travel time can be improved by adopting the actual elapsed time.

  The probe information acquisition unit 17 acquires probe information including the position and time of the vehicle from the vehicle that has traveled in the section. The probe information acquisition unit 17 is, for example, connected to a road communication device (base station) 300 described later having a wireless communication function for ITS (Intelligent Transport Systems) using a UHF band frequency band. Communication function. The probe information is also referred to as uplink information, and can include, for example, a vehicle ID, a vehicle position, a time, a vehicle speed, a vehicle orientation, and the like. When the vehicle passes through the communication area with the road communication device 300, the road communication device 300 acquires probe information from the vehicle and outputs the probe information to the travel time calculation device 100.

  The control unit 10 has a function as a time point specifying unit, and specifies the inflow time Ta when the vehicle flows into the section and the outflow time Tb out of the section based on the probe information acquired by the probe information acquiring unit 17.

  The section number calculation unit 12 calculates, as the number of sections, the number of vehicles that have flowed into the section between the outflow time point and the inflow time point when an arbitrary time point is the outflow time point.

  For example, if a vehicle that flows into the section at time Ta flows out of the section at time Tb, the number of vehicles that flow into the section between time Ta and time Tb is set as the number of sections at time Tb. If the number of inflows into the section (the number of vehicles that have passed through the vehicle detector 210) is Qa, the number of sections can be obtained by equation (1).

  As a result, the number of existing sections can be calculated only by acquiring the probe information of one vehicle.

  The above example assumes that the road communication device 300 is installed at the outflow point of the section. However, when the road communication device 300 is away from the outflow point of the section, as described below, The number of sections may be corrected.

  FIG. 8 is a schematic diagram showing a positional relationship between the section and the road communication device 300. As shown in FIG. 8, it is assumed that the road communication device 300 is installed further downstream from the vehicle detector 220 installed at the downstream point of the section. Then, as shown in FIG. 8, it is assumed that the vehicle x flows into the section at time Ta.

  FIG. 9 is a schematic diagram showing a state where a vehicle that has flowed into the section at time Ta flows out of the section at time Tb. In this case, the number of vehicles flowing into the section between time Ta and time Tb can be set as the number of sections at time Tb.

  FIG. 10 is a schematic diagram showing a state in which the vehicle that has flowed into the section at time Ta passes through the communication area with the roadside communication device 300 at time Ti. When the acquisition time Ti at which the probe information is acquired by the probe information acquisition unit 17 is later than the outflow time Tb, the section number correction unit 18 enters or exits the section between the outflow time Tb and the acquisition time Ti. The number of sections calculated by the section number calculation unit is corrected based on the number of sections. The case where the acquisition time Ti at which the probe information is acquired is later than the outflow time Tb refers to the case where the outflow point in the section is away from the acquisition point of the probe information, as shown in FIGS.

  The number of sections Qi at time Ti can be obtained by Expression (2). That is, the number of sections Qi at time Ti is the number of vehicles that flowed into the section from time Ta to time Tb (the number of sections calculated by the section number calculation unit 12). It can be obtained by correcting the number of vehicles flowing out of the section from the time Tb to the time Ti by subtracting the number of vehicles flowing out of the section. Thereby, even when the point which acquires probe information is away from the outflow point of the section, the number of sections can be calculated with high accuracy.

  Next, a method for estimating the number of sections in a period in which probe information cannot be collected will be described.

  The probe information cannot be collected until the vehicle reaches the communication area of the roadside communication device 300. Therefore, in a period in which probe information cannot be collected, the accuracy of the number of sections can be maintained by using a statistical method such as a Kalman filter.

  E (t) is the true value (unknown) of the number of sections at time t (variable to be estimated), y (t) is the estimated number of sections obtained from the probe information at time t, and u (t) is the time t And ξ (t) is the error (unknown) of the observation equation at time t, and ξ (t) is the error (unknown) of the observation equation at time t. (3) and the observation equation can be expressed by equation (4).

  At this time, assuming that the error characteristics of ξ and η are ξ (t): N (0, M (t)) and η (t): N (0, N (t)) (N (average, variance) And the optimal estimate Es (t) and the error (variance) Σ (t) of the state variable E (t) at time t are expressed by Equation (5) and Equation (7), respectively. be able to. In this case, the Kalman gain K (t) can be expressed by Expression (6). In addition, the initial value Es (0) of the estimated value and the initial value Σ (0) of the error variance can be expressed by Expression (8) and Expression (9), respectively. Note that the initial value of E (0) is N (α, B)).

  Next, the operation of travel time calculation apparatus 100 according to the present embodiment will be described. 11 and 12 are flowcharts showing an example of the processing procedure of the travel time calculation apparatus 100 according to the present embodiment. Hereinafter, for the sake of convenience, the processing subject will be described as the control unit 10. Further, (t) represents a period with a parameter (for example, the current period), and (t−1) represents a period before the period. The control unit 10 sets the initial number (number of initial sections) to Q (t−1) (S11), resets the counter C, and sets C = 0 (S12). The counter counts the number of repetitions of a predetermined period.

  The control unit 10 sets the initial downstream vehicle number Ql (t−1) to Q (t−1). That is, Ql (t-1) = Q (t-1) is set (S13). The control unit 10 sets the initial travel time of the section to Ts (t−1) (S14).

  The control unit 10 acquires the number Qi (t) of inflows into the section and the number Qo (t) of outflows from the section (S15), and the existing number (number of sections) Q (t) is expressed as Q (t) = Q ( t-1) + Qi (t) -Qo (t) is calculated (S16). If the number of existing vehicles in a certain predetermined cycle is Q (t−1), the number of existing vehicles in the next predetermined cycle is represented by Q (t).

  The control unit 10 calculates the number of downstream vehicles Ql (t) by Ql (t) = Ql (t−1) −Qo (t) (S17). If the number of downstream vehicles in a certain predetermined period is Ql (t−1), the number of downstream vehicles in the next predetermined period is represented by Ql (t).

  The controller 10 increments the counter C by adding 1 (S18), and determines whether or not the number of downstream vehicles Ql (t) ≦ 0 (S19). When the number of downstream vehicles Ql (t) ≦ 0 (YES in S19), the control unit 10 calculates the travel time Ts (t) by Ts (t) = C × unit cycle time (S20). The unit cycle time is a predetermined cycle time, for example, 1 minute.

  The control unit 10 resets the counter C by setting the counter C = 0 (S21), and sets the number of existing vehicles (number of sections) Q (t) as the number of downstream vehicles Ql (t). That is, Ql (t) = Q (t) is set (S22).

  On the other hand, if the number of downstream vehicles Ql (t) ≦ 0 is not satisfied (NO in S19), the control unit 10 sets the increase / decrease travel time Ta as Ta = {(Qi (t) −Qo (t)) / Qo (t)}. × Calculated by unit cycle time (S23). The unit cycle time is the above-mentioned predetermined cycle, for example, 1 minute. The control unit 10 calculates the provisional travel time Ts (t) by Ts (t) = Ts (t−1) + Ta (S24). Assuming that the provisional travel time in a certain predetermined period is Ts (t−1), the provisional travel time in the next predetermined period is represented by Ts (t).

  The control unit 10 calculates the elapsed time Tc by Tc = C × unit cycle time (S25), and determines whether Tc> Ts (t) is satisfied (S26). When Tc> Ts (t) is satisfied (YES in S26), the control unit 10 sets the elapsed time Tc as the provisional travel time Ts (t) (S27). If Tc> Ts (t) is not satisfied (NO in S26), the control unit 10 performs the process of step S28 described later without performing the process of step S27.

  The control unit 10 determines whether or not to end the process (S28). If the process is not ended (NO in S28), the process after step S15 is performed and the process is ended (YES in S28). Exit.

  Travel time calculation apparatus 100 of the present embodiment can also be realized using a general-purpose computer that includes a CPU, a RAM, and the like. That is, a computer program that defines the processing procedure as shown in FIGS. 11 and 12 is recorded on a computer program recording medium such as a CD, DVD, or USB memory, and the computer program is loaded into a RAM provided in the computer. By executing the computer program on the CPU, the travel time calculating device 100 can be realized on the computer.

  Conventionally, the travel time of a predetermined section of a road can be obtained by the following method. For example, (1) travel time = section length / measured speed, (2) travel time = existing number / outflow number

  However, in a situation where there is a traffic jam with stopping / starting that occurs when the road is closed, for example, loop detectors cannot reflect the time stopped in the travel speed to the travel time. With the calculation method (1) described above, an accurate travel time cannot be obtained. Further, when the travel time is calculated from the number of existing vehicles and the number of outflows as in (2) above, when the number of outflows is less than 1 / min, the travel time fluctuates and the travel time is excessively calculated. There is a case. That is, in a traffic jam state, the travel time calculated by increasing or decreasing the number of outflows is greatly changed.

  According to the present embodiment, since the travel time is calculated at the timing when the number of vehicles existing in a predetermined section is earned, the stop time of the vehicle can also be reflected in the travel time. Moreover, since the travel time is not calculated by directly using the number of outflows having a large variation for each predetermined period, it is possible to suppress the travel time fluctuation even in a traffic jam situation. In addition, since the provisional travel time (provisional travel time) is obtained every predetermined period, the travel time in the section can be provided (information can be provided) every predetermined period.

  In the present embodiment, the vehicle detectors 210 and 220 are loop type vehicle detectors. However, the vehicle detectors 210 and 220 are not limited to the loop type vehicle sensor, and may be of other types. There may be.

  The disclosed embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 10 Control part 11 Communication part 12 Section number calculation part 13 Travel time calculation part 14 Storage part 15 Increase / decrease travel time calculation part 16 Provisional travel time calculation part 17 Probe information acquisition part 18 Section number correction part 210,220 Vehicle detector 300 Road communication apparatus

Claims (8)

A section number calculation unit that calculates the number of sections of vehicles existing in a predetermined section of the road at an arbitrary time;
An outflow detection unit for detecting the number of vehicles flowing out of the section;
A travel time calculation device comprising: a travel time calculation unit that calculates a time difference between a time point when the number detected by the outflow detection unit is equal to the number of sections and the arbitrary time point as a travel time of the section. The outflow detector is
The number of vehicles flowing out of the section at a predetermined cycle from the arbitrary time point is repeatedly detected,
The travel time calculation unit
2. The travel time calculation according to claim 1, wherein the travel time is calculated by multiplying the number of cycles repeated until the number of vehicles that have flowed out of the section becomes equal to the number of the sections. apparatus. The outflow detector is
The travel time calculation unit repeatedly detects the number of vehicles flowing out of the section in the cycle from the time when the travel time is calculated,
An inflow detection unit that repeatedly detects the number of vehicles flowing into the section in the cycle;
An increase / decrease calculation unit that calculates the increase / decrease time of travel time in the cycle based on the increase / decrease number of vehicles existing in the interval during the cycle and the number of vehicles flowing out of the interval;
When the number of vehicles that have flowed out of the section in the cycle is less than the number of sections calculated at the time when the travel time calculation unit calculated the travel time, the increase / decrease calculation is performed on the travel time calculated by the travel time calculation unit. The travel time calculation device according to claim 2, further comprising: a provisional travel time calculation unit that calculates the provisional travel time in the cycle by adding the increase / decrease times calculated by the unit. The provisional travel time calculation unit
When the number of vehicles that have flowed out of the section in the period is less than the number of sections, the provisional travel time in the period is calculated by adding the increase / decrease time calculated in the increase / decrease calculation unit to the provisional travel time calculated most recently. The travel time calculation device according to claim 3, wherein The provisional travel time calculation unit
The elapsed time is calculated as the provisional travel time instead of the calculated provisional travel time when the elapsed time obtained by multiplying the number of repetitions of the period by the period is longer than the calculated provisional travel time. The travel time calculation device according to claim 4. A probe information acquisition unit that acquires probe information including the position and time of the vehicle from a vehicle that has traveled in the section;
Based on the probe information acquired by the probe information acquisition unit, a time point specifying unit for specifying the inflow time point when the vehicle flows into the section and the outflow time point that flows out of the section, and
The section number calculation unit
The number of vehicles flowing into the section between the outflow time and the inflow time when the arbitrary time is set as the outflow time is calculated as the number of sections. The travel time calculation apparatus according to any one of the above.   When the acquisition time point when the probe information is acquired by the probe information acquisition unit is after the outflow time point, based on the number of vehicles flowing into or out of the section between the outflow time point and the acquisition time point, The travel time calculating device according to claim 6, further comprising a section number correcting unit that corrects the number of sections calculated by the section number calculating unit. A section number calculating unit calculating the number of sections of vehicles existing in a predetermined section of the road at an arbitrary time;
A step of detecting the number of vehicles flowing out of the section by the outflow detection unit;
A travel time calculation method including a step in which a travel time calculation unit calculates a time difference between a time point when the detected number is equal to the number of sections and an arbitrary time point as a travel time of the section.

Images