JP5169140B2 - Link cost calculation device and method, route guidance system, and computer program - Google Patents

Description

  The present invention relates to a link cost calculation apparatus and method for calculating a link cost of a link including an intersection, a computer program for executing the method, and a route guidance system using the apparatus.

The road travel time data is necessary for grasping road congestion and calculating the optimum route. Since the travel time of this road changes every moment, it is important to grasp the current travel time data in real time.
For this reason, the travel time data of the road on which each vehicle actually traveled is accumulated by a vehicle detector or an optical beacon, and the travel time for each link is calculated based on a large number of travel time data, and the related organizations and vehicles Has already been proposed (see Patent Documents 1 and 2).

The vehicle that has received the travel time for each link adopts the travel time for each link as the link cost, and selects the route that minimizes the link cost (total travel time) from its departure point to the destination. The driver searches and presents a route that can reach the destination in the shortest time to the driver.
JP 2006-344006 A JP 2004-101504 A

On the other hand, since reduction of carbon dioxide emissions from automobiles is regarded as an important measure against global warming, the relationship between vehicle behavior and fuel consumption (carbon dioxide emissions) under traffic congestion is based on actual driving experiments. An estimation model has been reported that formulates and quantitatively evaluates the fuel consumption of an automobile by three elements of travel distance, travel time, and vehicle speed variation characteristics (Non-Patent Document 1).
“Model for estimating carbon dioxide emissions from automobiles in urban road traffic” Proceedings of Japan Society of Civil Engineers No.695 / IV-54, PP125-136, 2002.1

As described above, according to the fuel consumption estimation model described in Non-Patent Document 1, the fuel consumption of a vehicle can be quantitatively evaluated based on the three elements of its travel distance, travel time, and vehicle speed variation characteristics.
For this reason, if the fuel consumption defined by the above estimation model is adopted as the link cost, the fuel cost can be determined by searching for the route that minimizes the link cost (total fuel consumption) from the departure point to the destination. It should be possible to build a route guidance system that can present the route with the least amount of consumption to the driver.

However, in the conventional travel time providing system, the travel time for each link is defined as the link cost with the average value of a large number of travel time data. Therefore, the three elements for specifying the estimation model are accurately specified. It cannot be reflected.
In other words, if the average travel time of the link is known, it is possible to identify the travel distance and travel time among the three elements for identifying the fuel consumption estimation model, but the vehicle speed fluctuations due to stop / start It is not possible to properly specify the characteristics, and it is impossible to construct a route guidance system using the fuel consumption amount as a link cost.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a link cost calculation device and the like that can calculate a link cost that is closer to the actual state of vehicle travel in consideration of fluctuations in vehicle speed due to stopping and starting. And

A link cost calculation device according to the present invention (Claim 1) is a link cost calculation device for calculating a link cost of a link including an intersection, and travels on the link using signal information generated by an infrastructure side device. The vehicle is characterized by comprising estimation means for estimating the number of stops at which the vehicle to stop stops at the downstream intersection of the link, and calculation means for calculating the link cost based on the estimated number of stops.

According to the link cost calculating apparatus of the present invention, the estimating means estimates the number of stops at which a vehicle traveling on the link stops at the downstream intersection of the link, and the calculating means calculates the link cost based on the estimated number of stops. Therefore, it is possible to provide a link cost that is closer to the actual state of vehicle travel in consideration of fluctuations in vehicle speed due to stop / start.
For this reason, as will be described later in the embodiments, for example, fuel consumption that requires vehicle speed fluctuation characteristics can be adopted as the link cost, and the versatility of the route guidance system using the link cost can be improved. it can.

In the link cost calculation apparatus of the present invention, the estimation means can specifically perform the process of estimating the number of stops based on the number of queues at the downstream intersection and the number of profits at the downstream intersection (claim). Item 2). More specifically, it can be estimated as “the number of stops = the number of queues / the number of earners”, and this calculation formula represents the average value of the number of stops due to signal waiting at the downstream intersection.
Further, it is preferable that the estimation process is performed on condition that the number of queues at the downstream intersection is larger than the number of earnings in one signal cycle at the downstream intersection (claim 3). The reason is that the vehicle always stops at the downstream intersection under such conditions.

In the link cost calculation apparatus according to the present invention, the estimation means performs the process of estimating the number of stops based on a probability that when the upstream intersection of the link passes in blue, the downstream intersection of the link can pass in blue. (Claim 4).
More specifically, it can be estimated as “the number of stops = 1−the probability (expected value) of passing the downstream intersection of the link in blue when passing through the upstream intersection of the link in blue”. It represents the probability (expected value) of reaching the downstream intersection in red when passing through the upstream intersection in blue.
In the estimation process, the number of queues at the downstream intersection is equal to or less than the number of earnings in one signal cycle at the downstream intersection (claim 9), and the signal cycle length at the upstream intersection is the downstream intersection. It is desirable to perform it on condition that it is the same as the signal cycle length in (claim 6). The reason is that if the number of queues at the downstream intersection is less than or equal to the number of earners, the queue is always cleared in one cycle at the downstream intersection. In this case, if each signal cycle length is the same, This is because the difference in signal switching timing at the downstream intersection becomes constant in each cycle, and the estimation based on the above calculation formula is more reliably established.

In this case, more specifically, the estimation means can perform the estimation process of the number of stops based on the following equation (1).
P = 1- [min (t1 + G1, t2 + G2) -max (t1, t2)] / G1 (1)
However,
P: Number of stops
t1: Start time of green light at upstream intersection
t2: Departure time of the link start point for the vehicle to pass the link end point at the green light start time of the downstream intersection
G1: Green traffic time at upstream intersection
G2: Green traffic time at downstream intersection

Furthermore, in the link cost calculation apparatus of the present invention, the estimation means can perform the estimation process of the number of stops based on a green signal time and a signal cycle length of the downstream intersection (Claim 7). More specifically, it can be estimated as “the number of stops = 1−the green signal time of the downstream intersection / the signal cycle length of the downstream intersection”, and this calculation formula indicates the probability (expected value) that the vehicle reaches the downstream intersection in red. ).
In the estimation process, the number of queues at the downstream intersection is equal to or less than the number of earnings in one signal cycle at the downstream intersection (claim 9), and the signal cycle length at the upstream intersection is the downstream intersection. It is desirable to carry out on condition that it is not the same as the signal cycle length in (claim 8). The reason is that if the number of queues at the downstream intersection is less than or equal to the number of earners, the queue is always cleared in one cycle at the downstream intersection. In this case, if each signal cycle length is not the same, the upstream intersection and This is because the difference in signal switching timing at the downstream intersection changes for each cycle, and the estimation based on the above calculation formula is more reliably established.

The route search system of the present invention (Claim 10) uses the link cost calculation device (Claims 1 to 9) and the link cost calculated for each link from the starting point of the vehicle. And a route search device for searching for a route to the destination.
According to this route search system, the link cost calculation device provides a link cost that is closer to the actual state of vehicle travel in consideration of vehicle speed fluctuations due to stop / start, so for example, link fuel consumption that requires vehicle speed fluctuation characteristics. It can be adopted as a cost. For this reason, the route with the smallest fuel consumption can be presented to the driver by searching for the route having the minimum link cost (total fuel consumption) from the departure point to the destination.

The route search system may consist with the infrastructure side device, and the infrastructure side device can communicate with the vehicle-mounted device.
In this case, the link cost calculation device may be incorporated in the infrastructure side device, and the route search device may be incorporated in the in-vehicle device (Claim 11), and both the link cost calculation device and the route search device may be incorporated. You may make it incorporate in the said infrastructure side apparatus (Claim 12). Further, the estimation unit of the link cost calculation device may be incorporated in the infrastructure side device, and the calculation unit of the calculation device and the route search device may be incorporated in the in-vehicle device (claim 13).

The computer program of the present invention (Claim 14) is a program for causing a computer to execute the link cost calculation apparatus of the present invention (Claim 1), and has the same effects as the calculation method.
The link cost calculation method of the present invention (Claim 15) is a method performed by the link cost calculation device of the present invention (Claim 1), and has the same effects as the calculation device.

  As described above, according to the present invention, the number of stops at which a vehicle traveling on a link stops at the downstream intersection of the link is estimated, and the link cost is calculated based on the estimated number of stops. It is possible to provide a link cost that is closer to the actual state of vehicle travel in consideration of the fluctuation of the vehicle.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[Overall system configuration]
FIG. 1 shows the overall configuration of a traffic signal control system employing the present invention.
As shown in FIG. 1, the traffic signal control system according to the present embodiment includes a traffic signal 1, a vehicle-mounted device 2 (see FIG. 2), a road device 3, a central device 4, a vehicle 5 on which the vehicle-mounted device 2 is mounted.

This traffic signal control system also provides the in-vehicle device 2 with the link cost calculated for each link by the central device 4 and uses the link cost to minimize the link cost from the starting point of the vehicle 5 to the destination. It also has a function as a route search system in which the in-vehicle device 2 searches for a route to become.
In FIG. 1, for simplification of illustration, only one signal lamp 1b is depicted at each intersection Ji. However, in each actual intersection Ji, for example, as shown in FIG. Four signal lamps 1b are installed for going up and down.

As shown in FIG. 1, in the present embodiment, the road structure of the control area managed by the central device 4 is composed of a road RM in the north-south direction and a road RS in the east-west direction.
Further, as shown in FIG. 2, the road RM includes an upward line RM1 for the north and a downward line RM2 for the south, and the road RS includes an upstream line RS1 for the east and a downward line RS2 for the west. It shall be.

The terminal control device 1a of each traffic signal 1 is installed at each of a plurality of intersections Ji (i = 1 to 12), and is connected to a router 7 via a communication line 6 such as a telephone line. The router 7 is connected to a central device 4 in the traffic control center, and the central device 4 constitutes a local area network (LAN) with each traffic signal 1 at the intersection Ji in the control area.
Therefore, the central device 4 can bidirectionally communicate with each traffic signal 1, and each traffic signal 1 can also communicate bidirectionally with other traffic signals 1. The central device 4 may be installed on the road instead of the traffic control center.

The road device 3 is arranged for each of the upper and lower lines in the vicinity of the downstream side of each intersection Ji, and is connected to the router 7 via the communication line 6. Therefore, the central device 4 can also perform bidirectional communication with each of these on-road devices 3.
This on-road device 3 is a narrow-range communication device such as an optical beacon or DSRC (Dedicated Short Range Communication), and wirelessly communicates various information with the in-vehicle device 2 mounted on the vehicle 5. Can do.

When the vehicle 5 passes through the road device 3, the in-vehicle device 2 wirelessly transmits its own vehicle ID and the like as uplink information to the road device 3. The road device 3 stores the uplink reception time from each vehicle 5 in association with its own road device ID and the vehicle ID, and centrally stores the information of the reception time with these IDs (hereinafter referred to as time information S1). Transmit to device 4.
On the other hand, the central device 4 receives and accumulates time information S1 from each on-road device 3, and calculates a link cost comprising travel time and fuel consumption for each link based on the accumulated time information S1. The link cost calculation method performed by the central device 4 will be described later.

Further, the central device 4 transmits traffic information S2 such as traffic jam information to each road device 3 at regular intervals (for example, every 5 minutes), and each road device 3 uses the received traffic information S2 as downlink information. Wireless transmission is performed to the in-vehicle device 2, and the in-vehicle device 2 of each vehicle 5 receives the traffic information S2.
The link means a road section between adjacent intersections Ji. Therefore, in the present embodiment, it means the distance from a specific road device 3 to the next road device 3, and one intersection Ji is always included in one link.

[Central equipment]
FIG. 3 is a block diagram showing the configuration of the central device 4.
As illustrated in FIG. 3, the central device 4 includes a control unit 401, a display unit 402, a communication unit 403, a storage unit 404, and an operation unit 405.
The control unit 401 of the central device 4 includes a workstation (WS), a personal computer (PC), and the like, and collects, processes (calculates) and records various traffic information from the traffic signal device 1 and the road device 3, and performs signal control and Provide information in an integrated manner. The control unit 401 of the central device 4 is connected to the hardware units via an internal bus, and also controls the operations of these units.

The control unit 401 of the central device 4 adjusts the traffic signal 1 on the same road to the traffic signal 1 at the intersection Ji belonging to its own network, or wide area control that extends this system control to the road network. (Surface control) is performed, and traffic sensitive control is performed in which signal control parameters (split, cycle length, offset, etc.) are set according to traffic conditions.
Further, the control unit 401 of the central device 4 calculates the link cost (travel time and fuel consumption) in its own control area, and this calculation method will be described later.

The communication unit 403 of the central device 4 is a communication interface connected to the LAN side via the communication line 6 and transmits traffic information S2 including traffic jam information to each on-road device 3 and a signal lamp every predetermined time. The signal control command S3 related to the timing of switching the lamp color 1b and the like, and the control type information S4 related to the type of traffic control performed by itself are transmitted to each traffic signal device 1.
The signal control command S3 and the signal type information S4 are transmitted every signal control parameter calculation cycle (for example, 1.0 to 2.5 minutes), and the traffic information S2 is transmitted every five minutes, for example.

The storage unit 404 of the central device 4 is composed of a hard disk, a semiconductor memory, and the like. A calculation program for signal control parameters used for calculation of link costs (travel time and fuel consumption), which will be described later, and various traffic-sensitive controls, and the like. I remember it.
The storage unit 404 of the central device 4 temporarily stores the signal control command S3, the traffic information S2 and the control type information S4 generated by the control unit 401, and the time information S1 acquired from the LAN side.

The display unit 402 of the central device 4 is composed of a road map of an area managed by the central device 4 and a display screen on which positions of all traffic signals 1 and road devices 3 on the road map are displayed. And traffic conditions such as accidents, and disasters such as large-scale accidents and earthquakes occurring in the control area.
The operation unit 405 of the central device 4 includes an input interface such as a keyboard and a mouse. The operation unit 405 allows the central operator to perform a display switching operation on the display unit 402.

[Traffic signal]
FIG. 2 is a schematic diagram showing the overall configuration of each traffic signal 1 included in the control area.
As shown in FIG. 2, the traffic signal 1 of the present embodiment includes four signal lamps 1b installed on the upper and lower lines RM1, RM2 of the road RM and the upper and lower lines RS1, RS2 of the road RS, and the signal lamp 1b. And a terminal control device 1 a connected via a communication line 8.
The terminal control device 1a receives the signal control command S3 from the central device 4, and based on the signal control command S3, turns on, turns off, and blinks the signal lights such as blue, yellow, red, and right turn arrow of each signal lamp 1b. To control.

FIG. 4 is a block diagram showing a configuration of the terminal control device 1a.
As illustrated in FIG. 4, the terminal control device 1 a includes a control unit 101, a lamp driving unit 102, a communication unit 103, and a storage unit 104.
The control unit 101 of the terminal control device 1a is composed of one or a plurality of microcomputers. The control unit 101 is connected to the lamp driving unit 102, the communication unit 103, and the storage unit 104 via an internal bus, and the control unit 101 controls operations of these hardware units.

The control unit 101 of the terminal control device 1a drives each signal lamp 1b according to a signal control command S3 that is an output as a result of the traffic sensitivity control performed by the central device 4, and each signal lamp at a predetermined timing based on the command S3. The signal lamp color of the device 1b is switched.
The lamp driving unit 102 includes a semiconductor relay (not shown). Based on the control signal from the control unit 101, the signal lamps of the respective colors corresponding to the blue, yellow, and red lamps of the plurality of signal lamps 1b. The AC voltage (AC100V) or DC voltage supplied to is turned on / off.

The communication unit 103 of the terminal control device 1a is a communication interface that performs wired communication between the central device 4 and the road device 3, receives the signal control command S3 and the control type information S4 from the central device 4, and detects the vehicle detector. If there is (not shown), the sensing signal is also received. Note that the communication unit 103 may perform wireless communication with the central device 4 or the road device 3.
The storage unit 104 of the terminal control device 1a includes a hard disk, a semiconductor memory, and the like, and stores traffic information S2, a signal control command S3, control type information S4, and the like received by the communication unit 103.

[In-vehicle device]
The in-vehicle device 2 mounted on the vehicle 5 has a communication function for wirelessly communicating various information with the on-road device 3 and a navigation function (route search function) for guiding to a destination set by the passenger. FIG. 5 is a block diagram showing the configuration of the in-vehicle device 2.
As illustrated in FIG. 5, the in-vehicle device 2 includes a GPS processing unit 201, an orientation sensor 202, a vehicle speed acquisition unit 203, a communication unit 204, a storage unit 205, an operation unit 206, a display unit 207, an audio output unit 208, and a processing unit 209. Etc.

The GPS processing unit 201 receives a GPS signal from a GPS satellite, and measures the position (latitude, longitude, and altitude) of the vehicle 5 based on time information, GPS satellite orbit, positioning correction information, and the like included in the GPS signal. To do.
The direction sensor 202 is constituted by an optical fiber gyro or the like, and measures the direction and angular velocity of the vehicle 5. The vehicle speed acquisition unit 203 acquires the speed data of the vehicle 5 measured by a vehicle speed sensor (not shown) detecting the angular speed of the wheels.

The communication unit 204 of the in-vehicle device 2 is a communication interface that performs two-way communication with the road device 3 wirelessly. When the vehicle 5 travels toward the intersection Ji and enters the narrow area communication area of the road device 3, the road device 3 receives downlink information such as traffic information S2 transmitted by the terminal 3 and transmits uplink information including its own vehicle ID and the like to the roadside device 3.
The storage unit 205 of the in-vehicle device 2 is composed of a hard disk, a semiconductor memory, and the like, and stores the traffic information S2 received by the communication unit 204. The storage unit 205 stores road map data.

This road map data includes the intersection data that associates the intersection ID with the position of the intersection, the link ID, the link start point, the end point, and the interpolation point (corresponding to the point where the road bends), and the link start point. It consists of link data that links the link ID of the link to be connected, the link ID of the link connected to the end point of the link, and the link cost.
For example, there are as many link costs as the number of combinations of a link and its end point, and after entering the start point of the link, exit the end point of the link and enter the start point of the next link to be connected. Costs (travel time and fuel consumption) required until the time is set.
That is, the link cost includes the cost required to travel from the start point of the link to the end point, and the cost required to travel from the end point of the link to the start point of the next link, that is, the cost required to pass through the intersection. It is included.

The operation unit 206 of the in-vehicle device 2 includes a touch panel, buttons, and the like, and a passenger of the vehicle 5 including a driver can set a destination.
The display unit 207 of the in-vehicle device 2 includes a monitor device (not shown) attached to the dashboard portion of the vehicle 5 and displays the image data created by the processing unit 209 to the passenger. The audio output unit 208 outputs the audio data created by the processing unit 209 from a speaker (not shown).

The processing unit 209 of the in-vehicle device 2 includes one or a plurality of microcomputers and the like, and includes a GPS processing unit 201, a direction sensor 202, a vehicle speed acquisition unit 203, a communication unit 204, a storage unit 205, an operation unit 206, and a display unit. Each process of the audio output unit 208 is controlled.
Further, the processing unit 209 includes each data of the position of the vehicle 5 measured by the GPS processing unit 201, the azimuth and angular velocity of the vehicle 5 measured by the direction sensor 202, the speed of the vehicle 5 acquired by the vehicle speed acquisition unit 203, and the storage unit 205. Based on the road map data stored in the map, the map matching process is performed to determine the position of the vehicle 5 on the road map data link.

[Calculation and provision of link cost by central unit]
Next, calculation and provision of the link cost executed by the control unit 401 of the central apparatus 4 will be described with reference to FIGS. 2 and 6. In the present embodiment, the control unit 401 of the central device 4 calculates travel time and fuel consumption as the link cost.
This process is performed by the control unit 401 executing a computer program stored in the storage unit 404 of the central device 4.

[Calculation of travel time]
The travel time U of each link is an average value of travel time data of a large number of vehicles 5 passing through the link. That is, as shown in FIG. 2, for example, regarding an uplink line RS1 of a certain road RS, a link L1 sandwiched between an intersection J1 and an intersection J2 is considered, and the start point of this link L1 is P1, and the end point of the link L1 is P2. The travel time U of the link L1 is calculated as an average value of travel time data obtained from a large number of vehicles 5 passing through the points P1 and P2.

  In other words, the control unit 401 of the central device 4 always transmits the road device ID and the travel time data for each vehicle ID based on the time information S1 from each road device 3 that has communicated with many vehicles 5 between the road and vehicle. And the travel time U for each link is calculated by averaging the travel time data.

[Calculation of fuel consumption]
[Parameters required for calculation]
Since the central device 4 controls the traffic lights 1 at the respective intersections Ji (i = 1 to 12), the storage unit 404 of the central device 4 stores the signal cycle length C1 for the upstream intersection J1 during the cycle. The information on the length of each step and the lamp color of each signal lamp 1b in each step is stored.
The storage unit 404 of the central device 4 also stores the signal cycle length C2, the length of each step in the cycle, and the lamp color information of each signal lamp 1b in each step for the downstream intersection J2. ing.

  Further, the storage unit 404 of the central device 4 stores the offset A between the upstream intersection J1 and the downstream intersection J2 (the time difference between the start time of the first step of the downstream intersection J2 with respect to the start time of the first step of the upstream intersection J1). In addition, the standard travel time T from the point P1 to the point P2, the saturated traffic flow rate s at the point P2, and the number of vehicles m per unit queue length are stored as preset constants.

In addition, the control unit 401 of the central device 4 always acquires the queue length L in the direction of the link L1 at the downstream intersection J2 based on the time information S1 received from the roadside device 3.
Therefore, the control unit 401 of the central device 4 determines the green signal time G1 of the signal lamp 1b on the upstream side of the link L1 and the green signal time G2 of the signal lamp 1b on the downstream side based on the signal information of the upstream intersection J1 and the downstream intersection J2. Is calculated.

[Estimation of the number of stops]
Next, the control unit 401 of the central device 4 estimates the number of stops P of the vehicle 5 at the downstream intersection J2 based on the following estimation logic.
In this case, the number of stops P mathematically means an expected value of the number of times the vehicle 5 stops at the downstream intersection J2 of the link L1.

(1) When mL> sG2 In the above inequality, m × L on the left side means the number of queues at the downstream intersection J2, and s × G2 means the number of vehicles 5 at the downstream intersection J2. When the former (the number of queues) is larger than the latter (the number of queues), the queue L cannot be eliminated in one signal cycle at the downstream intersection J2 at the downstream point J2 of the link L1, and the vehicle 5 always stops at the downstream intersection J2.
Therefore, in this case, the control unit 401 of the central device 4 estimates the number of stops P of the vehicle 5 at the link L1 as a value obtained by dividing mL by sG2, that is, P = mL / sG2. This calculation formula represents the average value of the number of stops P due to signal waiting at the downstream intersection J2.

(2) When mL ≦ sG2 In this case, since the queue number mL is less than or equal to the earned number sG2, the queue L is eliminated in one signal cycle at the downstream intersection J2. For this reason, it is necessary to examine in more detail whether or not the vehicle 5 stops at the downstream intersection J2.
Therefore, the control unit 401 of the central device 4 classifies the signal cycle length C1 at the upstream intersection J1 and the signal cycle length C2 at the downstream intersection J2 according to whether the signal cycle length C1 is the same, and estimates the number of stops P in each case. To do.

i) When C1 = C2 In this case, the difference in the switching timing of the signal lamp 1b between the upstream intersection J1 and the downstream intersection J2 is constant in each cycle. presume.
FIG. 6 is a graph showing the relationship between the distance x between the intersections J1 and J2, the traveling time t, and the signal cycles C1 and C2 for explaining the method of estimating the number of stops P in this case. In FIG. 6, the horizontal axis indicates the distance x from the intersection J1 to the intersection J2, and the vertical axis indicates the time t during which the vehicle 5 travels the distance x. In FIG. 6, the double line indicates the red signal time, and the space between them indicates the green signal time.

As shown in FIG. 6, when the green signal start time at the upstream intersection J1 is t1, the green signal end time at the upstream intersection J1 is t1 + G1.
On the other hand, when the departure time of the point P1 (link start point) for the vehicle 5 to arrive at the point P2 (link end point) at the green signal start time of the downstream intersection J2 is t2, the departure time t2 is calculated by using the offset A and the link L1. Can be calculated using the standard travel time T.
Further, the departure time of the point P1 (link start point) for the vehicle 5 to arrive at the point P2 (link end point) at the green light end time of the downstream intersection J2 can be obtained by t2 + G2.

In this case, the control unit 401 of the central device 4 estimates the number of stops P of the vehicle 5 at the downstream intersection J2 by the following equation (1).
P = 1- [min (t1 + G1, t2 + G2) -max (t1, t2)] / G1 (1)
In the above formula (1), min () means to select the smaller one in parentheses, and max () means to select the larger one in parentheses.

  In the above equation (1), the second term on the right side means the probability (expected value) that the vehicle 5 that has passed the start point P1 of the link L1 in blue can pass the end point P2 of the link L1 in blue. The number of stops P defined in (1) means the probability (expected value) that the vehicle 5 that has departed from the point P1 while the downstream intersection J1 is in the green light meets the red signal at the downstream intersection J2 at the point P2. Become.

ii) When C1 ≠ C2 In this case, the difference in signal switching timing between the intersections J1 and J2 changes for each cycle, so the number of stops P is determined by the vehicle 5 arriving at the point P2 as a red signal at the downstream intersection J2. Probability of encountering.
Therefore, in this case, the control unit 401 of the central device 4 estimates the number of stops P by the following equation (2).
P = 1-G2 / C2 (2)
The calculation formula (2) represents the probability (expected value) that the vehicle 5 will reach the downstream intersection in red.

[Calculation formula of fuel consumption]
The control unit 401 of the central device 4 uses the travel time U, the travel distance D, and the stop count P between the points P1 and P2 to calculate the fuel consumption Q required to travel from the point P1 to the point P2. Calculated according to equation (3). The control unit 401 calculates the fuel consumption amount Q for each link.
Q = aU + bD + cP (3)

Here, the above formula (3) is substantially the same as the calculation formula described in the non-patent document 1 (the formula (8) of the reference 1), and in the formula (8) of the non-patent document 1 The third term on the right side is replaced with “cP”. Assuming that the standard traveling speed of the vehicle 5 is v, since the acceleration from 0 to v occurs once per stop, such replacement is possible.
According to the estimation model of Non-Patent Document 1 described above, the values of the coefficients a, b, and c in the above equation (3) are a = 0.3, b = 0.028, and c, respectively. = is a 0.056v ^2. However, the values of the coefficients a, b, and c are not limited to such numerical values.
In addition, the uplink information transmitted by the in-vehicle device 2 includes type distinction such as large vehicles, medium-sized vehicles and small vehicles, and type distinction such as gasoline vehicles and diesel vehicles, and the fuel consumption based on the above equation (3). Q may be calculated for each type distinction. In this case, different values are used for each type classification as the coefficients a, b, and c in the above equation (3).

[Providing link costs]
The control unit 401 of the central device 4 includes the calculated travel time U and fuel consumption Q for each link in the traffic information S2, and transmits the traffic information S2 from the communication unit 403 to each roadside device 3. The roadside device 3 that has received the link cost transmits the link cost including the travel time and the fuel consumption amount to the in-vehicle device 2 of the vehicle 5 having the corresponding vehicle ID (type distinction).

[Route search with in-vehicle devices]
The processing unit 209 of the in-vehicle device 2 that has received the link cost performs a route search by using the travel time U and the fuel consumption Q for each link as the link cost.
In other words, the processing unit 209 of the in-vehicle device 2 is an algorithm for solving the shortest path problem with a path that minimizes the link cost (total travel time ΣU or total fuel consumption ΣQ) from its departure place to the destination. A search is made based on a certain Dijkstra method or the like, and a route that can arrive at the destination in the shortest time or the minimum fuel is presented to the driver through the display unit 207 and the audio output unit 208.

As described above, according to the traffic signal control system (route search system) of the present embodiment, the control unit 401 of the central device 4 determines the number of stops P at which the vehicle 5 traveling on the link stops at the downstream intersection J2 of the link. Since the fuel consumption amount Q, which is one of the link costs, is calculated based on the estimated number of stops P, the fuel consumption amount Q closer to the actual state of vehicle travel in consideration of the fluctuation of the vehicle speed due to stop / start is calculated. Can be provided.
For this reason, in the in-vehicle device 2, the fuel consumption Q that requires the vehicle speed fluctuation characteristic can be adopted as the link cost, and the versatility of the route guidance system using the link cost can be improved.

[Other Embodiments]
In the above embodiment, the road device 3 is composed of a narrow area communication device such as an optical beacon. However, as the road device 3, a medium / wide area communication device 3A (see FIG. 2) may be used.
The communication device 3A includes a wireless LAN, WiMAX (World Interoperability for Microwave Access), a mobile phone, or the like, and can wirelessly communicate various types of information with the in-vehicle device 2 mounted on the vehicle 5 over a relatively wide range. .

In this case, since the passing position of the vehicle 5 (link start point P1 and end point P2) cannot be specified at the installation position of the roadside device 3A, the vehicle ID, time information, and position information of the vehicle 5 are obtained from the communication unit 204 of the in-vehicle device 2. The communication device 3A is transmitted in real time (for example, a cycle of 0.1 to 1.0 seconds), and the information is transmitted from each communication device 3A to the central device 4 so as to collect time information such as travel time data. do it.
In addition, in order to reduce the number of communications, the time information S1 and position information are stored in the storage unit in real time, and are transmitted together with the own vehicle ID every time a preset condition such as time and travel distance is satisfied. You may do it.

  Moreover, in the said embodiment, the link cost (travel time U and fuel consumption Q) for every link calculated in the central apparatus 4 which is an infrastructure side apparatus is provided to the vehicle-mounted apparatus 2, and this link cost is provided in this vehicle-mounted apparatus 2 side. However, the route search may be performed by the central device 4 that is the infrastructure side device, and the search result may be provided to the in-vehicle device 2. Further, the control unit 401 of the central device 4 on the infrastructure side performs the estimation up to the number of stops P and provides the result to the in-vehicle device 2, and the processing unit 209 of the in-vehicle device 2 is based on the acquired number of stops P. A link cost for each link may be calculated and a route search to the destination may be performed. In this case, of the components (estimating means and calculating means) of the link cost calculating device, the estimating means belongs to the infrastructure side device and the calculating means belongs to the in-vehicle device 2.

Further, the central device 4 is not limited to the case where the link cost (travel time U and fuel consumption Q) is calculated and provided, but a plurality of traffic signals 1 included in the LAN are separated from the control by the central device 4. The present invention can also be applied when calculating and providing a link cost in units.
In this case, the link cost (travel time U and fuel consumption Q) is calculated and provided not to the control unit 401 of the central apparatus 4 but to the control unit 101 of one terminal control apparatus 1a in the same control group. I will let you.

  The above-described embodiments are all illustrative and do not limit the scope of the present invention. The scope of the present invention is shown not by the above embodiment but by the scope of claims for patent, and includes modifications within the scope equivalent to the structure of the scope of claims for patent.

It is a schematic diagram which shows the outline | summary of a traffic signal control system (route search system). It is a schematic diagram which shows the outline | summary of a traffic signal. It is a block diagram which shows the structure of a central apparatus. It is a block diagram which shows the structure of a terminal control apparatus. It is a block diagram which shows the structure of a vehicle-mounted apparatus. It is a graph which shows the relationship between the distance between intersections, traveling time, and a signal cycle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Traffic signal apparatus 1a Terminal control apparatus 1b Signal lamp 101 Control part 102 Lamp drive part 103 Communication part 104 Storage part 105 Wireless communication part 2 In-vehicle apparatus 201 GPS processing part 202 Direction sensor 203 Vehicle speed acquisition part 204 Communication part (transmission means)
205 Storage Unit 206 Operation Unit 207 Display Unit 208 Audio Output Unit 209 Processing Unit 3 On-Road Device 4 Central Device (Link Cost Calculation Device)
401 Control unit (estimating means, calculating means)
402 Display Unit 403 Communication Unit 404 Storage Unit 405 Operation Unit 5 Vehicle Ji Intersection S1 Time Information S2 Traffic Information S3 Signal Control Command S4 Control Type Information

Claims (15)

A link cost calculation device for calculating a link cost of a link including an intersection,
Estimating means for estimating the number of stops at which a vehicle traveling on the link stops at a downstream intersection of the link , using signal information generated by the infrastructure side device ;
A link cost calculation apparatus comprising: a calculation unit that calculates the link cost based on the estimated number of stops.   The link cost calculation apparatus according to claim 1, wherein the estimation unit performs the process of estimating the number of stops based on the number of queues at the downstream intersection and the number of earnings at the downstream intersection.   3. The link cost calculation device according to claim 2, wherein the estimation unit performs the estimation process on the condition that the number of queues at the downstream intersection is larger than the number of earnings in one signal cycle at the downstream intersection. .   2. The link cost calculation device according to claim 1, wherein the estimation unit performs the estimation process of the number of stops based on a probability that a vehicle that has passed an upstream intersection of the link in blue can pass a downstream intersection of the link in blue. . The link cost calculation apparatus according to claim 4, wherein the estimation unit performs the process of estimating the number of stops based on the following equation (1).
P = 1- [min (t1 + G1, t2 + G2) -max (t1, t2)] / G1 (1)
However,
P: Number of stops
t1: Start time of green light at upstream intersection
t2: Departure time of the link start point for the vehicle to pass the link end point at the green light start time of the downstream intersection
G1: Green traffic time at upstream intersection
G2: Green traffic time at downstream intersection   The link cost calculation device according to claim 4 or 5, wherein the estimation means performs the estimation process on condition that a signal cycle length at the upstream intersection is the same as a signal cycle length at the downstream intersection.   The link cost calculation apparatus according to claim 1, wherein the estimation unit performs the estimation process of the number of stops based on a green signal time and a signal cycle length of the downstream intersection.   The link cost calculation apparatus according to claim 7, wherein the estimation unit performs the estimation process on condition that a signal cycle length at the upstream intersection is not the same as a signal cycle length at the downstream intersection.   9. The method according to claim 4, wherein the estimation unit performs the estimation process on the condition that the number of queues at the downstream intersection is equal to or less than the number of queues in one signal cycle at the downstream intersection. The link cost calculation device described. The link cost calculation device according to any one of claims 1 to 9,
A route guidance system comprising: a route search device that searches for a route from a departure point of the vehicle to a destination using the link cost calculated for each link. The infrastructure side device, and an in-vehicle device capable of communicating with the infrastructure side device,
The route guidance system according to claim 10, wherein the link cost calculation device is incorporated in the infrastructure side device, and the route search device is incorporated in the in-vehicle device. The infrastructure side device, and an in-vehicle device capable of communicating with the infrastructure side device,
The route guidance system according to claim 10, wherein both the link cost calculation device and the route search device are incorporated in the infrastructure side device. The infrastructure side device, and an in-vehicle device capable of communicating with the infrastructure side device,
The route guidance system according to claim 10, wherein the estimation unit of the link cost calculation device is incorporated in the infrastructure side device, and the calculation unit of the calculation device and the route search device are incorporated in the in-vehicle device. A computer program for causing a computer to execute processing for calculating a link cost of a link including an intersection,
Estimating the number of stops at which a vehicle traveling on the link stops at a downstream intersection of the link using signal information generated by the infrastructure side device ;
And calculating the link cost based on the estimated number of stops. A method for calculating a link cost of a link including an intersection with a link cost calculation device provided on the infrastructure side ,
Using the signal information generated by the infrastructure side device , estimating the number of stops at which a vehicle traveling on the link stops at a downstream intersection of the link, and calculating the link cost based on the estimated number of stops A characteristic link cost calculation method.

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