Vehicle control device, vehicle control method, and program

Abstract

To inhibit unnecessary acceleration when a vehicle exits from a roundabout.SOLUTION: There is provided a vehicle control device that controls traveling of a vehicle at a roundabout in which a plurality of connected roads is connected to a circular road. The vehicle control device: acquires a traveling route of the vehicle including an exit road that is a connected road to which the vehicle is to exit from the circular road; acquires speed limits of the circular road and the exit road; calculates a target vehicle speed when the vehicle exits to the exit road from the circular road on the basis of the speed limits; calculates an acceleration necessary period or an acceleration necessary distance necessary for accelerating the vehicle to the target vehicle speed on the basis of current vehicle speed of the vehicle traveling on the circular road and the target vehicle speed; and starts acceleration control of accelerating the vehicle at predetermined acceleration when the calculated acceleration necessary period or acceleration necessary distance satisfies a predetermined start condition.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle control device, a vehicle control method, and a program. [Background technology]

[0002] For example, Patent Document 1 discloses a technology in which, in a vehicle equipped with a control device capable of performing adaptive cruise control (ACC), the speed of the vehicle is kept substantially constant between entering a roundabout (traffic circle) and changing direction to exit the roundabout, while the vehicle is accelerated while exiting the roundabout. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-088161 Summary of the Invention

[0004] The technology described in Patent Document 1 determines whether a vehicle is exiting a roundabout based on driving dynamics quantities (yaw rate and steering angle). Therefore, for example, if a vehicle changes lanes while traveling within a roundabout, it may erroneously determine that the vehicle is exiting the roundabout, which could result in unnecessary acceleration. Furthermore, the technology described in Patent Document 1 uses the target vehicle speed set by the ACC as the acceleration target. Therefore, if it erroneously determines that the vehicle will exit the roundabout too early, the vehicle may accelerate beyond the speed limit within the roundabout.

[0005] The present disclosure has been made to solve the above-mentioned problem, and aims to effectively suppress unnecessary acceleration when a vehicle exits a roundabout.

[0006] The vehicle control device of the present disclosure includes: A vehicle control device that controls vehicle travel at a roundabout where a plurality of connecting roads are connected to a circular road, Acquire a travel route for the vehicle that includes the loop road and an exit road that is a connecting road that is planned to exit from the loop road among the plurality of connecting roads; Obtaining the speed limits of the circular road and the exit road; calculating a target vehicle speed when the vehicle exits the loop road onto the exit road based on the speed limit; calculating a required acceleration time or required acceleration distance required to accelerate the vehicle to the target speed based on a current vehicle speed of the vehicle traveling on the loop road and the target vehicle speed; When the calculated required acceleration time or required acceleration distance satisfies a predetermined start condition, acceleration control is started to accelerate the vehicle at a predetermined acceleration rate. It is characterized by: [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a hardware configuration of a vehicle according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a software configuration of the control device according to the present embodiment. [Figure 3] FIG. 4 is a schematic diagram illustrating acceleration control according to the present embodiment. [Figure 4] 4 is a flowchart illustrating a routine for processing acceleration control according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, a vehicle control device according to this embodiment will be described with reference to the drawings.

[0009] [Hardware configuration] 1 is a schematic diagram showing the hardware configuration of a vehicle VH according to this embodiment. Hereinafter, the vehicle VH may also be referred to as the host vehicle when it is necessary to distinguish it from other vehicles.

[0010] The vehicle VH has an ECU (Electronic Control Unit) 10. The ECU 10 includes a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, and an interface device 14. The CPU 11 is a processor that executes various programs stored in the ROM 12. The ROM 12 is a non-volatile memory that stores data and the like required for the CPU 11 to execute the various programs. The RAM 13 is a volatile memory that provides a working area into which the various programs are expanded when the CPU 11 executes them. The interface device 14 is a communication device for communicating with external devices.

[0011] The ECU 10 is a central device that performs driving assistance such as ACC. Driving assistance is a concept that includes autonomous driving. The ECU 10 is communicably connected to a drive unit 20, a steering unit 21, a braking unit 22, an internal sensor unit 30, an external sensor unit 40, a position information acquisition unit 60, a map database 70, a communication unit 80, and the like.

[0012] The drive device 20 generates a drive force to be transmitted to the drive wheels of the vehicle VH. Examples of the drive device 20 include an electric motor and an engine. In this embodiment, the vehicle VH may be a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a fuel cell electric vehicle (FCEV), an electric vehicle (BEV), or an engine vehicle. The steering device 21 applies a steering force to the wheels of the vehicle VH. The braking device 22 applies a braking force to the wheels of the vehicle VH.

[0013] The internal sensor device 30 is a group of sensors that acquire the state of the vehicle VH. The internal sensor device 30 includes a vehicle speed sensor 31, an accelerator sensor 32, a brake sensor 33, a steering angle sensor 34, a yaw rate sensor 35, an acceleration sensor 36, and the like.

[0014] The vehicle speed sensor 31 detects the traveling speed (vehicle speed Vs) of the vehicle VH. The accelerator sensor 32 detects the amount of operation of an accelerator pedal (not shown) by the driver. The brake sensor 33 detects the amount of operation of a brake pedal (not shown) by the driver. The steering angle sensor 34 detects the rotation angle (steering angle) of a steering wheel or steering shaft (not shown). The yaw rate sensor 35 detects the yaw rate of the vehicle VH. The acceleration sensor 36 detects the acceleration of the vehicle VH. The internal sensor device 30 transmits the state of the vehicle VH detected by each sensor 31 to 36 to the ECU 10 at a predetermined interval.

[0015] The external sensor device 40 is a type of sensor that recognizes target information related to targets around the vehicle VH. The external sensor device 40 includes a radar sensor 41, a camera sensor 42, etc. Examples of the target information include surrounding vehicles, white lines on the road, road signs, etc.

[0016] The radar sensor 41 detects targets present around the vehicle VH. The radar sensor 41 includes a millimeter-wave radar and / or a lidar. The millimeter-wave radar emits millimeter-wave radio waves and receives millimeter waves reflected by targets present within the emission range. The millimeter-wave radar acquires the relative distance, relative speed, etc. between the vehicle VH and the target based on the phase difference between the transmitted millimeter waves and the received reflected waves, the attenuation level of the reflected waves, and the time from transmitting the millimeter waves to receiving the reflected waves. The lidar sequentially scans pulsed laser light with a wavelength shorter than millimeter waves in multiple directions and receives the reflected light reflected by the target to acquire the shape of targets detected around the vehicle VH, as well as the relative distance, relative speed, etc. between the vehicle VH and the target.

[0017] The camera sensor 42 photographs the surroundings of the vehicle VH and processes the photographed image data to acquire target information about the surroundings of the vehicle VH. The camera sensor 42 may be, for example, a digital camera having an imaging element such as a CMOS or CCD. The target information is information that indicates the type of target detected around the vehicle VH, the relative distance between the vehicle VH and the target, the relative speed, etc. The type of target may be recognized, for example, by machine learning such as pattern matching.

[0018] The external sensor device 40 repeatedly transmits the acquired target information to the ECU 10 every time a predetermined time elapses. Note that the external sensor device 40 does not necessarily have to include both the radar sensor 41 and the camera sensor 42, and may include, for example, only the radar sensor 41 or only the camera sensor 42.

[0019] The position information acquisition device 60 acquires current position information of the vehicle VH. For example, a GPS (Global Positioning System) or a GNSS (Global Navigation Satellite System) provided in a navigation system (not shown) can be used as the position information acquisition device 60. The position information acquisition device 60 transmits the acquired current position information of the vehicle VH to the ECU 10 at a predetermined interval.

[0020] The map database 70 is a database of map information and is stored in a storage device (hard disk, flash memory, etc.) provided in the vehicle VH. The map information includes the locations of road intersections, etc. The map database 70 may be stored in an external server that can communicate with the vehicle VH. In this case, the vehicle VH can obtain the map information from the external server via the communication device 80.

[0021] The communication device 80 performs V2X communication. Specifically, the communication device 80 performs V2I (Vehicle to Infrastructure) communication between the host vehicle VH and infrastructure. The communication device 80 can acquire information about the surroundings of the host vehicle VH through V2X communication. The surrounding information includes, for example, the positions of intersections. The communication device 80 transmits the acquired surrounding information to the ECU 10 at a predetermined interval.

[0022] [Software configuration] FIG. 2 is a schematic diagram showing the software configuration of the control device according to this embodiment.

[0023] 2, the ECU 10 includes, as functional elements, an ACC control unit 100, a roundabout travel determination unit 110, an exit road determination unit 120, a speed limit acquisition unit 130, an acceleration control unit 140, etc. Each of these functional elements 100 to 140 is realized by the CPU 11 of the ECU 10 reading a program stored in the ROM 12 into the RAM 13 and executing it. Note that all or part of the functional elements 100 to 140 may be provided in another ECU separate from the ECU 10, or in an information processing device in a facility (such as a management center) that can communicate with the vehicle VH.

[0024] The ACC control unit 100 executes ACC based on a set vehicle speed or a set inter-vehicle distance. ACC is well known, so a brief explanation will be given below. ACC includes two types of control: constant speed cruise control and follow-up cruise control. Constant speed cruise control is control that causes the vehicle VH to cruise at a constant speed according to a set vehicle speed. Follow-up cruise control is control that causes the host vehicle VH to follow a preceding vehicle traveling ahead of the host vehicle VH so that the inter-vehicle distance between the host vehicle VH and the preceding vehicle becomes the set inter-vehicle distance.

[0025] The ACC control unit 100 detects a preceding vehicle to be followed ahead of the host vehicle VH based on the detection results of the external sensor device 40. If there is no preceding vehicle to be followed, the ACC control unit 100 executes constant speed cruise control. In this case, the ACC control unit 100 controls the operation of the drive unit 20 and the brake unit 22 based on a target acceleration calculated from the deviation between the vehicle speed Vs and a set vehicle speed. The vehicle speed Vs may be obtained based on the detection results of the vehicle speed sensor 31. On the other hand, if there is a preceding vehicle to be followed ahead of the host vehicle VH, the ACC control unit 100 executes follow-up cruise control. In this case, the ACC control unit 100 controls the operation of the drive unit 20 and the brake unit 22 based on a target acceleration calculated from the deviation between the actual inter-vehicle distance and the set inter-vehicle distance. The inter-vehicle distance between the host vehicle VH and the preceding vehicle may be obtained based on the detection results of the external sensor device 40.

[0026] The roundabout travel determination unit 110 determines whether the vehicle VH is traveling through a roundabout while the ACC control unit 100 is executing ACC. Here, a roundabout refers to an intersection where multiple roads are connected to a circular road, and is also called a roundabout or a traffic circle. Hereinafter, a road connected to a circular road will be referred to as a "connecting road." The roundabout travel determination unit 110 determines whether the vehicle VH is traveling through the circular road of a roundabout when the map information in the map database 70 is available and the travel route has been set by the navigation system. A state in which map information is available means a state in which the position information acquisition device 60 can at least acquire the current position information of the vehicle VH (for example, a state in which the vehicle VH is not traveling in a place where it cannot receive GPS signals, such as inside a tunnel).

[0027] The roundabout travel determination unit 110 determines that the vehicle VH is traveling on the circular road of the roundabout if a roundabout is present on the travel route set by the navigation system and the current position information of the vehicle VH acquired by the position information acquisition device 60 approximately matches the position information of the roundabout acquired based on the map information in the map database 70. Note that the position information of the roundabout may be acquired based on infrastructure information received by the communication device 80 through V2I communication. Furthermore, if the external sensor device 40 recognizes a road sign or the like indicating a roundabout, it may determine whether the vehicle VH is traveling on the circular road of the roundabout based on the recognition result.

[0028] The exit road determination unit 120 determines which of the multiple connecting roads the vehicle VH plans to use to exit the loop road. Specifically, the exit connecting road determination unit 120 determines the connecting road the vehicle VH plans to use to exit based on the driving route set by the navigation system. Note that the technology disclosed herein does not exclude determining the connecting road the vehicle VH plans to use to exit based on driver operation information, including the blinking of turn signals, etc.

[0029] The speed limit acquisition unit 130 acquires the speed limit of the circular road of the roundabout through which the vehicle VH is traveling (hereinafter referred to as the circular road speed limit V R ) and the speed limit of the connecting road where the vehicle VH is planning to exit the loop road (hereinafter referred to as the post-exit speed limit V Lim Specifically, the speed limit acquisition unit 130 acquires the circular road speed limit V R And the speed limit after exiting is V Lim is acquired based on the map information in the map database 70. R And the speed limit after exiting is V Lim may be acquired based on infrastructure information received by the communication device 80 through V2I communication. In addition, when the external sensor device 40 recognizes a road sign or the like indicating an upper speed limit, the circular road speed limit V may be acquired based on the recognition result. R and the speed limit after exit V Lim may be obtained.

[0030] In this embodiment, when the vehicle VH enters the circular road of the roundabout, the ACC control unit 100 determines whether the set vehicle speed of the ACC is greater than the circular road speed limit V R , the ACC control unit 100 executes deceleration control to decelerate the vehicle VH. When the vehicle VH is caused to exit from the circular road of the roundabout to the connecting road, the ACC control unit 100 executes deceleration control to decelerate the vehicle VH. Lim is the circular road speed limit V R If the acceleration control unit 140 determines that the acceleration is greater than the predetermined acceleration, the acceleration control unit 140 executes acceleration control to accelerate the vehicle VH. The acceleration control executed by the acceleration control unit 140 will be described in detail below.

[0031] [Acceleration Control] The acceleration control unit 140 detects that the vehicle VH is traveling on the circular road of the roundabout when there is no preceding vehicle ahead of the vehicle VH that is the target of tracking by the ACC and the post-exit speed limit V Lim is the circular road speed limit V R If the difference is larger than , acceleration control is executed to accelerate the vehicle VH before the vehicle VH exits the loop road. FIG. 3 is a schematic diagram illustrating acceleration control according to this embodiment. In FIG. 3, symbol R1 indicates the loop road on which the vehicle VH is traveling, and symbol R2 indicates the connecting road from which the vehicle VH plans to exit. Symbol X indicates the connection between the loop road R1 and the connecting road R2, i.e., the exit.

[0032] When the vehicle VH enters the loop road R1 (see time t0 in FIG. 3), the acceleration control unit 140 sets the target vehicle speed VH at the exit X, which is the target vehicle speed when the vehicle VH reaches the exit X. target As an example, the acceleration control unit 140 calculates the circular road speed limit V R and post-exit speed limit V Lim The minimum function (MinV target (V R , V Lim )) based on the exit target vehicle speed V target The acceleration control unit 140 calculates the exit target vehicle speed V target When the vehicle VH is accelerated from the current vehicle speed Vs at a predetermined acceleration A, the exit target vehicle speed V targetThe time required to accelerate to the exit target vehicle speed V (hereinafter referred to as the required acceleration time Tr) is calculated. target and the current vehicle speed Vs, divided by the acceleration A (Tr = (V target After calculating the required acceleration time Tr, the acceleration control unit 140 accelerates the vehicle VH from the current vehicle speed Vs to the exit target vehicle speed V target The distance required for acceleration (hereinafter referred to as the required acceleration distance Dr) is calculated based on the target vehicle speed V target and the current vehicle speed Vs, multiplied by the required acceleration time Tr (Dr = (V target -Vs) × Tr).

[0033] The acceleration control unit 140 calculates the time it takes for the vehicle VH to reach the exit X if it travels at the current vehicle speed Vs (hereinafter referred to as the predicted arrival time T) and the distance it takes for the vehicle VH to reach the exit X from its current position (hereinafter referred to as the predicted arrival distance D). The current vehicle speed Vs of the vehicle VH may be obtained based on the detection result of the vehicle speed sensor 31, and the current position of the vehicle VH may be obtained based on the detection result of the position information acquisition device 60. The position information of the exit X may be obtained based on the map information in the map database 70, or may be obtained based on the detection result of the external environment sensor device 40.

[0034] When acceleration start conditions that satisfy the following first and second conditions are met, the acceleration control unit 140 starts acceleration control to accelerate the vehicle VH at a predetermined acceleration A (see time t1 in FIG. 3). First condition: The required acceleration time Tr is equal to or greater than the predicted arrival time T (Tr≧T). Second condition: The required acceleration distance Dr is equal to or less than the predicted arrival distance D (Dr≦D).

[0035] After starting acceleration control when the first condition and the second condition are satisfied, the acceleration control unit 140 determines whether the vehicle speed Vs of the vehicle VH reaches the exit target vehicle speed V targetWhen the acceleration control unit 140 ends the acceleration control, the vehicle returns to normal ACC by the ACC control unit 100.

[0036] 4 is a flowchart illustrating a routine for processing acceleration control executed by the CPU 11 of the ECU 10. This routine is started by execution of ACC.

[0037] In step S100, the ECU 10 determines whether the map information in the map database 70 is available. If the map information is available (Yes), the ECU 10 proceeds to the process of step S110. On the other hand, if the map information is not available (No), the ECU 10 returns from this routine.

[0038] In step S110, the ECU 10 determines whether a travel route has been set by the navigation system. If a travel route has been set by the navigation system (Yes), the ECU 10 proceeds to the processing of step S120. On the other hand, if a travel route has not been set by the navigation system (No), the ECU 10 returns from this routine. Note that the processing of steps S100 and S110 may be performed in any order and may be performed simultaneously.

[0039] In step S120, the ECU 10 determines whether the vehicle VH is traveling on the circular road of a roundabout. Specifically, if a circular road exists on the travel route set by the navigation system and the current position information of the vehicle VH acquired by the position information acquisition device 60 substantially matches the position information of the circular road acquired based on the map information in the map database 70, the ECU 10 determines that the vehicle VH is traveling on the circular road of the roundabout. If the ECU 10 determines that the vehicle VH is traveling on the circular road of the roundabout (Yes), the ECU 10 proceeds to processing in step S130. On the other hand, if the ECU 10 determines that the vehicle VH is not traveling on the circular road of the roundabout (No), the ECU 10 returns from this routine.

[0040] In step S130, the ECU 10 determines whether or not a preceding vehicle to be followed is present ahead of the host vehicle VH based on the detection result of the external sensor device 40. If no preceding vehicle is present (No), the ECU 10 proceeds to processing in step S140. On the other hand, if a preceding vehicle is present (Yes), the ECU 10 returns from this routine.

[0041] In step S140, the ECU 10 determines the connecting road through which the vehicle VH is scheduled to exit the loop road. Then, in step S145, the ECU 10 determines the loop road speed limit V R and the speed limit after exiting V Lim and get.

[0042] In step S150, the ECU 10 determines whether the circular road speed limit V R and post-exit speed limit V Lim Based on the minimum function of target Next, in step S160, the exit target vehicle speed V is calculated when the vehicle VH is accelerated from the current vehicle speed Vs at a predetermined acceleration A. target Further, in step S165, the ECU 10 calculates the required acceleration time Tr required to accelerate the vehicle VH from the current vehicle speed Vs to the exit target vehicle speed V target The acceleration distance Dr required to accelerate to

[0043] In step S170, the ECU 10 determines whether a first condition is satisfied, that is, the required acceleration time Tr is equal to or greater than the predicted arrival time T. If the first condition is satisfied (Yes), the ECU 10 proceeds to the process of step S175. On the other hand, if the first condition is not satisfied (No), the ECU 10 returns to the process of step S170.

[0044] In step S175, the ECU 10 determines whether a second condition is met, that is, the acceleration required distance Dr is equal to or less than the predicted arrival distance D. If the second condition is met (Yes), the ECU 10 proceeds to the process of step S180. On the other hand, if the second condition is not met (No), the ECU 10 returns to the process of step S150.

[0045] In step S180, the ECU 10 executes acceleration control to accelerate the vehicle VH at a predetermined acceleration A. Next, in step S185, the ECU 10 determines whether or not an end condition for the acceleration control is met. If the end condition is met (Yes), specifically, if the vehicle speed Vs of the vehicle VH reaches the exit target vehicle speed V target If the acceleration limit reaches 0 or if the driver performs an override operation by depressing the accelerator pedal, the ECU 10 proceeds to the process of step S190, terminates the acceleration control, and returns to this routine. That is, the ECU 10 returns to normal ACC. On the other hand, if the termination condition is not met (No), the ECU 10 returns to the process of step S180 and continues the acceleration control.

[0046] According to the present embodiment described above in detail, the ECU 10 determines the connecting road R2 on which the vehicle VH plans to exit the loop road R1 based on the travel route set by the navigation system. This prevents erroneous determinations (e.g., erroneously determining a lane change as an exit) that would occur if the determination of exit from the loop road R1 were based on the yaw rate, steering angle, etc., and also effectively prevents unnecessary acceleration of the vehicle VH on the loop road R1.

[0047] In addition, the ECU 10 determines the speed limit of the connecting road R2 from which the vehicle VH is planning to exit (post-exit speed limit VLim ) based on the map information of the map database 70, and the acquired post-exit speed limit V Lim Based on the exit target vehicle speed V target Then, the vehicle speed Vs of the vehicle VH is set to the exit target vehicle speed V target The system is configured to calculate the required acceleration time Tr and required acceleration distance Dr required to reach the target speed, and determine the optimal start timing of acceleration control based on the calculated required acceleration time Tr and required acceleration distance Dr. As a result, when the vehicle VH exits the loop road R1, it is possible to achieve quick acceleration that matches the driver's sense, while effectively preventing the vehicle VH from accelerating beyond the speed limit within the loop road R1, thereby reliably improving safety.

[0048] Although the vehicle control device, vehicle control method, and program according to the present embodiment have been described above, the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the scope of the present disclosure. For example, although the above embodiment has been described using ACC as an example, the technology of the present disclosure can also be applied to a vehicle that can only perform cruise control, or an autonomous vehicle that performs some or all of the driving operations automatically.

Claims

1. A vehicle control device that controls vehicle travel at a roundabout where a plurality of connecting roads are connected to a circular road, Acquire a travel route for the vehicle that includes the loop road and an exit road that is a connecting road that is planned to exit from the loop road among the plurality of connecting roads; Obtaining the speed limits of the circular road and the exit road; calculating a target vehicle speed when the vehicle exits the loop road onto the exit road based on the speed limit; calculating a required acceleration time or required acceleration distance required to accelerate the vehicle to the target speed based on a current vehicle speed of the vehicle traveling on the loop road and the target vehicle speed; When the calculated required acceleration time or required acceleration distance satisfies a predetermined start condition, acceleration control is started to accelerate the vehicle at a predetermined acceleration rate. A vehicle control device comprising:

2. The vehicle control device according to claim 1, calculating a predicted arrival time for the vehicle to reach an exit section that is a connection section between the loop road and the exit road, and a predicted arrival distance for the vehicle to reach the exit section; The start condition is met when the required acceleration time is equal to or greater than the predicted arrival time, or when the required acceleration distance is equal to or less than the predicted arrival distance. A vehicle control device comprising:

3. The vehicle control device according to claim 1, The target speed is calculated using a minimum function that adopts the smaller of the speed limits of the loop road and the exit road. A vehicle control device comprising:

4. A vehicle control method for controlling vehicle travel at a roundabout where a plurality of connecting roads are connected to a circular road, comprising: Acquire a travel route for the vehicle that includes the loop road and an exit road that is a connecting road that is planned to exit from the loop road among the plurality of connecting roads; Obtaining the speed limits of the circular road and the exit road; calculating a target vehicle speed when the vehicle exits the loop road onto the exit road based on the speed limit; calculating a required acceleration time or required acceleration distance required to accelerate the vehicle to the target speed based on a current vehicle speed of the vehicle traveling on the loop road and the target vehicle speed; When the calculated required acceleration time or required acceleration distance satisfies a predetermined start condition, acceleration control is started to accelerate the vehicle at a predetermined acceleration rate. A vehicle control method comprising:

5. A computer of a vehicle control device that controls vehicle travel at a roundabout where a plurality of connecting roads are connected to a circular road, Acquire a travel route for the vehicle that includes the loop road and an exit road that is a connecting road that is planned to exit from the loop road among the plurality of connecting roads; Obtaining the speed limits of the circular road and the exit road; calculating a target vehicle speed when the vehicle exits the loop road onto the exit road based on the speed limit; calculating a required acceleration time or required acceleration distance required to accelerate the vehicle to the target speed based on a current vehicle speed of the vehicle traveling on the loop road and the target vehicle speed; When the calculated required acceleration time or required acceleration distance satisfies a predetermined start condition, a process is executed to start acceleration control for accelerating the vehicle at a predetermined acceleration. A program characterized by:

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