Driving assistance device

Abstract

This invention provides a driving assistance device that, when a vehicle is in a traffic jam, alleviates the congestion by facilitating lane changes by the vehicle itself or the vehicle in front, thereby suppressing provocative driving by drivers of following vehicles. The processor of the driving assistance device can control the vehicle based on information obtained from other vehicles and / or from sensors mounted on the vehicle itself. When the processor detects that the vehicle is in a traffic jam based on the information, if a first condition (determining that the vehicle's driving mode is one of the causes of the congestion) is met, and a second condition (determining that lane changes by the vehicle can alleviate the congestion) is met, the processor executes a first lane change facilitation process (promoting lane changes by the vehicle); if the second condition is not met, the processor executes a second lane change facilitation process (promoting lane changes by the vehicle in front).

Description

Technical Field

[0001] This invention relates to a driving assistance device that, under specified conditions, suppresses provocative driving by the driver of the following vehicle by facilitating lane changes by the vehicle itself or the vehicle in front. Background Technology

[0002] A driving assistance device is proposed, which has the following functions: based on information obtained from a driving recorder, a TOF sensor, an acceleration sensor, etc., it detects provocative driving by the driver of the following vehicle (the driver of the following vehicle intends to reduce the distance between the following vehicle and the own vehicle to a level that is more than necessary), and displays a warning to the following vehicle on a display device located at the rear of the own vehicle according to the degree of provocative driving detected (for example, see Patent Document 1 below).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2024-115745 Summary of the Invention

[0004] The aforementioned driver assistance device (warning display function) aims to suppress provocative driving by drivers of following vehicles. For example, when the vehicle is in a traffic jam, the likelihood of a driver of another vehicle (following behind) engaging in provocative driving increases. In this situation, even if the existing device warns the following vehicle, since the congestion is not alleviated (eliminated), the driver of the following vehicle may repeat the provocative driving as long as the vehicle continues to travel at a low speed.

[0005] One of the objectives of this invention is to provide a driving assistance device that, when a vehicle is in a traffic jam, alleviates the congestion by facilitating lane changes by the vehicle or the vehicle in front, thereby suppressing provocative driving by drivers of following vehicles.

[0006] In order to achieve the above objectives, the driving assistance device (1) of the present invention includes: a processor (10) configured to exchange various information with other vehicles (V1, V2) and configured to control the vehicle based on information obtained from the processor of the other vehicle and / or information obtained from the sensor (20) mounted on the vehicle.

[0007] The processor is configured such that, when it detects congestion in the lane in which the vehicle is traveling and the vehicle is within that congestion, if a first condition (Y1) is met, which determines that the vehicle's travel mode is one of the causes of the congestion, then...

[0008] If the second condition (Y2), which is used to determine that lane changing by vehicles can alleviate congestion, is met, then the process of promoting lane changing by vehicles, namely the first lane change promotion process, is executed.

[0009] If the second condition is not met, the process of promoting the lane change of the preceding vehicle, namely the second lane change promotion process, is executed.

[0010] As mentioned above, when a vehicle is in a congested traffic jam, the likelihood of drivers of following vehicles engaging in provocative driving increases. In such situations, sometimes changing lanes can alleviate the congestion. For example, if a vehicle is at the front of the congestion, changing lanes can help alleviate the congestion and thus suppress provocative driving by drivers behind. On the other hand, sometimes even changing lanes cannot alleviate the congestion. For instance, if the vehicle in front is traveling at a low speed, forcing the vehicle to travel at a low speed as well, changing lanes will not alleviate the congestion. In this case, the driver of the following vehicle (the vehicle immediately behind the vehicle before the lane change) may then engage in provocative driving against the vehicle in front (the vehicle directly in front of the vehicle before the lane change) after the lane change. In other words, even if the vehicle changes lanes, the effect of suppressing provocative driving is limited. Therefore, the processor of the driving assistance device according to the present invention performs processing to facilitate lane changing when it determines that the vehicle's driving mode is one of the causes of the congestion and that there is a high probability that the congestion can be alleviated by changing lanes. This increases the likelihood of congestion being alleviated and thus suppressing provocative driving by drivers of following vehicles. On the other hand, when the vehicle's driving mode is one of the causes of the congestion, but the probability of alleviating the congestion even if the vehicle changes lanes is low, it performs processing to request a lane change from the vehicle in front. This increases the likelihood of congestion being alleviated by the vehicle accelerating after the vehicle in front changes lanes, thus suppressing provocative driving by drivers of following vehicles.

[0011] In a driving assistance device according to one aspect of the present invention,

[0012] The processor is configured to determine that the first condition is met when the speed (sp2) of the following vehicle (V2) is higher than the speed (sp0) of the vehicle itself.

[0013] Therefore, the processor can relatively easily determine whether the first condition is met. Furthermore, the processor can obtain the vehicle's speed from the speed sensor, which is an onboard sensor. Also, the processor can obtain the speed of the following vehicle from radar (e.g., millimeter-wave radar), which is also an onboard sensor. Additionally, the processor can obtain the speed of the following vehicle from its processor (the following vehicle's speed sensor) via a wireless communication line.

[0014] In another aspect of the present invention, a driving assistance device,

[0015] The processor is configured to determine that the first condition is met when a following vehicle requests a lane change.

[0016] Therefore, the vehicle's processor can relatively easily determine whether the first condition is met. Furthermore, if the vehicle's processor is configured to determine whether the first condition is met based on the vehicle's speed and the speed of the following vehicle, and if, for some reason, the speeds of the vehicle and / or the following vehicle cannot be obtained, the determination can be made based on the presence or absence of a lane change request from the following vehicle.

[0017] In another aspect of the present invention, a driving assistance device,

[0018] The processor is configured to determine that the second condition is met when the speed (sp1) of the preceding vehicle (V1) is higher than the speed of the following vehicle.

[0019] Therefore, the vehicle's processor can more easily determine whether the second condition is met. Furthermore, the processor can obtain the vehicle's speed from the speed sensor, which is an onboard sensor. Also, the processor can obtain the speed of the vehicle in front from radar (e.g., millimeter-wave radar), which is also an onboard sensor. Additionally, the processor can obtain the speed of the vehicle in front from the processor (speed sensor of the vehicle in front) via a wireless communication line.

[0020] In another aspect of the present invention, a driving assistance device,

[0021] The processor is configured to determine that congestion has occurred in the lane and that the vehicle is in the congestion if the speed of the vehicle or the vehicle in front is lower than the lane's speed limit (splmt) and the difference (Δsp) exceeds a threshold (Δspth).

[0022] Therefore, the vehicle's processor can more easily determine whether the vehicle is in a traffic jam. Furthermore, the processor can obtain the vehicle's speed from the speed sensor, which is an onboard sensor. It can also obtain the speed of the vehicle ahead from radar (e.g., millimeter-wave radar), which is an onboard sensor. Additionally, the processor can obtain the speed of the vehicle ahead from its processor (the speed sensor of the vehicle ahead) via a wireless communication line. Furthermore, the processor can determine the speed limit for the lane in which the vehicle is traveling based on information obtained from a camera, which is an onboard sensor (an image of a speed limit sign or its analysis results). Additionally, the processor can obtain the speed limit for the current location from a designated storage medium (ROM installed in the vehicle) containing information indicating the speed limits for each lane (road). Attached Figure Description

[0023] Figure 1 This is a block diagram of a driving assistance device according to one embodiment of the present invention.

[0024] Figure 2 It is a top-down view showing the scene where the car is at the very front of the traffic jam.

[0025] Figure 3 This is a top-down view showing a scenario where vehicles are changing lanes to alleviate congestion.

[0026] Figure 4 This is a top-down view showing a scenario where a vehicle in front requests a lane change and the lane change is used to alleviate congestion.

[0027] Figure 5 This is a flowchart of the program executed by the CPU to implement the lane change assist function. Detailed Implementation

[0028] (roughly)

[0029] like Figure 1 As shown, a driving assistance device 1 according to one embodiment of the present invention is applied to a vehicle V0. The vehicle V0 (hereinafter referred to as "the vehicle") has an automatic driving function. The driving assistance device 1 has the following function (lane change promotion function): when the automatic driving function of the vehicle is disabled and the driver performs manual driving operation (manual driving mode), when the vehicle is in a traffic jam, it alleviates the congestion by promoting lane changes by the vehicle or the preceding vehicle V1 (a vehicle in the area in front of the vehicle), thereby suppressing provocative driving by the driver of the following vehicle V2 (a vehicle traveling directly behind the vehicle).

[0030] (Specific structure)

[0031] Next, the structure of the driving assistance device 1 will be described in detail. For example... Figure 1 As shown, the driving assistance device 1 includes an ECU 10, on-board sensors 20, and a steering device 30.

[0032] ECU 10 includes a microcomputer with CPU 10a, ROM 10b, RAM 10c, timer 10d, etc. ECU 10 is connected to another ECU via CAN (communication network). Furthermore, ECU 10 has a communication device 10e for connecting CPU 10a to the CPUs of other vehicles (front vehicle V1 and rear vehicle V2) via wireless communication lines. That is, CPU 10a can exchange various information with the CPUs of other vehicles.

[0033] The vehicle-mounted sensor 20 includes a peripheral sensor, namely a millimeter-wave radar 21, and a camera 22, for acquiring information related to targets located around the vehicle. Furthermore, the vehicle-mounted sensor 20 includes a vehicle sensor, namely a speed sensor 23, for acquiring information related to the vehicle's behavior. Additionally, the vehicle-mounted sensor 20 includes a navigation system 24.

[0034] The millimeter-wave radar 21 includes a transceiver unit and a signal processing unit (not shown). The transceiver unit radiates radio waves in the millimeter-wave band (hereinafter referred to as "millimeter waves") to the area surrounding the vehicle and receives millimeter waves (reflected waves) reflected by three-dimensional objects (such as the preceding vehicle V1, the following vehicle V2, and other vehicles traveling in adjacent lanes) located within the radiation range. The signal processing unit calculates the distance between the vehicle and the three-dimensional object, the speed of the three-dimensional object relative to the vehicle (relative speed), etc., based on the time from the transceiver unit's radiation of the millimeter waves to the reception of the reflected waves, the phase difference between the transmitted millimeter waves and the received reflected waves, and the attenuation level of the reflected waves, and provides the calculation results to the ECU 10.

[0035] Camera 22 includes imaging devices. These devices may incorporate imaging elements such as a charge-coupled device (CCD) or a CMOS image sensor (CIS). Each imaging device may be located, for example, on the front, right, left, and rear surfaces of the vehicle. The imaging devices acquire image data by capturing images of the vehicle's surrounding area at a predetermined frame rate. Camera 22 also includes an image analysis device. The image analysis device sequentially acquires image data from each imaging device. It analyzes the acquired image data to obtain information related to targets located around the vehicle. For example, the image analysis device identifies the area occupied by other vehicles in the image and other images, obtaining the shape and size of the area occupied by other vehicles as one type of target information. Furthermore, the image analysis device identifies images of the left and right boundary lines BL and BR that divide the lane L0 where the vehicle is traveling and the adjacent lane L1, and other images, acquiring the positions of the boundary lines BL and BR (e.g., the coordinates of the endpoints (the endpoints closer to the vehicle and the endpoints further away from the vehicle) in the direction of extension of the boundary lines BL and BR in the image) as one type of target information. The image analysis device also acquires the curvature (curve radius) of lane L0 based on the shape of the boundary lines BL and BR in the image as one type of target information. Additionally, the image analysis device identifies road signs (speed limit signs) and acquires the current speed limit (splmt) as one type of target information, based on the identification result. The image analysis device provides the acquired target information as boundary line information (target information) to the ECU 10.

[0036] Speed ​​sensor 23 detects the rotational speed (wheel speed) of each wheel and calculates the vehicle's speed sp0 (measured value) based on the wheel speed. Speed ​​sensor 23 provides this calculation result to ECU 10.

[0037] The navigation system 24 acquires GPS signals from multiple satellites and uses these signals to determine the vehicle's current position (latitude and longitude). Furthermore, the navigation system 24 possesses map information. This map information includes information related to road structure, such as the number of lanes constituting the road, information distinguishing between permitted and prohibited lane-changing areas, etc. The map information may also include the speed limit for each lane.

[0038] The steering system 30 has the function of automatically adjusting the rotation angle position (steering angle θ) of the steering wheel SW (automatic steering function). As components for implementing this function, the steering system 30 includes a steering ECU and a steering mechanism. The steering mechanism includes a linkage mechanism connecting the steering wheel SW and the steering wheel. The steering system 30 also includes an actuator (e.g., an electric motor) that drives the steering mechanism to change the rotation angle position (steering angle θ) of the steering wheel SW, and a steering angle sensor that acquires the steering angle θ. Under specified conditions, the ECU 10 determines a target value θt of the steering angle θ based on various information acquired from the on-board sensors 20. For example, the ECU 10 calculates (updates) the target value θt sequentially in a manner that moves the vehicle from lane L0 (lane change) to lane L1 adjacent to lane L0. The steering ECU acquires the target value θt from the ECU 10 and controls the actuator to make the value output from the steering angle sensor consistent with the target value θt.

[0039] (Lane change assist function)

[0040] Based on information obtained from the onboard sensors 20, ECU 10 sequentially determines whether "congestion has occurred in lane L0 and whether the vehicle is within that congestion." Specifically, ECU 10 sequentially determines whether the following condition X is met. Furthermore, the vehicle being at the forefront of the congestion is also included in the state where the vehicle is within the congestion.

[0041] Condition X… The average speed of the vehicle sp0 over a recent period of time is lower than the speed limit splmt of lane L0, and the difference Δsp exceeds the threshold Δspth.

[0042] If condition X is met, ECU 10 determines that there is congestion in lane L0 and the vehicle is located within that congestion. Additionally, ECU 10 can obtain the speed limit (splmt) for lane L0 (current location) from camera 22. If the speed limit (splmt) is included in the map information of navigation system 24, ECU 10 can obtain the speed limit (splmt) for the current location from navigation system 24.

[0043] Typically, when a vehicle is in a traffic jam (if condition X is met), the relatively low speed of the vehicle is sometimes one of the causes of the congestion. In this situation, the likelihood of the driver of the following vehicle V2 engaging in provocative driving (an act intended to reduce the distance to the following vehicle beyond what is necessary) increases. Therefore, when condition X is met, ECU 10 determines whether condition Y1 (the first condition of the present invention) is met.

[0044] Condition Y1... The speed of the vehicle sp0 is lower than the speed sp2 of the vehicle V2 behind it.

[0045] If condition Y1 is met, ECU 10 determines that the vehicle's driving mode is one of the reasons for congestion. Furthermore, ECU 10 can obtain the speed sp2 of the following vehicle V2 from its CPU via a wireless communication line. ECU 10 can also obtain the speed sp2 based on information obtained from millimeter-wave radar 21, camera 22, and speed sensor 23. Moreover, if ECU 10 receives a request to change lanes from the following vehicle V2 via a wireless communication line, it can determine that condition Y1 is met.

[0046] When a vehicle is determined to be in a congested area and its driving mode is one of the causes of the congestion (if both condition X and condition Y1 are met), sometimes changing lanes can alleviate the congestion. On the other hand, sometimes even if a vehicle changes lanes, the congestion is hardly alleviated.

[0047] Therefore, ECU10 determines whether the following condition Y2 (the second condition of the present invention) is met.

[0048] Condition Y2... The speed of the vehicle sp0 is lower than the speed sp1 of the vehicle in front V1.

[0049] When condition Y2 is met, the likelihood of the vehicle's driving mode being the cause of congestion is higher than that of the preceding vehicle V1. Therefore, when condition Y2 is met, ECU 10 determines that the congestion is alleviated by the vehicle changing lanes (the degree of congestion is improved compared to the vehicle maintaining its current driving mode). Furthermore, ECU 10 can obtain the speed sp1 of the preceding vehicle V1 from its CPU via a wireless communication line. ECU 10 can also obtain the speed sp1 based on information from millimeter-wave radar 21, camera 22, and speed sensor 23. When the preceding vehicle V1 is not present (when it is too far away to be detected (communication is impossible)), ECU 10 determines that condition Y2 is met.

[0050] If condition Y2 is determined to be met, ECU10 determines whether the vehicle can change lanes. Specifically, ECU10 determines whether conditions Z1 and Z2 are met based on information obtained from millimeter-wave radar 21, camera 22, and navigation system 24.

[0051] Z1... There exists a lane L1 adjacent to the lane L0 in which the vehicle is currently traveling, and lane changes from lane L0 to lane L1 are permitted.

[0052] Z2… In lane L1, there are no three-dimensional objects (other vehicles, pedestrians, etc.) in the designated area to the side, in front of and behind the vehicle.

[0053] If conditions Z1 and Z2 are met, ECU 10 determines that the vehicle is capable of changing lanes. In this case, ECU 10 controls the vehicle to facilitate the lane change (lane change facilitation process). Specifically, ECU 10 causes the image display device (or another display device) of navigation system 24 to display an image indicating a lane change request to the driver, and causes the audio device of navigation system 24 to play a prescribed voice. Then, if the driver performs the operation of promising the lane change, ECU 10 controls steering device 30 to move the vehicle from lane L0 to lane L1.

[0054] On the other hand, if condition Y2 is not met (sp0 > sp1), since the preceding vehicle V1 is traveling at a low speed, the driver of the vehicle may have to drive at a relatively low speed. Then, in this situation, even if the vehicle changes lanes, as long as the preceding vehicle V1 continues to travel at its current speed (sp1), the congestion will hardly be alleviated. Therefore, in this case, ECU10 sends a lane change request to the ECU of the preceding vehicle V1 via a wireless communication line (lane change facilitation processing). Thus, after the preceding vehicle V1 changes lanes, the vehicle accelerates to alleviate the congestion.

[0055] Next, refer to Figure 5 The program PR1 executed by the CPU 10a (hereinafter referred to as "CPU") to realize the above-mentioned function (lane change assist function) of the driving assistance device 1 will be described. The ECU 10 executes the program PR1 at a predetermined cycle when the ignition switch of the vehicle is in the on state.

[0056] (Program PR1)

[0057] The CPU starts executing program PR1 from step 100 and proceeds to step 101.

[0058] In step 101, the CPU determines whether the vehicle is in a traffic jam (whether condition X is met). If the CPU determines that the vehicle is in a traffic jam (101: Yes), it proceeds to step 102. On the other hand, if the CPU does not determine that the vehicle is in a traffic jam (101: No), it proceeds to step 107.

[0059] In step 102, the CPU determines whether the vehicle's driving mode is one of the causes of congestion (whether condition Y1 is met). If the CPU determines that the vehicle's driving mode is one of the causes of congestion (102: Yes), it proceeds to step 103. On the other hand, if the CPU does not determine that the vehicle's driving mode is one of the causes of congestion (102: No), it proceeds to step 107.

[0060] In step 103, the CPU determines whether changing lanes by the vehicle can alleviate congestion (whether condition Y2 is met). If the CPU determines that changing lanes by the vehicle can alleviate congestion (103: Yes), it proceeds to step 104. On the other hand, if the CPU does not determine that changing lanes by the vehicle can alleviate congestion (103: No), it proceeds to step 106.

[0061] In step 104, the CPU determines whether the vehicle can change lanes (whether conditions Z1 and Z2 are met). If the CPU determines that the vehicle can change lanes (104: Yes), it proceeds to step 105. On the other hand, if the CPU does not determine that the vehicle can change lanes (104: No), it proceeds to step 107.

[0062] In step 105, the CPU performs processing to facilitate lane changing for the vehicle. Specifically, the CPU controls the image display device and audio device to provide the driver with the prescribed images and voice prompts for facilitating lane changing. Furthermore, the CPU controls the steering device 30 to move the vehicle from its current lane L0 to lane L1. Next, the CPU proceeds to step 107.

[0063] In step 106, the CPU performs the process of facilitating the lane change of the preceding vehicle V1. That is, the CPU sends a lane change request to the CPU of the preceding vehicle V1 via a wireless communication line. Then, the CPU proceeds to step 107.

[0064] In step 107, the CPU terminates the execution of program PR1.

[0065] (Effect)

[0066] As mentioned above, when a vehicle is in a congested traffic jam, the likelihood of the driver of the following vehicle (V2) engaging in provocative driving increases. In this situation, sometimes changing lanes can alleviate the congestion. For example, if a vehicle is at the front of the congestion, changing lanes can alleviate the congestion and thus suppress provocative driving by the driver of the following vehicle (V2). On the other hand, sometimes even changing lanes cannot alleviate the congestion. For example, if the preceding vehicle (V1) is traveling at a low speed, forcing the vehicle to also travel at a low speed, changing lanes will not alleviate the congestion. In this case, the driver of the following vehicle (V2) (the vehicle immediately following the vehicle before the lane change) might engage in provocative driving against the preceding vehicle (V1) (the vehicle directly in front of the vehicle before the lane change) after the vehicle has changed lanes. That is, even if the vehicle changes lanes, the effect of suppressing provocative driving is limited. Therefore, in this embodiment, the ECU10 of the driving assistance device 1 determines that the vehicle's driving mode is one of the causes of the congestion and that there is a high probability that the congestion can be alleviated by changing lanes. This increases the likelihood of the driver of the following vehicle V2 engaging in provocative driving. On the other hand, if the vehicle's driving mode is one of the causes of the congestion, but the probability of alleviating the congestion even if the vehicle changes lanes is low, it executes a request for a lane change from the preceding vehicle V1. This increases the likelihood of the vehicle accelerating after the preceding vehicle V1 changes lanes, thereby reducing the likelihood of the driver of the following vehicle engaging provocative driving.

[0067] (Variation Example 1)

[0068] ECU10 can obtain the speed sp1 of the preceding vehicle V1 sequentially based on the information obtained from the vehicle sensor 20. If the average speed sp1 over a certain period of time is lower than the lane L0 speed limit splmt and the difference Δsp exceeds the threshold Δspth, then condition X is determined to be met.

[0069] (Variation Example 2)

[0070] ECU 10 can perform automatic speed adjustment processing, which controls the vehicle's drive system to ensure that the vehicle's speed sp0 matches a pre-set upper limit value sp0max. When performing automatic speed adjustment processing, if a preceding vehicle V1 is present and its speed sp1 is lower than the upper limit value sp0max, ECU 10 controls the vehicle's drive system and / or braking system to reduce speed sp0 to below speed sp1, rather than ensuring that the vehicle's speed sp0 matches the upper limit value sp0max. This maintains a distance between the preceding vehicle V1 and the vehicle that exceeds a predetermined value. When performing this automatic speed adjustment processing, ECU 10 can determine that condition X is met if the current value of the vehicle's speed sp0 is lower than the set upper limit value sp0max and the difference is below a threshold (or if the duration of this state exceeds the threshold).

[0071] (Variation Example 3)

[0072] When the speed of the vehicle (sp0) is lower than the speed (sp2) of the following vehicle (V2) and the difference (Δsp02) exceeds the threshold (Δsp02th), the ECU 10 determines that condition Y2 is met. Here, if each vehicle (e.g., the vehicle and the following vehicle (V2) can select a driving mode (a setting related to speed changes or speed limits for vehicles with manual driving operations), the ECU 10 of the vehicle can determine the value assigned to the threshold (Δsp02th) based on the driving mode of each vehicle. That is, the ECU 10 of the vehicle obtains the driving mode of the following vehicle (V2) from its ECU via a wireless communication line. Then, the ECU 10 of the vehicle determines the threshold (Δsp02th) assigned to condition Y2 based on both its own driving mode and the driving mode of the following vehicle (V2). For example, if the driving modes of the vehicle and the following vehicle (V2) are the same, the ECU 10 of the vehicle assigns a standard value to the threshold (Δsp02th). On the other hand, if the ECU10 of the vehicle selects "ECO mode" (a mode intended to improve fuel efficiency by driving the vehicle at a relatively slow speed) and the vehicle V2 selects "Sport mode" (a mode intended to drive the vehicle at a relatively high speed), it will assign a value smaller than the standard value to the threshold Δsp02th.

[0073] (Variation Example 4)

[0074] If the number N of other vehicles located immediately behind the vehicle and within a designated area R extending along lane L0 exceeds a threshold Nth, the ECU 10 can determine that condition X is met. Furthermore, the ECU 10 can receive the current positions (latitude and longitude) of other vehicles via wireless communication lines from their ECUs and obtain the number N of other vehicles within the designated area R based on this information. Alternatively, the ECU 10 can obtain congestion information from sensors installed on the road or from a server computer installed in road management facilities.

[0075] Symbol Explanation

[0076] 1-Driver assistance device, 10-ECU, 20-Vehicle sensors, 30-Steering device.

Claims

1. A driving assistance device comprising: a processor configured to exchange various information with another vehicle, and configured to control the vehicle based on information obtained from said other vehicle and / or information obtained from sensors mounted on the vehicle. The driving assistance device is characterized in that... The processor is configured such that, when it detects congestion in the lane in which the vehicle is traveling and the vehicle is within that congestion, and a first condition is met to determine that the vehicle's driving mode is one of the causes of the congestion, the processor will... If the second condition, which is used to determine that lane changing by vehicles can alleviate congestion, is met, then the process of promoting lane changing by vehicles, namely the first lane change promotion process, is executed. If the second condition is not met, the process of promoting the lane change of the preceding vehicle, namely the second lane change promotion process, is executed.

2. The driving assistance device according to claim 1, characterized in that, The processor is configured to determine that the first condition is met when the speed of the following vehicle is higher than that of the following vehicle.

3. The driving assistance device according to claim 1 or 2, characterized in that, The processor is configured to determine that the first condition is met when a following vehicle requests a lane change.

4. The driving assistance device according to claim 1, characterized in that, The processor is configured to determine that the second condition is met when the speed of the vehicle in front is higher than the speed of the vehicle itself.

5. The driving assistance device according to claim 1, characterized in that, The processor is configured to determine that a traffic jam has occurred in the lane and that the vehicle is in the traffic jam if the speed of the vehicle or the vehicle in front is lower than the speed limit of the lane and the difference exceeds a threshold.

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