Traffic signal lamp control method based on road monitoring

Abstract

The invention discloses a traffic signal lamp control method based on road monitoring, and belongs to the technical field of signal control, and the method specifically comprises the steps: obtaining the road information of all traffic road sections, selecting any intersection, monitoring the congestion coefficients of lanes in all directions in the intersection, and determining the traffic information of all traffic road sections; if the congestion coefficient of the lane in any direction is greater than or equal to a preset threshold value, the lane in the direction is calibrated as a target lane; counting the total number of target lanes of the road junction, calculating a congestion coefficient mean value of the target lanes, calculating priority values W of all the road junctions, and sorting all the road junctions in the current traffic network according to a sequence of the priority values from large to small to generate a priority sequence; the congestion coefficients of adjacent upstream and downstream lanes in the corresponding directions of any target lane of each road junction are sequentially obtained, the green light passing time of the road junction is controlled, intelligent regulation and control of the traffic signal lamps are achieved, and therefore traffic pressure is effectively relieved.

Description

Technical Field

[0001] The present invention relates to the technical field of signal control, and in particular to a traffic signal light control method based on road monitoring. Background Art

[0002] Road monitoring system is an important part of modern urban traffic management. It collects and transmits traffic conditions in real time through monitoring equipment distributed at major intersections and key sections, so that the traffic management center can adjust traffic flow and handle traffic accidents in time. These systems can not only improve the modernization level of traffic management, but also play an important role in maintaining social security.

[0003] The control of existing traffic lights at intersections mainly considers the situation of vehicles on the entrance road, such as the speed of traffic on the entrance road, the road capacity, and vehicles queuing at the intersection. Although the consideration and control of these factors have improved the traffic conditions to a certain extent, due to the relatively single consideration of factors, it is easy to cause the transfer of congestion, and it is impossible to fundamentally solve the problem of vehicle congestion. In addition, the control of traffic lights at a road intersection is usually carried out in isolation. In other words, it is only controlled by considering the traffic conditions of the road intersection, without considering the road traffic conditions of the intersections adjacent to the road intersection. In today's urban traffic, the traffic conditions of each adjacent road intersection often affect each other. Therefore, the signal control effect is not ideal for alleviating vehicle congestion. Summary of the invention

[0004] The purpose of the present invention is to provide a traffic signal light control method based on road monitoring to solve the following technical problems:

[0005] The prior art only considers the traffic conditions of a single road intersection and performs local signal light control without considering the traffic conditions of the intersections adjacent to the road intersection. In today's urban traffic, the traffic conditions of adjacent road intersections often affect each other, so the actual adjustment effect is not ideal.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A traffic signal light control method based on road monitoring comprises the following steps:

[0008] S1, obtaining the intersection information of all traffic sections in the intelligent transportation network based on machine vision technology, wherein the intersection information includes the intersection entrance information and the intersection exit information, and both the intersection entrance and the intersection exit are signal light intersections;

[0009] S2, select any road intersection and monitor the congestion coefficients of all directional lanes in the road intersection. If the congestion coefficient of any directional lane is greater than or equal to a preset threshold, mark the directional lane as a target lane; count the total number of target lanes at the road intersection and calculate the average congestion coefficient of the target lanes, calculate the priority value W of all road intersections according to the average congestion coefficient and the number of target lanes, and sort all road intersections in the current traffic network in descending order according to the priority values ​​to generate a priority sequence D1, D2, ..., Dn;

[0010] S3, acquiring all target lanes at each intersection in turn according to the priority sequence, selecting any target lane and acquiring the second congestion coefficient of the corresponding lane at the adjacent upstream intersection and the third congestion coefficient of the corresponding lane at the adjacent downstream intersection of the target lane; and controlling the green light passage time at the intersection, the upstream intersection and the downstream intersection according to the acquired second and third congestion coefficients.

[0011] As a further solution of the present invention: in S2, the specific process of monitoring the congestion coefficient of lanes in any direction is:

[0012] S11, select a lane in any direction and take the end where the traffic light at the intersection is located as the starting point, and go in the opposite direction of the vehicle to the end where the traffic light at the upstream intersection is located as the end point to obtain the target road;

[0013] S12, obtaining road information of the target road, the road information including the maximum speed limit of the road, the number of lanes m, the total length of the road L, the road curvature R and the number of vehicles N, setting the safe distance between each vehicle to be l, obtaining the average length of the vehicle body and marking it as l1, determining the buffer section in the target road and obtaining the length of the buffer section S; calculating the maximum total number of vehicles that can be accommodated by the non-buffer section at the same time, recorded as the vehicle capacity, marked as Nmax, where:

[0014] Nmax=(LS) / (l1+l)*m;

[0015] S13, obtain all vehicles that have exited the buffer section during the time when the traffic light is green in the previous red-green cycle at the intersection, obtain the total time T1 for any vehicle to pass the target road and the time T2 for the vehicle to stay in the buffer section, calculate the driving time of the vehicle on the regular section (T1-T2), and thus obtain the average driving time T of several vehicles on the regular section; then calculate the traffic speed V based on the average time T, the length s of the buffer section and the total length L of the target road, where:

[0016] V = (LS) / T;

[0017] S14, calculating the congestion coefficient TCI according to the obtained target road traffic flow, vehicle capacity and traffic speed, where:

[0018] TCI = N*V / Nmax*(D+R*β);

[0019] D = N / m*(LS);

[0020] Wherein, N is the vehicle flow of the target road, β is the preset correction coefficient, D is the road density, and R is the curvature of the target road.

[0021] As a further solution of the present invention: In S12, the specific process of determining the buffer section is as follows:

[0022] The maximum speed limit v of the target road is obtained, and the time t consumed when a vehicle with a speed of v decelerates to 0 at a preset acceleration a is obtained; and the distance S traveled by the vehicle with a speed of v in the process of decelerating to a stop is calculated, starting from the end where the traffic light at the intersection is located, and selecting a section of length S from the road to be evaluated in the opposite direction of the vehicle's travel, which is recorded as a buffer section.

[0023] As a further solution of the present invention: in S2, the calculation process of the priority value W is:

[0024] W=N'e αTCI ';

[0025] Wherein, N' is the target number of lanes at the intersection, TCI' is the mean congestion coefficient of the target lanes, and α is the preset correction coefficient.

[0026] As a further solution of the present invention: In S3, the specific process of controlling the green light passage time is as follows:

[0027] Preset the timing change interval [Minh, Maxh] and obtain the green light passage time H of the current target lane, according to the calculation formula H'=H*1 / [(1+TCI-TCIa)+(1+TCI-TCIb)], where TCIa is the second congestion coefficient of the corresponding lane of the adjacent upstream intersection; TCIb is the third congestion coefficient of the corresponding lane of the adjacent downstream intersection; calculate the green light time adjustment amount H' of the current target lane, if H' is greater than Maxh, correct H' to Maxh; if H' is less than Minh, correct H' to Minh.

[0028] As a further solution of the present invention: if the absolute value of the difference between the second congestion coefficient and the congestion coefficient of the target lane is less than or equal to a preset threshold, the green light passage time of the downstream road intersection is controlled with the same time as the green light passage time of the target road.

[0029] As a further solution of the present invention: if the absolute value of the difference between the third congestion coefficient and the congestion coefficient of the target lane is less than or equal to a preset threshold, the green light passage time at the downstream road intersection is controlled with the same time as the green light passage time of the target road.

[0030] As a further solution of the present invention: if the absolute value of the difference between the congestion coefficient of the target lane at any intersection and the congestion coefficient of the corresponding lane at the adjacent upstream and downstream intersections is less than or equal to a preset threshold, and the priority values ​​of the adjacent upstream and downstream intersections of the intersection are greater than the priority value of the intersection, the green light passage times Ha and Hb of the adjacent upstream and downstream intersections are obtained respectively, and the time with the largest green light passage time is selected to control the green light passage time of the intersection.

[0031] Beneficial effects of the present invention:

[0032] The present invention acquires information of all road sections in a traffic network and selects any intersection to monitor the congestion coefficients of lanes in all directions, and then calculates a priority value based on the congestion coefficient and the number of lanes. Based on the priority value, the traffic pressure at all intersections in the road network can be accurately evaluated. It can be understood that the greater the traffic pressure, the more signal light adjustment control is needed to alleviate the congestion of the traffic network. A priority sequence is generated by sorting according to the priority value, and the adjustment order of all intersections is determined according to the priority sequence. The congestion coefficients of the upstream and downstream intersections adjacent to the target lane in any intersection are acquired. According to the acquired second and third congestion coefficients, the green light passage time at the intersection, the upstream intersection and the downstream intersection is controlled, thereby realizing intelligent regulation of traffic lights, thereby effectively alleviating traffic pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below in conjunction with the accompanying drawings.

[0034] Figure 1 The present invention is a flow chart of a traffic signal light control method based on road monitoring. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] See also Figure 1 As shown, the present invention is a traffic signal light control method based on road monitoring, comprising the following steps:

[0037] S1, obtaining road information of all traffic sections in the intelligent transportation network based on machine vision technology, wherein the road information includes a maximum speed limit, the number of lanes, the total length of the road, the curvature of the road, and the number of vehicles;

[0038] S2, select any road intersection and monitor the congestion coefficients of all directional lanes in the road intersection. If the congestion coefficient of any directional lane is greater than or equal to a preset threshold, mark the directional lane as a target lane; count the total number of target lanes at the road intersection and calculate the average congestion coefficient of the target lanes, calculate the priority value W of all road intersections according to the average congestion coefficient and the number of target lanes, and sort all road intersections in the current traffic network in descending order according to the priority values ​​to generate a priority sequence D1, D2, ..., Dn;

[0039] S3, acquiring all target lanes at each intersection in turn according to the priority sequence, selecting any target lane and acquiring the second congestion coefficient of the corresponding lane at the adjacent upstream intersection and the third congestion coefficient of the corresponding lane at the adjacent downstream intersection of the target lane; and controlling the green light passage time at the intersection, the upstream intersection and the downstream intersection according to the acquired second and third congestion coefficients.

[0040] The present invention acquires information of all road sections in a traffic network and selects any intersection to monitor the congestion coefficients of lanes in all directions, and then calculates a priority value based on the congestion coefficient and the number of lanes. Based on the priority value, the traffic pressure at all intersections in the road network can be accurately evaluated. It can be understood that the greater the traffic pressure, the more signal light adjustment control is needed to alleviate the congestion of the traffic network. A priority sequence is generated by sorting according to the priority value, and the adjustment order of all intersections is determined according to the priority sequence. The congestion coefficients of the upstream and downstream intersections adjacent to the target lane in any intersection are acquired. According to the acquired second and third congestion coefficients, the green light passage time at the intersection, the upstream intersection and the downstream intersection is controlled, thereby realizing intelligent regulation of traffic lights, thereby effectively alleviating traffic pressure.

[0041] It is worth noting that in the present invention, the road information of each road section in the traffic network is first obtained, and the congestion coefficient of any directional lane in each road intersection is obtained based on the road information. It can be understood that a road intersection is usually divided into a crossroads, a Y-shaped intersection and a multi-fork intersection, etc. The directional lanes of any road intersection can be determined according to the road type, and the congestion coefficient of the directional lanes of each road intersection is obtained. If the congestion coefficient of any directional lane is greater than or equal to a preset threshold, the directional lane is marked as a target lane. It can be understood that when the congestion coefficient reaches a certain threshold, it will affect the road traffic. Therefore, the number of target lanes at each road intersection is obtained and the mean congestion coefficient of the target lane is calculated. The priority values ​​of all road intersections are calculated based on the mean congestion coefficient and the number of target lanes. It can be understood that the larger the priority value, the better the road traffic. The more congested the intersection is, the greater the traffic pressure is. Therefore, it is necessary to control the signal lights at the intersection to alleviate the traffic pressure at the intersection. All target lanes at each intersection are obtained in turn according to the priority sequence. Any target lane is selected and the second congestion coefficient of the corresponding lane at the adjacent upstream intersection of the target lane and the third congestion coefficient of the corresponding lane at the adjacent downstream intersection are obtained. It can be understood that only adjusting the green light passage time at the current intersection can alleviate the traffic pressure at the current intersection, but it will affect the traffic pressure at the upstream and downstream intersections of the intersection, and may cause larger and wider traffic network congestion. Therefore, in the present invention, the green light passage time of the current intersection is adjusted by the second congestion coefficient of the corresponding lane at the adjacent upstream intersection of the target lane and the third congestion coefficient of the corresponding lane at the adjacent downstream intersection.

[0042] In a preferred situation of this embodiment, in S2, the specific process of monitoring the congestion coefficient of lanes in any direction is:

[0043] S11, select a lane in any direction and take the end where the traffic light at the intersection is located as the starting point, and go in the opposite direction of the vehicle to the end where the traffic light at the upstream intersection is located as the end point to obtain the target road;

[0044] S12, obtaining road information of the target road, the road information including the maximum speed limit of the road, the number of lanes m, the total length of the road L, the road curvature R and the number of vehicles N, setting the safe distance between each vehicle to be l, obtaining the average length of the vehicle body and marking it as l1, determining the buffer section in the target road and obtaining the length of the buffer section S; calculating the maximum total number of vehicles that can be accommodated by the non-buffer section at the same time, recorded as the vehicle capacity, marked as Nmax, where:

[0045] Nmax=(LS) / (l1+l)*m;

[0046] S13, obtain all vehicles that have exited the buffer section during the time when the traffic light is green in the previous red-green cycle at the intersection, obtain the total time T1 for any vehicle to pass the target road and the time T2 for the vehicle to stay in the buffer section, calculate the driving time of the vehicle on the regular section (T1-T2), and thus obtain the average driving time T of several vehicles on the regular section; then calculate the traffic speed V based on the average time T, the length s of the buffer section and the total length L of the target road, where:

[0047] V = (LS) / T;

[0048] S14, calculating the congestion coefficient TCI according to the obtained target road traffic flow, vehicle capacity and traffic speed, where:

[0049] TCI = N*V / Nmax*(D+R*β);

[0050] D = N / m*(LS);

[0051] Wherein, N is the vehicle flow of the target road, β is the preset correction coefficient, D is the road density, and R is the curvature of the target road.

[0052] The present invention evaluates congestion by combining vehicle capacity and traffic speed. Traffic capacity refers to the maximum number of vehicles that a road can carry within a period of time, while traffic speed refers to the average speed of vehicles passing through the road. When the traffic volume exceeds the vehicle capacity, the traffic speed will decrease, resulting in congestion. It can be understood that traffic lights on the road will affect the speed of road vehicles. Therefore, a buffer section is set and the total time T1 for any outgoing vehicle to pass the target road and the time T2 for the vehicle to stay in the buffer section are obtained. The driving time of the vehicle on the regular section is calculated, thereby obtaining the average driving time of several vehicles on the regular section. The actual driving speed of the vehicle on the current road is calculated based on the average time, and the congestion coefficient TCI of the actual target road is calculated based on the obtained target road traffic volume, vehicle capacity and traffic speed.

[0053] In another preferred situation of this embodiment, in S12, the specific process of determining the buffer section is:

[0054] The maximum speed limit v of the target road is obtained, and the time t consumed when a vehicle with a speed of v decelerates to 0 at a preset acceleration a is obtained; and the distance S traveled by the vehicle with a speed of v in the process of decelerating to a stop is calculated, starting from the end where the traffic light at the intersection is located, and selecting a section of length S from the road to be evaluated in the opposite direction of the vehicle's travel, which is recorded as a buffer section.

[0055] In another preferred situation of this embodiment, in S2, the calculation process of the priority value W is:

[0056] W=N'e αTCI ';

[0057] Wherein, N' is the target number of lanes at the intersection, TCI' is the mean congestion coefficient of the target lanes, and α is the preset correction coefficient.

[0058] In another preferred situation of this embodiment, in S3, the specific process of controlling the green light passage time is as follows:

[0059] Preset the timing change interval [Minh, Maxh] and obtain the green light passage time H of the current target lane, according to the calculation formula H'=H*1 / [(1+TCI-TCIa)+(1+TCI-TCIb)], where TCIa is the second congestion coefficient of the corresponding lane of the adjacent upstream intersection; TCIb is the third congestion coefficient of the corresponding lane of the adjacent downstream intersection; calculate the green light time adjustment amount H' of the current target lane, if H' is greater than Maxh, correct H' to Maxh; if H' is less than Minh, correct H' to Minh; correct the green light passage time of the current target lane to H+H'.

[0060] By correcting the upper and lower limits of H', we can ensure that the traffic light timing will not be unsafe or inefficient due to extreme calculation results, and avoid traffic safety hazards and inefficiency caused by too long green light time.

[0061] In another preferred situation of the present embodiment, if the absolute value of the difference between the second congestion coefficient and the congestion coefficient of the target lane is less than or equal to a preset threshold, the green light passage time at the upstream road intersection is controlled with the same time as the green light passage time of the target road.

[0062] It can be understood that if the absolute value of the difference between the second congestion coefficient and the congestion coefficient of the target lane is less than or equal to the preset threshold, it means that the congestion situation at the current intersection is not much different from the congestion situation at the upstream intersection. Therefore, the green light time of the downstream road is controlled at the same time as the green light time of the target road to ensure a smooth transition of traffic flow between adjacent intersections and avoid the generation of new congestion points at the intersection due to differences in green light time.

[0063] In another preferred situation of the present embodiment, if the absolute value of the difference between the third congestion coefficient and the congestion coefficient of the target lane is less than or equal to a preset threshold, the green light passage time at the downstream road intersection is controlled with the same time as the green light passage time of the target road.

[0064] It can be understood that if the absolute value of the difference between the third congestion coefficient and the congestion coefficient of the target lane is less than or equal to the preset threshold, it means that the congestion situation at the current intersection is not much different from the congestion situation at the downstream intersection. Therefore, the green light time of the downstream road is controlled at the same time as the green light time of the target road to ensure a smooth transition of traffic flow between adjacent intersections and avoid the generation of new congestion points at the intersection due to differences in green light time.

[0065] In another preferred situation of the present embodiment, if the absolute value of the difference between the congestion coefficient of the target lane of the current intersection and the congestion coefficient of the corresponding lane of the adjacent upstream and downstream intersections is less than or equal to a preset threshold, and the priorities of the adjacent upstream and downstream intersections are higher than the current intersection, the adjacent upstream green light passage time Ha is obtained and the green light passage time Ha is used as the green light passage time of the target lane of the current intersection.

[0066] It can be understood that the priorities of adjacent upstream and downstream intersections are higher than the current intersection, and the absolute values ​​of the differences between the congestion coefficients of the adjacent upstream and downstream intersections and the current road are less than the preset thresholds, which means that the congestion situation at the current intersection is not much different from that at the adjacent intersections. Therefore, the adjusted green light times of the adjacent roads are calculated respectively according to the priority value sequence order. It can be understood that since the congestion situation of the target lane at the current intersection is directly affected by the green light time of the adjacent upstream intersection, the adjusted green light time Ha of the adjacent upstream intersection is adopted and set as the green light time of the target lane of the current intersection to better regulate traffic flow and reduce congestion.

[0067] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A traffic light control method based on road monitoring, characterized in that: The following steps are involved: S1, obtaining road information of all traffic sections in the intelligent transportation network based on machine vision technology, wherein the road information includes a maximum speed limit, the number of lanes, the total length of the road, the curvature of the road, and the number of vehicles; S2, selecting any road intersection and monitoring the congestion coefficients of all directional lanes at the road intersection. If the congestion coefficient of any directional lane is greater than or equal to a preset threshold, the directional lane is marked as a target lane; Count the total number of target lanes at the intersection and calculate the average congestion coefficient of the target lanes. Calculate the priority value W of all intersections based on the average congestion coefficient and the number of target lanes. Then sort all intersections in the current traffic network in descending order according to the priority value to generate a priority sequence D1, D2, ..., Dn; S3, acquiring all target lanes at each intersection in turn according to the priority sequence, selecting any target lane and acquiring the second congestion coefficient of the corresponding lane at the adjacent upstream intersection and the third congestion coefficient of the corresponding lane at the adjacent downstream intersection of the target lane; and controlling the green light passage time at the intersection, the upstream intersection and the downstream intersection according to the acquired second and third congestion coefficients.

2. A traffic signal light control method based on road monitoring according to claim 1, characterized in that: In S2, the specific process of monitoring the congestion coefficient of lanes in any direction is: S11, select a lane in any direction and take the end where the traffic light at the intersection is located as the starting point, and go in the opposite direction of the vehicle to the end where the traffic light at the upstream intersection is located as the end point to obtain the target road; S12, obtaining road information of the target road, setting the safe distance between vehicles to l, obtaining the average length of the vehicle body and marking it as l1, determining a buffer section in the target road and obtaining the length S of the buffer section; The maximum number of vehicles that the non-buffered road section can accommodate at the same time is calculated and recorded as the vehicle capacity, marked as Nmax, where: Nmax=(LS) / (l1+l)*m; S13, obtain all vehicles that have exited the buffer section during the time when the traffic light is green in the previous red-green cycle at the intersection, obtain the total time T1 for any vehicle to pass the target road and the time T2 for the vehicle to stay in the buffer section, calculate the driving time of the vehicle on the regular section (T1-T2), and thus obtain the average driving time T of several vehicles on the regular section; then calculate the traffic speed V based on the average time T, the length S of the buffer section and the total length L of the target road, where: V = (LS) / T; S14, calculating the congestion coefficient TCI according to the obtained target road traffic flow, vehicle capacity and traffic speed, where: TCI = N*V / Nmax*(D+R*β); D = N / m*(LS); Wherein, N is the vehicle flow of the target road, β is the preset correction coefficient, D is the road density, R is the curvature of the target road, and m is the number of lanes.

3. A traffic signal light control method based on road monitoring according to claim 2, characterized in that: In S12, the specific process of determining the buffer section is as follows: The maximum speed limit v of the target road is obtained, and the time t consumed when a vehicle with a speed of v decelerates to 0 at a preset acceleration a is obtained, and the distance S traveled by the vehicle with a speed of v in the process of decelerating to a stop is calculated, and the end where the traffic light at the intersection is located is taken as the starting point, and a section of length S is selected from the target road in the opposite direction of the vehicle's travel and marked as a buffer section.

4. The traffic signal light control method based on road monitoring according to claim 1, characterized in that: In S2, the calculation process of the priority value W is: W=Move αTCI '; Wherein, N' is the target number of lanes at the intersection, TCI' is the mean congestion coefficient of the target lanes, and α is the preset correction coefficient.

5. The traffic signal light control method based on road monitoring according to claim 1, characterized in that: In S3, the specific process of controlling the green light passage time is as follows: Preset the timing change interval [Minh, Maxh] and obtain the green light passage time H of the current target lane, according to the calculation formula H'=H*1 / [(1+TCI-TCIa)+(1+TCI-TCIb)], where TCIa is the second congestion coefficient of the corresponding lane of the adjacent upstream intersection; TCIb is the third congestion coefficient of the corresponding lane of the adjacent downstream intersection; calculate the green light time adjustment amount H' of the current target lane, if H' is greater than Maxh, correct H' to Maxh; if H' is less than Minh, correct H' to Minh; correct the green light passage time of the current target lane to H+H.

6. The traffic signal light control method based on road monitoring according to claim 1, characterized in that: It also includes controlling the green light passage time of the upstream road intersection with the same time as the green light passage time of the target road if the absolute value of the difference between the second congestion coefficient and the congestion coefficient of the target lane is less than or equal to a preset threshold.

7. The traffic signal light control method based on road monitoring according to claim 1, characterized in that: It also includes controlling the green light passage time of the downstream road intersection with the same time as the green light passage time of the target road if the absolute value of the difference between the third congestion coefficient and the congestion coefficient of the target lane is less than or equal to a preset threshold.

8. The method for controlling a traffic signal light based on road monitoring according to claim 6, characterized in that: It also includes obtaining the adjacent upstream adjusted green light passage time Ha and using the green light passage time Ha as the green light passage time for the target lane of the current intersection if the absolute value of the difference between the congestion coefficient of the target lane of the current intersection and the congestion coefficient of the corresponding lane of the adjacent upstream and downstream intersections is less than or equal to a preset threshold, and the priorities of the adjacent upstream and downstream intersections are higher than the current intersection.

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