Design of Adaptive Signal Control for Straight-Right Lane in Connected Environment and Its Application Method

Abstract

The present invention discloses a design and application method for an adaptive signal control of a straight-right lane in a connected environment, including designing the straight-right lane markings; collecting vehicle arrival information through the connected environment by a signal control center; optimizing the traffic distribution of straight-through vehicles by minimizing a cost function and calculating the dynamic queue length of the straight-through lane; according to the queue length of the straight-through lane, adaptively flashing a prompt signal on the straight-right lane signal indicating that the signal is about to change; changing the signal of the straight-right lane to allow straight-through vehicles to pass; the method of the present invention can effectively improve the safety of the straight-right lane and the efficiency of right-turning vehicles while ensuring the safety of the straight-through lane and the passing efficiency of straight-through vehicles, and has practical engineering application value.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent traffic control, and specifically refers to an adaptive signal control design and its application method for a straight-right lane in a connected environment. Background Art

[0002] As an important part of the urban road network, signalized intersections often cause interruptions to traffic flow and safety hazards due to the control of traffic lights. Traffic managers have developed various traffic management measures to improve the safety and traffic efficiency of intersections. Among many applied technologies, the connected environment has great potential for solving the safety and efficiency problems of intersections. In the connected environment, vehicles transmit the state information of the vehicle-road (such as speed and position) to the traffic signal control center through vehicle-road communication technology, and the traffic signal control center optimizes the signal timing to reduce vehicle delays and conflicts.

[0003] The straight-right lane is a common lane form at intersections. The straight-right lane design allows straight-going vehicles and right-turning vehicles to travel simultaneously. However, due to the different right-of-way priorities of straight-going vehicles and right-turning vehicles at intersections, during the red-light phase, the queuing straight-going vehicles on the straight-right lane often block the passage of right-turning vehicles. To solve this problem, traffic management departments usually adopt measures such as adding dedicated right-turn lanes or right-turn channelization facilities. However, this method is difficult to implement at intersections facing land resource shortages. In addition, some researchers have pointed out that by setting a pre-signal to convert the straight-right lane into a dedicated right-turn lane during the red-light period, this method often leads to too many queuing vehicles on the straight lane, increasing the conflict risk. In addition, the setting of pre-signals also requires additional costs. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the above background art, and develop an adaptive signal control design strategy for the straight-right lane in a connected environment to improve the safety and traffic efficiency of intersection traffic.

[0005] To achieve the above purpose, the technical solution provided by the present invention is: an adaptive signal control design and its application method for a straight-right lane in a connected environment, including the following:

[0006] Step 1, design the straight-right lane markings;

[0007] Step 2, use the signal control center to collect vehicle arrival information through the connected environment;

[0008] Step 3, optimize the straight-through traffic distribution by minimizing the cost function and calculate the dynamic queue length of the straight lane;

[0009] Step 4, according to the queue length of the straight lane, adaptively flash the straight-right lane signal light to indicate that the signal is about to change;

[0010] Step 5: The signal light in the straight-right lane changes, allowing straight-through vehicles to pass.

[0011] Preferably, in Step 1, the straight-right lane marking is located within the straight-right lane, the right-turn lane marking is a normal marking, and the arrow position of the straight-through lane marking is regarded as a broken-solid line, indicating that straight-through vehicles can only pass in the straight-right lane under certain conditions.

[0012] Preferably, the certain conditions include: when the signal light turns red, if the dynamic queue length in the straight-through lane is not full, only right-turn vehicles are allowed to pass in the straight-right lane; when the dynamic queue length is full, straight-through vehicles can queue or pass in the straight-right lane.

[0013] Preferably, in Step 2, the collection of vehicle arrival information includes: in a connected environment, the vehicle conveys its arrival information to the signal control center at the intersection through vehicle-road communication, including the proportion of upcoming straight-through vehicles and right-turn vehicles during the red light period.

[0014] Preferably, Step 3 specifically includes the following steps:

[0015] Step 3.1: Construct a cost function, including safety and efficiency. Among them, safety considers the risk of increased conflicts in the straight-through lane when the allocated straight-through vehicles queue in the straight-through lane, while efficiency considers the reduced queuing time for right-turn vehicles during the red light period. The calculation formula is as follows:

[0016]

[0017] Where RC l is the cost function of lane 1, l = 1 represents the straight-through lane, and l = 2 represents the straight-right lane; α and β respectively represent the weight coefficients of safety and efficiency, both taking 0.5 here; SPF l represents the traffic conflict in lane 1. The calculation formula is as follows:

[0018] SPF = V 0.65 exp(-2.046 + 0.0122Q);

[0019] V is the traffic volume per cycle, obtained through the arrival information of connected vehicles; Q represents the queue length, which is the straight-through traffic allocation result in the following formula and is calculated as follows:

[0020] L que,m = n s1,m + n sr1,m -(n s2,m + n sr2,m );

[0021] Where L que,m is the number of queuing vehicles, then the queue length Q = Lque，m × vehicle length. In addition, when Q represents the queue length of the straight - right lane, it is set to 0 to maximize the safety weight of the straight - through lane, that is, Q2 = 0;

[0022] represents the average waiting time of the queuing vehicles on Lane 1, which consists of two parts: the average queuing waiting time t AQWT and the starting - to - leave time The average queuing waiting time refers to the time when the vehicle waits stationary for the red light during the red - light period; the starting - to - leave time represents the time difference from when the vehicle starts to move until it leaves the intersection. The calculation formula is as follows:

[0023]

[0024] where h is the saturated headway, and n l is the number of queuing vehicles on Lane 1, which is the result of traffic assignment, that is:

[0025] n1 = n s1,m + n sr1,m = 6 + 3 = 9, n2 = n s2,m + n sr2,m = 0;

[0026] In addition, when the straight - through vehicles can queue on the straight - right lane, it will affect the subsequent right - turning vehicles. Therefore, when l = 2, this influence needs to be considered, that is:

[0027]

[0028] where r r represents the proportion of right - turning vehicles on the straight - right lane, which is 0.6; thus, it can be obtained that:

[0029]

[0030] Step 3.2: Taking the minimum cost of traffic assignment as the goal, use the ant - colony algorithm to optimize the traffic assignment result of the straight - through vehicles within one cycle, and obtain the queue length of the straight - through lane calculated according to the traffic assignment;

[0031] Step 3.3: According to the vehicle queuing situation on the straight - through lane, use this as the basis for adjusting the signal lights of the straight - right lane.

[0032] Preferably, in Step 4, the adaptive straight - right lane signal light includes: the straight - right lane signal light can update the dynamic queue length according to the traffic state of each cycle, perform optimal traffic indication, and achieve adaptive control.

[0033] The advantages of the present invention compared with the prior art are as follows: According to the designed indication markings adapted to the signal lamp control and the vehicle-road information about to arrive collected by the intersection signal control center through vehicle-road communication technology, the straight-through vehicle traffic distribution is optimized by minimizing the cost function, and the dynamic queue length of the straight-through lane is calculated; according to the queue length of the straight-through lane, the signal lamp of the straight-right lane blinks adaptively to prompt that the signal is about to change; the signal lamp of the straight-right lane changes to allow the straight-through vehicles to pass; the method of the present invention can effectively improve the safety of the straight-right lane and the efficiency of the right-turning vehicles while ensuring the safety of the straight-through lane and the passing efficiency of the straight-through vehicles, and has practical engineering application value. Brief Description of the Drawings

[0034] Figure 1 It is the flowchart of the method in Embodiment 1 of the present invention;

[0035] Figure 2 It is the design of the straight-right lane markings in Embodiment 1 of the present invention;

[0036] Figure 3 It is the straight-through vehicle traffic distribution in Embodiment 1 of the present invention;

[0037] Figure 4 It is the optimization of traffic distribution by the ant colony algorithm in Embodiment 1 of the present invention;

[0038] Figure 5 It is the schematic diagram of traffic operation in Embodiment 1 of the present invention. Detailed Embodiment

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations.

[0040] Embodiment 1:

[0041] This embodiment discloses a straight-right lane adaptive signal control design and its application method in a networked environment, including the following steps:

[0042] 1) Design of straight-right lane markings:

[0043] For the selected signal intersection with a straight-right lane, the markings as shown in Figure 2 are designed on the straight-right lane.

[0044] 2) The signal control center collects vehicle arrival information through the networked environment:

[0045] When the intersection is about to turn red, the vehicle uses vehicle-road communication technology to transmit the arrival information to the intersection signal control center. The signal control center obtains the straight-through vehicles that are about to arrive (such as n sr = 3, n s = 6) and the right-turn ratio (such as r r = 0.6).

[0046] 3) Optimize the straight-through vehicle traffic distribution by minimizing the cost function and calculate the dynamic queue length of the straight-through lane:

[0047] Step 3.1: Construct a cost function that includes safety and efficiency. Safety considers the risk of increased conflicts in the straight-through lane when the allocated straight-through vehicles queue up, while efficiency considers the reduced queuing time for right-turning vehicles during the red light. The calculation formula is as follows:

[0048]

[0049] where RC l is the cost function of lane 1, l = 1 represents the straight-through lane, and l = 2 represents the straight-right lane; α and β represent the weight coefficients of safety and efficiency, both of which are taken as 0.5 here; SPF l represents the traffic conflict in lane 1; the calculation formula is as follows:

[0050] SPF = V 0.65 exp(-2.046 + 0.0122Q)

[0051] V is the traffic volume per cycle, obtained from the arrival information of connected vehicles. It is assumed that an average of 11 vehicles pass through in one cycle; Q represents the queue length, which is the result of the straight-through vehicle traffic distribution in the following formula. The distribution diagram is shown in Figure 4 , and the calculation is as follows:

[0052] L que,m = n s1,m + n sr1,m -(n s2,m + n sr2,m )

[0053] where L que,m is the number of queuing vehicles. To obtain the queue length Q, multiply the obtained number of queuing vehicles by the vehicle length, which is assumed to be 6m in this article. For example, if the initial allocation is n s1,m = 6, n sr1,m = 3, n sr1,m = 0, n sr2,m = 0, then Q1 = (6 + 3 - 0 - 0) × 6 = 45m; in addition, when Q represents the queue length of the straight-right lane, it is set to 0 to ensure the maximum safety weight of the straight-through lane, that is, Q2 = 0.

[0054] Indicates the average waiting time of queuing vehicles on Lane 1, which consists of two parts: the average queuing waiting time t AQWT and the starting departure time The average queuing waiting time refers to the time when the vehicle waits stationary for the red light during the red light period. Here, take t AQWT = t red / 2, assuming the red light duration t red = 60s; and the starting departure time represents the time difference from when the vehicle starts to move until it leaves the intersection. The calculation formula is as follows:

[0055]

[0056] where h is the saturated headway time, assumed to be 3s here, and n l is the number of queuing vehicles on Lane 1, which is the result of traffic assignment, i.e., n1 = n s1,m + n sr1,m = 6 + 3 = 9, n2 = n s2,m + n sr2,m = 0. In addition, when straight-going vehicles can queue on the straight-right lane, it will affect the subsequent right-turning vehicles. Therefore, when l = 2, this influence needs to be considered, that is

[0057]

[0058] where r r represents the proportion of right-turning vehicles on the straight-right lane, which is 0.6. Therefore, it can be obtained that

[0059]

[0060] When l = 1, When l = 2,

[0061] Step 3.2. Aiming at the minimum cost of traffic assignment, use the ant colony algorithm (as Figure 4 shown) to optimize the traffic assignment result of straight-going vehicles within one cycle, and is the queuing length of the straight lane calculated according to traffic assignment. Such as the optimization result within the above cycle

[0062] n s1,m = 5, n sr1,m = 2, n sr1,m = 1, n sr2,m = 1, and the queuing length is (5 + 2 - 1 - 1) * 6 = 30m.

[0063] Step 3.3. According to the queuing situation of vehicles on the straight lane, use this as the basis for adjusting the signal lights of the straight-right lane. In this case, when the queuing length of the straight lane reaches 30m, straight-going vehicles can pass on the straight-right lane.

[0064] 4) According to the queue length of the straight lane, adaptively flash the prompt signal of the straight-right lane signal light to indicate that the signal is about to change: when the queue length of the straight lane is greater than or equal to 30m, the straight-right lane signal light flashes to prompt that the straight-going vehicles can enter the straight-right lane soon; this control process can update the dynamic queue length according to the traffic status of each cycle, provide the optimal traffic indication, and achieve the adaptive control function.

[0065] 5) The straight-right lane signal light changes, prompting that the straight-going vehicles can queue or pass in the straight-right lane, and the operation process is as Figure 5 shown. Figure 5 (a) and (b) in the figure are general traffic conditions, at this time the straight-right lane is shared by straight-going vehicles and right-turning vehicles; when the signal light turns red, if the dynamic queue length (30m) on the straight lane is not full ( Figure 5 (c) in the figure), only right-turning vehicles are allowed to pass in the straight-right lane, and when the dynamic queue length is full ( Figure 5 (d) in the figure), straight-going vehicles can queue or pass in the straight-right lane.

[0066] The above describes the present invention and its implementation manners. Such description is not restrictive, and only one of the implementation manners of the present invention is shown in the drawings. The actual structure is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and design similar structural manners and embodiments without creative work without departing from the spirit of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. An adaptive signal control design and its application method for the straight-right lane in a connected environment, characterized in that The following are included: Step 1: Design the straight - right lane markings; Step 2: Use the signal control center to collect vehicle arrival information through the connected environment; Step 3: Optimize the straight - through vehicle traffic distribution by minimizing the cost function based on the ant colony algorithm, and calculate the dynamic queue length of the straight - through lane; Specifically, it includes the following steps: Step 3.1: Construct a cost function, including safety and efficiency. Among them, safety considers the risk of increased conflicts in the straight - through lane when the allocated straight - through vehicles queue up on the straight - through lane, and efficiency considers the reduced queuing time for right - turn vehicles during the red light period. Its calculation formula is as follows: Among them, RC l is the cost function of lane 1, where l = 1 represents the straight lane and l = 2 represents the straight-right lane; α and β respectively represent the weight coefficients of safety and efficiency, both of which are taken as 0.5 here; SPF l represents the traffic conflict of lane 1; its calculation formula is as follows: SPF = V 0.65 exp(-2.046 + 0.0122Q); V is the traffic volume per cycle, obtained through the arrival information of connected vehicles; Q represents the queue length, which is the result of the straight - through vehicle traffic distribution in the following formula and is calculated as follows: L que,m = n s1,m + n sr1,m -(n s2,m + n sr2,m ); where L que,m is the number of queuing vehicles, then the queuing length Q = L que,m × vehicle length. In addition, when Q represents the queuing length of the straight-right lane, it is set to 0 to maximize the safety weight of the straight lane, that is, Q2 = 0; n s1,m , n s2,m respectively represent the number of straight vehicles from the straight lane during the red light of the m-th cycle, and the number of vehicles allocated to the straight lane and the straight-right lane after algorithm calculation; n sr1,m , n sr2,m respectively represent the number of straight vehicles from the straight-right lane, and the number of vehicles allocated to the straight lane and the straight-right lane after algorithm calculation; Indicates the average waiting time of queuing vehicles on Lane 1, which consists of two parts: the average queuing waiting time t AQWT and the start-to-departure time The average queuing waiting time refers to the time when the vehicle waits stationary for the red light during the red light period; the start-to-departure time represents the time difference from when the vehicle starts to move until it leaves the intersection. The calculation formula is as follows: where h is the saturated headway, and n l is the number of vehicles queuing on Lane 1, which is the result of traffic assignment, i.e.: n1 = n s1,m + n sr1,m = 6 + 3 = 9, n2 = n s2,m + n sr2,m = 0; In addition, when straight - through vehicles can queue on the straight - right lane, it will affect the subsequent arriving right - turn vehicles. Therefore, when l = 2, this influence needs to be considered, that is: where r r represents the proportion of right-turning vehicles in the straight right lane, which is 0.6; thus, it can be obtained that: Step 3.2: With the goal of minimizing the cost of traffic distribution, use the ant colony algorithm to optimize the straight - through vehicle traffic distribution result within one cycle, and obtain the queue length of the straight - through lane calculated according to the traffic distribution; Step 3.3: Based on the vehicle queuing situation in the straight - through lane, use this as the basis for adjusting the straight - right lane signal lights; Step 4: According to the queue length of the straight - through lane, adaptively indicate that the straight - right lane signal light is about to change by flashing; Step 5: Change the signal light of the straight - right lane to allow straight - through vehicles to change lanes into the straight - right lane.

2. The design and application method of the straight-right lane adaptive signal control in a connected environment according to claim 1, characterized in that In Step 1, the straight - right lane markings are located within the straight - right lane. The right - turn lane markings are normal markings, and the arrow position of the straight - through lane markings is regarded as a broken - solid line, indicating that straight - through vehicles can only pass on the straight - right lane under certain conditions.

3. The adaptive signal control design and its application method for the straight-right lane under the connected environment according to claim 2, characterized in that, The said certain conditions include: when the signal light turns red, if the dynamic queue length on the straight - through lane is not full, the straight - right lane only allows right - turn vehicles to pass; when the dynamic queue length is full, straight - through vehicles can queue or pass on the straight - right lane.

4. The design and application method of the straight-right lane adaptive signal control in the networked environment according to claim 1, characterized in that In Step 2, the collection of vehicle arrival information includes: in the connected environment, the vehicle conveys the arrival information of the vehicle to the signal control center at the intersection through vehicle - road communication, including the proportion of upcoming straight - through vehicles and right - turn vehicles during the red light period.

5. The design and application method of the straight-right lane adaptive signal control in the networked environment according to claim 1, characterized in that, In Step 4, the adaptive straight - right lane signal light includes: the straight - right lane signal light can update the dynamic queue length according to the traffic state per cycle, provide the optimal traffic indication, and achieve adaptive control.

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