T-shaped signal-lamp-free intersection optimization system based on signal lamp cooperation

Abstract

The invention discloses a T-shaped signal-lamp-free intersection optimization system based on signal lamp collaboration. The T-shaped signal-lamp-free intersection optimization system is suitable for a traffic scene that a branch only allows right turning. Comprising a main road and branch road monitoring module, a gap generation module, a vehicle cooperative guiding module and a conflict area monitoring module, and provides a conflict avoidance channel for left-turn traffic flow of a main road by coordinating signal control of intersections with signal lamps on two sides of the main road, dynamically adjusting conflict time difference of opposite traffic flow and periodically generating traffic-flow-free safety gap windows. The method specifically comprises the steps of monitoring the states of main road two-way traffic flow and branch right-turn traffic flow in real time, intercepting opposite traffic flow through an upstream signal lamp, synchronously guiding left-turn traffic flow to pass in a safe window period, and triggering a response mechanism by illegal intruding vehicles, and meanwhile, dynamically optimizing an afflux instruction of branch right-turn traffic flow based on the density of the main road traffic flow, physical isolation of the left-turn traffic flow and the opposite-direction straight traffic flow is achieved, the conflict probability approaches zero, the average delay time of the left-turn traffic flow is shortened by 31% or above, the right-turn traffic flow convergence efficiency is improved, and the method has the advantages of being low in improvement cost and high in traffic safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of traffic signal control, in particular to a T-shaped signal-free intersection optimization system based on signal light coordination. BACKGROUND

[0002] The development of cities has complicated the traffic network, and the traditional traffic signal control mode is difficult to adapt to the increasingly complex traffic logic, especially in the scene of specific types of intersections (such as T-shaped signal-free intersections), the balance between traffic efficiency and safety is particularly prominent. At present, the traffic management of T-shaped intersections mainly relies on the following two ways:

[0003] Full signal light control: signal lights are set at the intersection of the main road and the branch road, and the vehicle flow is alternately passed through time division. However, for T-shaped intersections where the branch road only allows right turns, this control strategy has significant drawbacks. The conflict between right-turn vehicle flow and straight-through vehicle flow on the main road is small, but the forced waiting of signal lights increases vehicle idling emissions, making it difficult to fully utilize the passing gap time, which easily leads to low traffic efficiency.

[0004] Signal-free management: Some intersections use signal-free design and rely on drivers to judge passing priority. However, this mode is prone to conflict risks in high-flow scenarios, especially the intersection conflict between left-turn vehicle flow on the main road and opposite straight-through vehicle flow, which may cause serious traffic accidents.

[0005] Car-road coordination technology (such as V2X communication): mainly focuses on adaptive timing or green wave band design at single-point intersections, lacks a systematic safety gap generation mechanism for signal-free intersections, such as difficulty in avoiding conflicts of left-turn vehicle flow on the main road, low efficiency of right-turn vehicle flow on the branch road, and high cost. The defects have not been improved. Therefore, a new signal control system is needed to ensure cost control and traffic safety, and to further overcome the low-efficiency traffic situation of T-shaped signal-free intersections. SUMMARY

[0006] The present application discloses a T-shaped signal-free intersection optimization system based on signal light coordination, which acquires fusion data through millimeter wave radar and geomagnetic sensors, establishes intersection traffic logic with the help of gap generation module, vehicle flow coordination guidance module and conflict area monitoring module to avoid conflicts and improve congestion at signal-free intersections.

[0007] Technical solution:

[0008] A T-shaped signal-free intersection optimization system based on signal light coordination, the system comprises:

[0009] The main road bidirectional and branch road monitoring modules are deployed in the main road bidirectional lanes to collect real-time traffic flow speed, position and turning intentions, and send them to the gap generation module;

[0010] The gap generation module communicates with the signal control systems of intersections A and B on both sides of the main road to adjust the straight-through traffic flow a in intersection A. s and left-turning traffic a l With the straight-through traffic flow b at intersection B s and left-turning traffic b l The green light time difference periodically generates left-turn traffic flow c in intersection C, which is without traffic lights. l The safe gap window is sent to the traffic flow cooperative guidance module and the conflict zone detection module;

[0011] The traffic flow coordination and guidance module is used for traffic flow turning left onto the main road. l Send an acceleration command to the straight-through traffic flow c on the main road. s Send a traffic control command and direct right-turning traffic flow c to the branch road. r Provides dynamic guidance instructions for merging into the main road;

[0012] The conflict zone monitoring module is deployed in the left-turning traffic flow on the main road. l c with the main road straight traffic flow s In the conflict zone, real-time detection of straight-through traffic flow on the main road. s illegally entering the left-turn traffic flow l The safety gap window is set and the emergency response mechanism is triggered.

[0013] Furthermore, the main road bidirectional and branch road monitoring module collects traffic flow speed, position and turning intention in real time through multi-source data fusion of millimeter-wave radar array and geomagnetic sensor. The millimeter-wave radar array and geomagnetic sensor are set at intersection C.

[0014] Furthermore, the gap generation module generates the safety gap window as follows:

[0015] Phase connection control: At traffic light intersections A and B on both sides of the main road, a fixed connection relationship between the left-turn phase and the straight-ahead phase is set to ensure that the green light for the straight-ahead phase starts after the left-turn phase ends, forming a continuous traffic flow;

[0016] Calculate the safety gap window interval: based on the straight traffic flow a l and left-turning traffic a s Given the arrival and travel times of the traffic flow at intersection C, calculate the trigger and end times for the required safety gap. l Prior to a s Release, the safety gap window range is [T a T p ], where T a For left-turning traffic flow al The time point when the first vehicle reaches intersection C, T p For the straight flow a s The time point when the last vehicle passes through intersection C.

[0017] Further, T a And T p The specific calculation is as follows:

[0018]

[0019] Where T0is the left-turn flow a l The release time, S r The distance from intersection A to intersection C, v avg The average speed of the flow;

[0020]

[0021] Where t l The left-turn green light duration of intersection A, t s The straight green light duration of intersection A, S r The distance from intersection A to intersection C, L is the queue length of the left-turn flow cl of intersection C at the end of the straight green light of intersection A, v avg The average speed of the flow in normal driving, v lavg The average speed of the flow in left-turn driving.

[0022] Further, control the left-turn flow b l The first vehicle reaches intersection C after the end of the safety gap window, the left-turn flow b l The release time:

[0023]

[0024] Where S l The distance from intersection B to intersection C, v avg The average speed of the flow in normal driving.

[0025] Further, the flow coordination guiding module comprises:

[0026] The left-turn flow unit: sends an acceleration instruction to the vehicle terminal through V2X communication,

[0027] The opposite straight flow control unit: dynamically limits the upstream signal light, and induces the main road straight flow c s To decelerate to the target speed, prolong the time of its arrival at the conflict area, and stop and wait for the main road left-turn flow c l To drive safely;

[0028] The right-turn flow optimization unit: according to the main road straight flow c sSafety gap, turn right to branch flow c r Send "accelerate merge" or "slow down wait" instructions.

[0029] Further, the emergency response of the conflict area monitoring module includes:

[0030] When the intruding speed v alert When the intruding speed v is greater than 30 km / h, the following operations are synchronously performed: sending an emergency braking instruction to the conflict flow, i.e., the target flow deceleration is greater than or equal to 18 km / h.

[0031] Beneficial effects:

[0032] 1. The present application forms a safety gap by controlling the time at which the traffic flows on both sides of the main road arrive at the intersection without a traffic light, thereby avoiding road conflicts between left-turn and straight traffic flows at the intersection without a traffic light, and ultimately effectively improving the congestion phenomenon at the intersection without a traffic light.

[0033] 2. The present application combines the straight and left-turn traffic flows at intersections A and B with traffic lights to form a continuous traffic flow, so that road conflicts only need to be considered once in one traffic cycle, thereby reducing the difficulty of traffic light timing and improving the response speed of signal traffic.

[0034] 3. The present application realizes a safety gap generation mechanism for a T-shaped intersection without a traffic light, and only needs to collect data through multi-source data fusion of a millimeter wave radar array and a geomagnetic sensor, in combination with a V2X communication function, thereby further compressing costs compared to laying out a T-shaped road section with traffic lights or modifying the structure of the intersection, and being suitable for implementation in a large area and for multiple types of road sections. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a schematic diagram of the combined traffic flow of left-turn and straight traffic at intersections A and B according to an embodiment of the present application;

[0036] Figure 2 is a schematic diagram of the conflict area of a T-shaped intersection C according to an embodiment of the present application;

[0037] Figure 3 is a schematic diagram of the deployment and collection of devices on the main road and the branch road according to an embodiment of the present application;

[0038] Figure 4 is a schematic diagram of the overall road design according to an embodiment of the present application;

[0039] Figure 5 is a system workflow diagram according to an embodiment of the present application;

[0040] Figure 6 is an experimental schematic diagram according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] With reference to the drawings and embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0042] As shown in Figures 1-6 , the present application discloses a T-shaped signal-free intersection optimization system based on signal light coordination, which comprises a main road bidirectional and branch monitoring module deployed in the main road bidirectional lane for real-time collection of vehicle flow speed, position and turning intention, and sending to a gap generation module. In this embodiment, the branch of the T-shaped intersection is a one-way lane allowing only right turn.

[0043] The gap generation module is in communication connection with signal control systems of signal light intersections A and B on both sides of the main road, for adjusting the green light release time difference of straight flow a s and left turn flow a l in intersection A and straight flow b s and left turn flow b l in intersection B, periodically generating a safe gap window of left turn flow c l in signal-free intersection C, and sending to a vehicle flow coordination guiding module and a conflict area detection module. The vehicle flow merging and conflict of intersections A, B and C are as shown in Figures 1-2 .

[0044] The vehicle flow coordination guiding module is used for sending an acceleration through instruction to the main road left turn flow c l , sending a flow interception control instruction to the main road straight flow c s , and providing a dynamic guiding instruction for the branch right turn flow c r to merge into the main road.

[0045] The conflict area detection module is deployed in the conflict area of the main road left turn flow c l and the main road straight flow c s , for real-time detection of the main road straight flow c s violating the safe gap window of the left turn flow c l and triggering an emergency response mechanism.

[0046] The main road bidirectional and branch monitoring module collects vehicle flow speed, position and turning intention in real time through multi-source data fusion of millimeter wave radar array and geomagnetic sensor. The millimeter wave radar array and the geomagnetic sensor are arranged 100 meters away from each lane of intersection C. As shown in Figure 3 , in this embodiment, the millimeter wave radar array Geomagnetic sensors are installed at two locations: one in the left-turn lane of the section from intersection A to intersection C, 100 meters from intersection C; and another in the right-turn lane of the section from intersection B to intersection C, 100 meters from intersection C. These sensors are used to track traffic flow dynamics. The radar array, located at the same position as the right-turn exit of intersection C and the millimeter-wave radar array from intersection A to intersection C, is used to detect the queue length of right-turning vehicles. The overall road design in this embodiment is as follows: Figure 4 As shown.

[0047] The gap generation module generates a safety gap window as follows:

[0048] Phase connection control: At traffic light intersections A and B on both sides of the main road, a fixed connection relationship between the left-turn phase and the straight-ahead phase is set to ensure that the green light for the straight-ahead phase starts after the left-turn phase ends, forming a continuous traffic flow;

[0049] Calculate the safety gap window interval: based on the straight traffic flow a l and left-turning traffic a s Given the arrival and travel times of the traffic flow at intersection C, calculate the trigger and end times for the required safety gap. l Prior to a s Release, the safety gap window range is [T a T p ], where T a For left-turning traffic flow a l The time when the first vehicle arrives at intersection C, T p For straight-through traffic flow a s The last car passed through intersection C at time point.

[0050] T a and T p The specific calculations are as follows:

[0051]

[0052] Where T0 represents the left-turning traffic flow a l At the time of release, S r v is the distance from intersection A to intersection C. avg The average speed of the traffic flow;

[0053]

[0054] Where t l Let t be the duration of the left-turn green light at intersection A. s S is the duration of the green light for straight traffic at intersection A. r Let L be the distance from intersection A to intersection C, and let L be the queue length of left-turning traffic at intersection C when the green light for straight traffic ends at intersection A. avg v represents the average speed of normal traffic flow. lavgThe average speed of the vehicle flow for left turn.

[0055] The straight-through vehicle flow a at intersection A s The time required for the last vehicle to reach the tail of the current left-turn queue, where S r The straight-through vehicle flow a at intersection A s The distance of the last vehicle to reach the tail of the current left-turn queue. The left-turn vehicle flow c at intersection C when the straight-through green light at intersection A ends l The time required to pass through the intersection without a traffic light.

[0056] Control the left-turn vehicle flow b l The first vehicle reaches intersection C after the end of the safety gap window, left-turn vehicle flow b l Release time:

[0057]

[0058] Where S l The distance from intersection B to intersection C, v avg The average speed of the vehicle flow under normal conditions.

[0059] During the safety gap window, b1, b s Enter the conflict zone, and at the same time, release the left-turn vehicle flow c l Traffic restrictions.

[0060] The vehicle flow coordination guidance module includes:

[0061] Left-turn vehicle flow unit: send acceleration instructions to the vehicle terminal through V2X communication, and the target speed is calculated as: v target = min(v current × 1.2, v limit );

[0062] Opposite straight-through vehicle flow control unit: dynamically limit the upstream traffic light and induce the main road straight-through vehicle flow c s To slow down to the target speed, extend its arrival time at the conflict zone, and park and wait for the main road left-turn vehicle flow c l To safely exit;

[0063] Right-turn vehicle flow optimization unit: according to the safety gap of the main road straight-through vehicle flow c s Send "accelerate and merge" or "slow down and wait" instructions to the branch right-turn vehicle flow c r

[0064] The emergency response of the conflict zone monitoring module includes:

[0065] Detect the break-in speed v alert ​When the speed is greater than 30km / h, the following operations are performed synchronously: sending an emergency braking instruction to the conflicting traffic flow, i.e., the target traffic flow deceleration is greater than or equal to 18km / h.

[0066] In summary, as shown in the figure, the overall operation process of the system in the embodiment is as follows: Figure 5

[0067] The output end of the main road bidirectional monitoring module and the branch road monitoring module is connected with the input end of the gap generation module, and the output end of the gap generation module is connected with the traffic flow cooperative guidance module and the conflict area monitoring module respectively. When the straight traffic flow a s and the left-turn traffic flow a l start to be released in intersection A, the main road bidirectional monitoring module deployed therein sends the speed, position and left-turn number of the traffic flow from intersection A to intersection C to the safety gap generation module, calculates the time point T l when the first vehicle of the left-turn traffic flow a a arrives at intersection C, and the time point T s when the last vehicle of the straight traffic flow a p passes through intersection C, generates a safety gap window for the left-turn traffic flow c l , and then sends the safety gap to the traffic flow cooperative module to control the opposite traffic flow and trigger the emergency response mechanism of the conflict area monitoring module. During this period, the left-turn traffic flow b l in intersection B starts to be released at the calculated time point T b , the branch right-turn vehicle freely passes through intersection B before the left-turn traffic flow b l arrives at intersection C, the vehicle cooperative module controls b l to arrive at intersection C at the time point T p , the left-turn traffic flow c l empties the left-turn lane before the time point T p , and the branch right-turn traffic flow c r enters the gap.

[0068] As shown in the figure, the embodiment selects a signal-free T-shaped intersection on the Ninghuai Highway for simulation experiment, and the target optimization intersection peak flow and peak flow data are shown in Table 1:

[0069] Table 1

[0070]

[0071] Compared with the traditional Webster timing method, the left-turn delay optimization rate can reach more than 31% in the peak period and the peak period, and the specific comparison results are shown in Table 2:

[0072] Table 2

[0073]

[0074] ​The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent transformation or modification according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A T-shaped intersection without signal light optimization system based on signal light coordination, characterized in that, The system comprises: The main road two-way and branch monitoring module is arranged on the main road two-way lane and is used for collecting the vehicle flow speed, position and turning intention in real time and sending to the gap generation module; The gap generating module is in communication connection with the signal control systems of the signalized intersections A and B on both sides of the main road, and is used for adjusting the green light release time difference of the straight traffic flow a in intersection A s and the left-turn traffic flow a l in intersection B s and the left-turn traffic flow b l in intersection B l The gap generating module is in communication connection with the signal control systems of the signalized intersections A and B on both sides of the main road, and is used for adjusting the green light release time difference of the straight traffic flow a in intersection A s and the left-turn traffic flow a l in intersection B s and the left-turn traffic flow b l in intersection B l The gap generating module is in communication connection with the signal control systems of the signalized intersections A and B on both sides of the main road, and is used for adjusting the green light release time difference of the straight traffic flow a in intersection A s and the left-turn traffic flow a l in intersection B s and the left-turn traffic A traffic flow coordination module is used to guide the left-turn traffic flow c of the main road l An acceleration-through instruction is sent to the straight traffic flow c of the main road s A cut-off control instruction is sent to the right-turn traffic flow c of the branch road r Dynamic guidance instructions are provided for merging into the main road A conflict zone monitoring module is deployed at the left-turn traffic flow c l of the main road, to detect in real-time the through traffic flow c s of the main road that violates the safety gap window and triggers an emergency response mechanism when it illegally intrudes into the left-turn traffic flow c s of the main road. l ​ 2. The signal light coordination based T-junction signal free intersection optimization system as claimed in claim 1, wherein, The main road two-way and branch monitoring module collects the vehicle flow speed, position and turning intention in real time through the multi-source data fusion of the millimeter wave radar array and the geomagnetic sensor, and the millimeter wave radar array and the geomagnetic sensor are arranged at the intersection C.

3. The signal light coordination based T-junction signal free intersection optimization system as claimed in claim 2, wherein, The gap generation module generates the safety gap window as follows: Phase connection control: the fixed connection relationship of the left-turn phase and the straight-going phase is set at the signal light intersections A and B on the two sides of the main road, the straight-going phase green light is ensured to start after the left-turn phase ends, and continuous vehicle flow is formed; Calculate the safe gap window interval: According to the time of the straight flow a l and the left-turn flow a s arriving at the intersection C and the passing time, calculate the trigger time point and the end time point of the required safe gap, a l Release before a s The safe gap window interval is [T a , T p ], where T a is the time point at which the first vehicle of the left-turn flow a l arrives at the intersection C, and T p is the time point at which the last vehicle of the straight flow a s passes through the intersection C.

4. The signal light coordination based T-junction signal free intersection optimization system of claim 3, wherein, T a and T p The specific calculation is as follows: where T0is the left-turn traffic flow a l the release time, S r is the distance from intersection A to intersection C, v avg is the average speed of the traffic flow; where t l is the left-turn green time of intersection A, t s is the straight green time of intersection A, L is the distance from intersection A to intersection C, L l is the queue length of left-turn traffic flow of intersection C at the end of straight green time of intersection A, v avg is the average speed of traffic flow under normal conditions, and v lavg is the average speed of left-turn traffic flow.

5. The signal light coordination based T-junction signal free intersection optimization system as claimed in claim 4, wherein, Control left-turn flow b l First vehicle arrives at intersection C after safety gap window ends, left-turn flow b l Release time: where S l is the distance from intersection B to intersection C, v avg is the average speed of the traffic flow under normal conditions.

6. The traffic light coordination based T-type traffic light intersection optimization system of claim 1, wherein, The vehicle flow cooperative guidance module comprises: The left-turn vehicle flow unit sends the acceleration instruction to the vehicle-mounted terminal through the V2X communication, Opposite straight flow control unit: through upstream signal light dynamic limit, and induce the main road straight flow c s Slow down to target speed, extend its time to reach the conflict area, and stop waiting for the main road left turn flow c l Safe out; Right-turn traffic optimization unit: according to the main road straight traffic flow c s Safety gap, to the branch right-turn traffic flow c r Send "speed up merge" or "slow down wait" instructions.

7. The traffic light coordination based T-type traffic light intersection optimization system of claim 1, wherein, The emergency response of the conflict area monitoring module comprises: The intruder speed v is detected alert When the speed is > 30 km / h, the following operations are performed synchronously: sending an emergency braking instruction to the conflicting traffic flow, i.e. target traffic flow deceleration > 18 km / h.

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