CN103186984B - Method for triggering transformation of steering function of variable guidance lanes at urban intersections - Google Patents

Abstract

The invention discloses a method for triggering the change of steering function of a variable guiding lane at an urban intersection, which includes: the arrangement of two rows of coil detectors; and the triggering method and process for changing the steering function of a variable guiding lane. The present invention starts from the most intuitive performance of unbalanced steering traffic applicable to variable guide lanes, that is, there is an obvious difference in the queue length of each steering, and judges the queue status of each steering through the occupancy of the two rows of detectors. The steering saturation is further judged, and the process of specifically determining the conversion of the steering function of the variable steering lane is given to improve the utilization rate of the variable steering lane, shorten the queue length of the entrance road, and reduce the delay of vehicles at the intersection.

Description

A triggering method for steering function transformation of variable guiding lanes at urban intersections

technical field

The invention belongs to the field of road traffic control, and in particular relates to a trigger method for steering function conversion of a variable guiding lane.

Background technique

When traditional signal-controlled intersections are set up, the lane functions are usually kept unchanged, and signal adjustments are used to respond to changes in traffic demand. This method can adapt to the situation where the traffic volume of each turn at the entrance has small fluctuations, but for those entrances with obvious fluctuations in the traffic volume of each turn at different times, it will often cause the opposite traffic flow in the same phase to increase due to the increase in the passing time of the green light. Waste of resources, or cause a single steering traffic queue to be too long and cause congestion. At this stage, the transformation of the steering function of the variable steering lane often requires the traffic police to observe and control the traffic volume at the intersection in real time. This subjective judgment often results in inappropriate transformation time, traffic jams or violations, and there are also problems such as low utilization rate. .

Previous studies have proposed methods such as induction control, double stop line control, main and pre-signal control, but the proposed process is not very operable in actual implementation, and the acquisition and collection of parameters are difficult.

Contents of the invention

The purpose of the present invention is to propose a method for triggering the change of steering function of a variable directional lane at an urban intersection, which overcomes the drawbacks of relying on manual determination of the changing timing of the variable directional lane, improves the utilization efficiency of the variable directional lane, and shortens the length of the traffic queue at the entrance. Reduce vehicle delays at intersections.

The technical solution adopted in the present invention is: the variable-guiding lane steering function change trigger method of the urban intersection of the present invention, which utilizes detectors to monitor in real time the passing flow of each turn and the range where the maximum queuing of each turn is located, reasonably selects the timing of the turn function change, and improves Lane utilization, reducing vehicle intersection delays, involves the following steps:

1) Arrangement of two rows of detectors

① The detection group J1 is arranged at the end of the widening section at L1 upstream of the entrance road. The number is the sum of the coil detectors on the entrance straight lane, left-turn lane, and variable steering lane. It is used to detect the number of passing vehicles in each lane, and the number of detectors Occupancy time and other data, so as to obtain traffic parameters such as each turning flow of the entrance road, coil occupancy, etc. ② The detection group J2 is arranged in the upstream section of the entrance road regardless of the traffic flow turning. The length of the gradual change section from the entrance road is L2, and the number is the sum of the detectors on each lane of the road section. It is used to detect and judge whether the traffic queue of each upstream lane is too long.

2) The detection method of the detector being occupied

When the queue spreads to where the detector is located, the response at the detector is an excessively long level. Therefore, when the detector has no continuous level during the red light period (the length of the level exceeds a certain limit), it means that the detector is not occupied, that is, the queue is not propagated to the inductive detector. Set a level continuous limit, and monitor the level length in real time. If the level length exceeds the limit, it means that the detector is occupied and the queue has reached the position of the detector.

3) The process of judging the change of the steering function of the variable steering lane is as follows:

3.1) Judgment of the maximum queue length of each direction

Note that the stop line to the detection group J1 is the interval M1, the detection group J1 to the detection group J2 is the interval M2, and the detection group J2 to the subsequent road section is M3. According to the section where the largest queue tail is located in each steering cycle, there are three queuing situations: ① The queue tail of one steering is in the interval M1, while the tail of the other steering queue is in the interval M3, marked as ○, indicating the steering function of the variable steering lane There should be a change; ②The tails of the two steering queues are in the same section, denoted as ╳, which means that the steering function of the variable steering lane remains unchanged; ③The tails of the two steering queues are respectively in the interval M1 and interval M2 or in the interval M2 And the interval M3, denoted as △, indicates that it needs to be further discussed through the saturation of traffic flow in each turn.

3.2) Further determination of saturation

The result of the maximum queuing length difference is △. It is necessary to further judge the difference in the saturation of each turn, and the following conditions should be met: ①The traffic flow saturation x _A of the turn with a small queuing length should be less than a certain threshold x _l ; ②The turn with a longer queuing length The traffic saturation x _B should be greater than a certain threshold x _h ; ③ The difference Δx of saturation in two directions should be greater than a certain threshold x _m . When the above conditions are met, the steering function of the variable steering lane is changed.

The calculation method of the saturation of each turning lane and the determination method of the threshold in the saturation judgment process are as follows:

a. Calculation of Saturation

Taking the average value of the traffic data collected in three consecutive periods as the calculation value, let L _i be the left-turn traffic flow data obtained in the i-th cycle, and T _i be the through-going traffic flow data obtained in the i-th cycle. Then the average value of left-turn traffic flow in the last three periods is recorded as L _i '=(L _i +L _i-1 +L _i-2 )/3, and the average value of straight-going traffic flow is recorded as T _i '=(T _i +T _{i- 1} +T _i-2 )/3. by formula Calculate each steering saturation, where: j—the number of the turning traffic flow, generally j=1 means turning left, and j=2 means going straight; q _j —the single-lane traffic flow of j turning traffic flow, pcu/h; x _j —j turning traffic flow Saturation; CAP _j — j-turning capacity of traffic flow, pcu/h.

b. Determination of Saturation Judgment Threshold

(n _j —the number of entrance lanes for j-turning traffic flow; α—correction coefficient, which can be 0.8~0.9); ②x _B >x _h ＝0.9; (n _A —the number of entrance lanes for traffic flow in the direction with smaller queue length; β—correction coefficient, which can be 0.8~0.9).

Beneficial effects: 1. The triggering method of the steering function conversion of the variable steering lane proposed by the present invention uses two rows of detectors to detect the difference in queuing length of each steering, combined with the further determination of saturation, to ensure the steering function of the variable steering lane. The change will not have a severe impact on traffic flow in the direction in which the number of lanes is reduced.

2. The method for triggering the function change of the variable-guiding lane proposed by the present invention is simple and easy to implement, relying on two rows of detectors to judge the queue length, the judgment method is more reliable, effectively improves the utilization rate of the variable-guiding lane, shortens the difference in queuing, and reduces the entrance All trains are delayed.

Description of drawings

Figure 1 is a schematic diagram of the lane distribution, numbering and detector layout of the entrance road.

Fig. 2 is a flow chart for judging the steering function transformation of the variable steering lane at the intersection, taking Fig. 1 as an example.

Fig. 3 is a flow chart of judging triggering of function change of variable guide lane.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Step 1: Arrange two rows of detectors at the entrance as shown in Figure 1;

Step 2: Taking Figures 2 and 3 as examples, discuss according to the current steering function of the variable steerable lane, and take one signal period as the detection period. When the green light of the directional control signal of the target entrance road just ends, and all turns are red lights, it is taken as the starting time of the cycle detection.

(1) The initial state of the variable guiding lane is the left-turn lane

1) Detector 2 is not occupied

It shows that the queuing of vehicles on the variable steering lane has not spread to the detector 2 at this time, and the detector 1 is also unoccupied or low-occupancy under normal circumstances. At this time, the left-turning traffic flow is in the initial queuing stage.

① If detectors 3 and 6 are both occupied and the queue of straight traffic is too long, change the steering function of the variable steering lane to go straight.

② If detector 3 is occupied but detectors 5 and 6 are not occupied, the straight line is in the stage of queuing spread. At this time, the steering saturation needs to be judged, and the left-turning and straight-going traffic flows are respectively obtained through the detectors 1, 2 and 3, and the saturations of each steering are calculated. When the saturation judgment condition (x _A < x _l , x _B > x _h , Δx≥x _m ) is satisfied, the steering function of the variable steering lane will be changed to go straight.

2) Detector 2 is occupied and Detector 4 is not occupied

It shows that the queue of left-turn traffic has already overflowed the widening section and reached the transition section.

①If detectors 3 and 6 are both occupied at this time, it means that the straight traffic flow is queuing up. At this time, the traffic volume obtained by detectors 1, 2 and detector 3 is used to calculate the saturation difference of each turn. When the saturation judging condition (x _A < x _l , x _B > x _h , Δx ≥ x _m ) is met, and the occupancy of detector 6 increases or the occupancy of detector 1 decreases, the steering function of the variable steering lane becomes for going straight.

②If the detector 6 is not occupied, there is no need to adjust the function of the variable guiding lane at this time.

3) Both detectors 2 and 4 are occupied

At this time, the queue of left-turning traffic has already traced back to the road section, and the unreasonable setting of variable guiding lanes is not considered. If the detectors 3 and 6 are both in the occupied state, it means that the flow in all directions of the entrance road is too large and exceeds the capacity of the entrance road. The change of the lane function can not bring about effective improvement, and other control methods should be considered.

(2) The initial state of the variable guiding lane is the straight lane

1) Detector 2 is not occupied

It shows that the queuing of vehicles on the variable steering lane has not spread to the detector 2 at this time, and the detector 3 is also unoccupied or has a low occupancy rate under normal circumstances. At this time, the through traffic flow is in the initial queuing stage.

① If detectors 1 and 4 are both occupied, that is, the queue of left-turn traffic is too long, change the steering function of the variable steering lane to turn left.

② If detector 1 is occupied but detector 4 is not occupied, the left turn is in the stage of queuing spread. At this time, it is necessary to judge the steering saturation, obtain the left-turn traffic flow and straight-going traffic flow through detector 1, detector 2, and 3 respectively, and calculate the saturation of each steering. When the saturation judging conditions (x _A < x _l ′, x _B > x _h ′, Δx ≥ x _m ′) are met, the steering function of the variable steering lane is changed to turn left.

2) Detector 2 is occupied and Detector 6 is not occupied

It shows that the queuing of straight traffic flow has overflowed the widening section and reached the transition section.

①If detectors 1 and 4 are both occupied at this time, it means that the left-turning traffic flow is queuing up. At this time, the traffic volume obtained by detector 1 and detector 2 and 3 is used to calculate the saturation difference of each turn. When the saturation judging condition (x _A < x _l ′, x _B > x _h ′, Δx ≥ x _m ′) is met, and the occupancy of detector 4 increases or detector 3 decreases, the variable steering lane steering function will be to turn left.

②If the detector 4 is not occupied, there is no need to adjust the function of the variable guiding lane at this time.

3) Both detectors 2 and 6 are occupied

At this time, the queue of straight traffic flow has been traced back to the road section. If detectors 1 and 4 are both occupied, it means that the flow in all directions of the entrance road is too large and exceeds the capacity of the entrance road, and the change of lane function can no longer bring about effective improvement. Other means of control should be considered.

Due to the high dispersion of vehicle arrivals at the entrance lanes in urban roads, the fluctuation of traffic flow in adjacent cycles is large, and the basis for lane function change cannot be based on whether a single cycle meets the trigger conditions. Generally, three consecutive periods of observation are observed, and if the conditions are met within the continuous period, the steering function of the variable steering lane is changed.

It should be pointed out that those skilled in the art can make some improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention. All components that are not specified in this embodiment can be realized by existing technologies.

Claims (2)

1. A variable guiding lane steering function conversion triggering method at an urban intersection, characterized in that: comprising the following steps: 1) Arrangement of two rows of detectors Set up two sets of detectors on the entrance road with variable guiding lanes: ① The detection group J1 is arranged at the end of the widening section at L1 upstream of the entrance road, and the number is the coil detectors on the entrance straight lane, left-turn lane, and variable guiding lane The sum of is used to detect the number of passing vehicles in each lane and the time data occupied by the detectors, so as to obtain the traffic parameters of each turning flow of the entrance road and the traffic parameters occupied by the detectors; The length of the gradual transition section of the entrance road is L2, and the number is the sum of the detectors on each lane of the road section, which is used to detect and judge whether the traffic queue of each lane in the upstream is too long; 2) The detection method of the detector being occupied When the queue spreads to the position where the detector is located, the reaction at the detector is too long level; therefore, when the detector has no continuous level during the red light, it means that the detector is not occupied, that is, the queue is not propagated to the coil detector ;Set a level continuous limit value, monitor the level length in real time, if the level length exceeds the limit value, it means that the detector is occupied and the queue has reached the position of the coil; 3) The process of judging the transformation of the steering function of the variable steering lane is as follows: 3.1) Determination of the maximum queue length of each direction Note that the stop line to the detection group J1 is the interval M1, the detection group J1 to the detection group J2 is the interval M2, and the detection group J2 to the subsequent road section is M3; according to the interval where the largest queuing queue tail is located in each turning cycle, there are three queuing situations: ① a certain The tail of one steering queue is in the interval M1, while the tail of the other steering queue is in the interval M3, and the result of the maximum queue length difference is recorded as ○, indicating that the steering function of the variable steering lane should be changed; ②The tails of the two steering queues are in the same interval , the result of the maximum queue length difference is recorded as ╳, which means that the steering function of the variable steering lane remains unchanged; ③The tails of the two steering queues are respectively in the interval M1 and interval M2 or in the interval M2 and interval M3 respectively, the result of the maximum queue length difference Denoted as △, it needs to be further discussed through the traffic saturation of each turn; 3.2) Further determination of saturation The result of the maximum queuing length difference is △. It is necessary to further judge the difference in the saturation of each turn, and the following conditions should be met: ①The traffic flow saturation x _A of the turn with a small queuing length should be less than a certain threshold x _l ; ②The turn with a longer queuing length The traffic saturation x _B should be greater than a certain threshold x _h ; ③ The difference Δ _x of saturation in two directions should be greater than a certain threshold x _m ; when the above conditions are met, the steering function of the variable steering lane will be changed. 2. The variable guiding lane steering function change triggering method at an urban intersection according to claim 1, characterized in that: the calculation method of the saturation of each turning lane and the determination method of the threshold in the saturation judgment process: 2.1) Calculation of saturation Taking the average value of the traffic data collected in three consecutive periods as the calculation value, let L _i be the left-turn traffic flow data obtained in the i-th period, and T _i be the through-going traffic flow data obtained in the i-th period; The average value of traffic flow is recorded as L _i '=(L _i +L _i-1 +L _i-2 )/3, and the average value of straight traffic flow is recorded as T _i '=(T _i +T _i-1 +T _i-2 ) /3; by formula Calculate each turning saturation, where: j—the number of the turning traffic flow, generally j=1 means turning left, and j=2 means going straight; q _j —the single-lane traffic flow of j turning traffic flow, pcu/h; x _j —j turning traffic flow Saturation; CAP _j — j-turning capacity of traffic flow, pcu/h; 2.2) Determination of saturation judgment threshold ① Among them: n _j - the number of entrance lanes of j-turning traffic flow; α - correction coefficient, take 0.8~0.9; ② x _B > x _h = 0.9; ③ Among them: n _A —the number of entrance lanes for traffic flow in the direction with smaller queuing length; β—correction coefficient, take 0.8～0.9.