CN105788301A - Special lane left-turn intersection pre-stop line and pre-signal setting method - Google Patents

Abstract

The invention relates to a method for setting a pre-stop line and a pre-signal at an intersection that uses a left turn to turn left, and integrates and optimizes its unique pre-stop line and pre-signal setting to ensure traffic On the basis of safety, the traffic capacity can be improved; the optimization setting method takes the maximum traffic capacity as the optimization goal, considers the constraints such as queue length, vehicle emptying and optimization parameter value range, and establishes a linear programming model for optimization. This method can integrate the key parameters of the special pre-stop line and pre-signal setting in a unified optimization model for synchronous optimization, so as to give full play to the traffic efficiency of the left-turn intersection and alleviate traffic congestion. .

Description

Pre-stop line and pre-signal setting method at crossings turning left by way

technical field

The invention relates to a method for setting a stop line and a signal timing at a traffic signal control intersection, more specifically, a method for setting a pre-stop line and a pre-signal at a left-turn intersection.

Background technique

At-grade intersections are the bottleneck nodes of urban road traffic. In order to improve the utilization efficiency of space-time resources at intersections, an unconventional intersection using "turning left" was proposed. However, the current design method mainly follows the design method of general level intersections. For the special pre-stop line and pre-signal at the left-turn intersection, the value is mainly based on experience. There is no targeted optimization setting method, and there is no Invention patents for such methods were retrieved.

According to the literature search of the prior art, it is found that there are mainly the following methods for the optimal design of signal control level intersections:

1. Conventional signal-controlled intersection geometric design. Specifically, it includes the position design of the parking line at the intersection, the function division of the lane, and the length design of the widening section of the intersection. China's "Urban Road Intersection Planning Specification GB50647-2011", "Urban Road Engineering Design Specification CJJ37-2012", and "Urban Road Intersection Design Specification CJJ152-2010" have relevant regulations on it.

2. Conventional signal control intersection signal control. Specifically, it includes signal phase sequence, cycle duration, green light time distribution of each flow direction, etc. His representative works in China include Urban Traffic Control and Traffic Management and Control.

3. Take the road and turn left at the intersection design. Borrowing left-turn intersections is an unconventional intersection design method, which sets part of the exit lane as a comprehensive functional area, and uses pre-signal control to use the comprehensive functional area as an exit lane or an entrance at different stages of the signal cycle The use of left-turn lanes provides additional right-of-way for left-turn traffic, thereby increasing the capacity of intersections. This design method was introduced in the invention patent application "Traffic indication system and control method for turning left at an intersection" (application number 201510675428.0); Organization and Signal Timing Method" (Application No. 201410276115.3) introduces its traffic organization and signal timing; and according to news from Sina.com, it has been practically applied in Handan, Hebei by way of a left-turn intersection (http://news .sina.com.cn/c/p/2014-05-16/165130151057.shtml).

Both method 1 and method 2 are designed for conventional signal-controlled intersections, and relatively mature technical achievements have been made so far.

Method 3 proposes the intersection type of turning left by the road, and the traffic capacity of the intersection can be improved through the dynamic use of the exit lane. Setting the pre-stop line upstream of the intersection and pre-signaling it is the key design content of this type of intersection, which is different from conventional signalized intersections. But at present, the design method of the conventional signal control intersection is mainly followed, and the pre-stop line position and pre-signal timing design are carried out sequentially. Among them, the pre-stop line generally adopts the value of the length of the widening section of the entrance road at the level intersection in the "Urban Road Intersection Planning Specification GB50647-2011" in Method 1, and 30-60m is recommended based on experience in the invention patent application 201410276115.3; the pre-signal control is generally Using the same timing method as the main signal at the intersection in method 2, the invention patent applications 201410276115.3 and 201510675428.0 mainly put forward corresponding requirements in terms of signal phase.

Conventional design methods do not consider the relationship between the position of the pre-stop line, the timing of the pre-signal, and the timing of the main signal at the intersection. From the point of view, the distance between the pre-stop line and the intersection stop line should be as large as possible, which can accommodate more vehicles and improve operating efficiency; but from the perspective of vehicle clearance constraints, the smaller the distance between the pre-stop line and the intersection stop line, the better , can reduce vehicle emptying time and improve operating efficiency. Therefore, the prior art lacks a more scientific and reasonable setting method for the unique pre-stop line and pre-signal control at the left-turn intersection.

Contents of the invention

For the deficiencies in the prior art, the purpose of the present invention is to provide a kind of pre-stop line and pre-signal setting method at the left-turn intersection, which is aimed at the pre-stop line and pre-signal setting method at the left-turn intersection. For the above contradictions, the key parameters of the pre-stop line position and pre-signal timing are integrated into a unified optimization model for simultaneous optimization, so as to improve traffic capacity on the basis of ensuring traffic safety.

Technical scheme of the present invention is as follows:

A method for setting a pre-stop line and a pre-signal at a left-turn intersection. By solving the following optimization model, the position of the pre-stop line and the timing of the pre-signal are simultaneously optimized. The optimization model is expressed by a linear programming model, with the maximum capacity as the optimization goal, and considering the queue length, vehicle emptying and the constraints of the range of optimization parameters, where:

The input parameters of the optimization model include: sp , the saturated flow rate of entering the left-turn lane at the pre-stop line, _veh /h; s _I , the saturated flow rate of the left-turn lane at the intersection stop line, veh/h; n, the number of left-turning lanes, C _I , the cycle duration of the main signal, s; g _I , the starting time of the green light of the main signal turning left, s; λ _I , the green signal ratio of the main signal turning left; r _I ', the starting time of the main signal of the entrance on the right side of the studied entrance turning left at the red light, s; v, the average vehicle speed, m/s; _{v min} , the minimum vehicle speed, m/s; s; d, average headroom distance of queuing vehicles, m; δ, safety time interval, s;

The output parameters of the optimization model include: L, the distance between the pre-stop line and the intersection stop line, m; C _p , the duration of the pre-signal cycle, s; g _p , the start time of the pre-signal green light, s; λ _p , the pre-signal green light letter ratio;

The optimization objective function is to maximize the traffic capacity of the left-turn lane, as shown in formula (1);

maxs _p λ _p (1)

The constraint of the queuing length requires that the length of the left-turning lane should be greater than or equal to the queuing length of the left-turning vehicle entering the lane, which satisfies the requirements of formula (2);

$\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; d</span>}}{\mathrm{<span\; class="notranslate">\; 3600</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

The constraints on the emptying of the vehicle are required to meet the following four constraints:

First, the start time of the pre-signal green light should satisfy that all vehicles using the exit have passed the section where the pre-stop line is located, that is, satisfy the requirements of formula (3);

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Second, the traffic capacity of the left-turning lane at the intersection stop line should be greater than or equal to the traffic capacity of the left-turning lane to ensure that the left-turning vehicles entering the lane can pass through the intersection in the same phase without vehicle stranded , which satisfies the requirement of formula (4);

s _I λ _I ≥ s _p λ _p (4)

Third, the time interval between the end time of the pre-signal green light and the end time of the corresponding left-turn green light of the main signal should be greater than or equal to the driving time of left-turning vehicles passing through the left-turn lane, so as to ensure that the vehicles entering the left-turn lane at the end of the pre-signal green light Vehicles can also pass through the intersection in this phase, which satisfies the requirements of formula (5);

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Fourth, the period length of the main pre-signal at the intersection should be consistent to ensure that the main pre-signal has a good coordinated control effect, that is, to meet the requirements of formula (6);

C _I =C _p (6)

The value range of the optimization parameters should meet the following four constraints:

One is that the optimization parameters are all non-negative, that is, the requirements of formula (7) are met;

L,g _p ,λ _p ,C _p ≥0(7)

The second is that the start time of the pre-signal green light should not be greater than the cycle duration, which meets the requirements of formula (8);

g _p ≤ C _p (8)

Third, the pre-signal green-to-signal ratio must not be greater than 1, which satisfies the requirements of formula (9);

λ _p ≤ 1(9)

Fourth, the end time of the pre-signal effective green light is the moment when the queue of the left-turn lane at the entrance dissipates and reaches the pre-stop line, which satisfies the requirements of formula (10).

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

The above optimization process needs to be considered: (1) From the perspective of queuing length constraints, the position of the pre-stop line should be set as far as possible from the intersection stop line, which can accommodate more queuing vehicles; (2) From the perspective of vehicle emptying constraints , the position of the pre-stop line should be set as close as possible to the stop line at the intersection, which can reduce the vehicle clearing time; this optimization setting method considers the contradiction between these two aspects, and establishes it in a unified optimization model, so as to ensure traffic safety On the basis of this, the traffic efficiency of the intersection design mode of turning left at the intersection can be brought into full play.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. The present invention provides a method for setting a pre-stop line and a pre-signal for a left-turn intersection.

2. The method of the present invention does not need to change the main signal timing of the intersection, and can realize the optimal setting of the pre-stop line and pre-signal at the left-turn intersection under the given main signal timing condition.

3. The method of the present invention considers the contradiction between the queue length constraint and the vehicle clearance constraint, and can maximize the traffic capacity of the left-turn lane on the basis of ensuring traffic safety.

Description of drawings

Fig. 1 is a schematic diagram of main parameters in the present invention;

Fig. 2 is a schematic diagram of vehicle emptying constraints in the present invention;

Fig. 3 is a schematic diagram of geometric conditions of intersections in Embodiment 1 of the present invention.

detailed description

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

A method for setting a pre-stop line and a pre-signal at a left-turn intersection. By solving the following optimization model, the position of the pre-stop line and the timing of the pre-signal are simultaneously optimized; the optimization model is expressed by a linear programming model, and the maximum capacity is used as the optimization Objective, and consider queue length, vehicle emptying and optimization parameter value range constraints. The main parameters of the model are shown in Figure 1, in which: 1 is the main signal, 2 is the pre-signal, 3 is the entrance under study, A is the pre-stop line, 4 is the left-turn lane by way, 5 is the left-turn lane of the entrance, 6 is the right inlet of the studied inlet.

The input parameters of the optimization model include: sp , the saturated flow rate of the left-turning lane at the pre-stop line, _veh /h; s _I , the saturated flow rate of the left-turning lane at the intersection stop line, veh/h h; n, the number of left-turning lanes, C _I , the period length of the main signal, s; g _I , the starting time of the main signal turning left and green light, s; λ _I , the green signal ratio of the main signal turning left; r _I ' , the start time of the main signal of the entrance on the right side of the researched entrance turning left at the red light, s; v, the average vehicle speed, m/s; v _min , the minimum vehicle speed, m/s; v _w , the speed of the queuing dissipated wave, m/s; d, the average headroom distance of queuing vehicles, m; δ, the safety time interval, s;

The output parameters of the optimization model include: L, the distance between the pre-stop line and the intersection stop line, m; C _p , the duration of the pre-signal period, s; g _p , the start time of the pre-signal green light, s; λ _p , the ratio of pre-signal green to signal ;

The objective function is to maximize the traffic capacity of the left-turn lane, as shown in formula (1);

maxs _p λ _p (1)

The constraint on the queue length requires that the length of the left-turning lane should be greater than or equal to the queue length of the left-turning vehicles entering the lane, which satisfies the requirements of formula (2);

$\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; d</span>}}{\mathrm{<span\; class="notranslate">\; 3600</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

The constraint of vehicle emptying requires to meet the following four constraints (as shown in Figure 2, where: A is the pre-stop line, B is the cross-stop line, D is the main signal left-turn green light phase of the right entrance of the entrance studied, R is the main signal turn left green light phase, F is the pre-signal green light phase):

First, the start time of the pre-signal green light should satisfy that all vehicles using the exit have passed the section where the pre-stop line is located, that is, satisfy the requirements of formula (3);

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Second, the traffic capacity of the left-turning lane at the intersection stop line should be greater than or equal to the traffic capacity of the left-turning lane to ensure that the left-turning vehicles entering the lane can pass through the intersection in the same phase without vehicle stranded , which satisfies the requirement of formula (4);

s _I λ _I ≥ s _p λ _p (4)

Third, the time interval between the end time of the pre-signal green light and the end time of the corresponding left-turn green light of the main signal should be greater than or equal to the driving time of left-turning vehicles passing through the left-turn lane, so as to ensure that the vehicles entering the left-turn lane at the end of the pre-signal green light Vehicles can also pass through the intersection in this phase, which satisfies the requirements of formula (5);

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Fourth, the period length of the main pre-signal at the intersection should be consistent to ensure that the main pre-signal has a good coordinated control effect, that is, to meet the requirements of formula (6);

C _I =C _p (6)

The value range of optimization parameters should meet the following four constraints:

One is that the optimization parameters are all non-negative, that is, the requirements of formula (7) are met;

L,g _p ,λ _p ,C _p ≥0(7)

The second is that the start time of the pre-signal green light should not be greater than the cycle duration, which meets the requirements of formula (8);

g _p ≤ C _p (8)

Third, the pre-signal green-to-signal ratio must not be greater than 1, which satisfies the requirements of formula (9);

λ _p ≤ 1(9)

Fourth, the end time of the pre-signal effective green light is the moment when the queue of the left-turn lane at the entrance dissipates and reaches the pre-stop line, which satisfies the requirements of formula (10).

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

The above optimization process needs to be considered: (1) From the perspective of queuing length constraints, the position of the pre-stop line should be set as far as possible from the intersection stop line, which can accommodate more queuing vehicles; (2) From the perspective of vehicle emptying constraints , the position of the pre-stop line should be set as close as possible to the stop line at the intersection, which can reduce the vehicle clearing time; this optimization setting method considers the contradiction between these two aspects, and establishes it in a unified optimization model, so as to ensure traffic safety On the basis of this, the traffic efficiency of the intersection design mode of turning left at the intersection can be brought into full play.

Specific examples:

The geometric conditions of the intersection in the embodiment of the present invention are shown in Figure 3, wherein: E is the east entrance, S is the south entrance, N is the north entrance, and W is the west entrance. The timing of the main signal at the intersection is shown in Table 1. Now the west entrance plans to set up a left-turning lane by way, adopt the method in the present invention, according to the maximum traffic capacity after setting up the left-turn lane by way, optimize the position of the pre-stop line and the timing of the pre-signal, and compare with the traditional Intersection design for comparison. The design input parameters are: the saturated flow rate at the pre-stop line entering the bypass left-turn lane, sp , which is _1600veh /h; the saturated flow rate of the bypass left-turn lane at the intersection stop line, s _I , which is 1800veh/h h; duration of the main signal cycle, C _I is 120s; the starting time of the main signal turning left to green light, g _I , is 60s; the ratio of main signal turning left to green, λ _I , is 0.25; the starting time of the main signal turning left to red light at the south entrance , r _I ', take 20s; average vehicle speed, v, take 10m/s; minimum vehicle speed, v _min , take 6m/s; queuing dissipation wave velocity, v _w , take 4.5m/s; d, take 7m; safe time interval, δ, take 2s.

Table 1

The specific process is briefly described as follows:

Step 1: Substituting the above input parameters into the mathematical programming model established by the present invention.

$\begin{array}{cc}\mathrm{<span\; class="notranslate">\; max</span>}& \mathrm{<span\; class="notranslate">\; 1600</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}\\ \mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; .</span>& \mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 1800</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 1600</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; /</span><span\; class="notranslate">\; \&lsqb;</span>\mathrm{<span\; class="notranslate">\; 3600</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1800</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1600</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&rsqb;</span>\\ & {\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 20</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\\ & \mathrm{<span\; class="notranslate">\; 1800</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 0.25</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 1600</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}\\ & \mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 0.25</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 120</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\\ & {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 120</span>}\\ & {\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}\\ & {\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ & {\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 4.5</span>}\\ & \mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 0</span>}\end{array}$

Step 2: The above model is a linear programming model, which can be solved by simplex method or optimization problem solving software (such as LINGO). The optimization result is that the position of the pre-stop line is set at L=72.0m away from the intersection stop line, the pre-signal period length (C _p ) is 120s, the start time of the pre-signal green light (g _p ) is 50s, and the pre-signal green signal ratio (λ _p ) is 0.21.

Step 3: Design proposal evaluation. Taking traffic capacity as an evaluation index, the traditional design scheme and the improved scheme of the present invention are compared. The traffic capacity of each lane group at the intersection is shown in formula (11). In the traditional design scheme, the distance between the pre-stop line and the intersection stop line refers to the length of the widening section in the "Urban Road Intersection Planning Specification GB50647-2011", and the pre-signal timing is the same as that of the left-turn signal at the west entrance of the intersection.

c _i =s _i n _i λ _i (11)

In the formula _{: ci is the traffic capacity of each lane group at the intersection, veh/h; s i is} the saturated flow rate of each lane group at the intersection, which is uniformly taken as 1800veh/h; n _i is the number of lanes in each lane group at the intersection; _λi is the green signal ratio of each flow direction at the intersection.

As shown in table 2, according to the method of the present invention, the pre-stop line position and the pre-signal timing of the west entrance by way of the left-turn lane are optimized, so that the present embodiment can keep the traffic capacity of other lane groups at the intersection unchanged. Under the above circumstances, the traffic capacity of the left-turn lane at the west entrance is increased by 57.7%, and the total traffic capacity of this flow direction is increased by 18.6%, so that the traffic efficiency of the left-turn intersection has been fully utilized.

Table 2

The above description of the embodiments is for those of ordinary skill in the art to understand and apply the present invention. It is obvious that those skilled in the art can easily make various modifications to this embodiment, and apply the general principles described here to other embodiments without creative efforts. Therefore, the present invention is not limited to the embodiments herein. Improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims (2)

1. A method for setting up a pre-stop line and a pre-signal at a left-turn intersection, characterized in that: the key parameters of the unique pre-stop line and pre-signal settings at a left-turn intersection are integrated in a unified optimization model , to carry out synchronous optimization, so as to improve the traffic capacity on the basis of ensuring traffic safety. The optimization model is expressed by a linear programming model, with the maximum traffic capacity as the optimization goal, and considering the constraints of queue length, vehicle emptying and the value range of optimization parameters. in: The input parameters of the optimization model include: sp , the saturated flow rate of entering the left-turn lane at the pre-stop line, _veh /h; s _I , the saturated flow rate of the left-turn lane at the intersection stop line, veh/h; n, the number of left-turning lanes, C _I , the cycle duration of the main signal, s; g _I , the starting time of the green light of the main signal turning left, s; λ _I , the green signal ratio of the main signal turning left; r ′ _I , the starting time of the main signal of the entrance on the right side of the studied entrance turning left at the red light, s; v, the average vehicle speed, m/s; _{v min} , the minimum vehicle speed, m/s; s; d, average headroom distance of queuing vehicles, m; δ, safety time interval, s; The output parameters of the optimization model include: L, the distance between the pre-stop line and the intersection stop line, m; C _p , the duration of the pre-signal cycle, s; g _p , the start time of the pre-signal green light, s; λ _p , the pre-signal green light letter ratio; The optimization objective function is to maximize the traffic capacity of the left-turn lane, as shown in formula (1); maxs _p λ _p (1) The constraint of the queuing length requires that the length of the left-turning lane should be greater than or equal to the queuing length of the left-turning vehicle entering the lane, which satisfies the requirements of formula (2); $\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; d</span>}}{\mathrm{<span\; class="notranslate">\; 3600</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$ The constraints on the emptying of the vehicle are required to meet the following four constraints: First, the start time of the pre-signal green light should satisfy that all vehicles using the exit have passed the section where the pre-stop line is located, that is, satisfy the requirements of formula (3); ${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; min</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$ Second, the traffic capacity of the left-turning lane at the intersection stop line should be greater than or equal to the traffic capacity of the left-turning lane to ensure that the left-turning vehicles entering the lane can pass through the intersection in the same phase without vehicle stranded , which satisfies the requirement of formula (4); s _I λ _I ≥ s _p λ _p (4) Third, the time interval between the end time of the pre-signal green light and the end time of the corresponding left-turn green light of the main signal should be greater than or equal to the driving time of left-turning vehicles passing through the left-turn lane, so as to ensure that the vehicles entering the left-turn lane at the end of the pre-signal green light Vehicles can also pass through the intersection in this phase, which satisfies the requirements of formula (5); ${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; \&Greater\; Equal;</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$ Fourth, the period length of the main pre-signal at the intersection should be consistent to ensure that the main pre-signal has a good coordinated control effect, that is, to meet the requirements of formula (6); C _I =C _p (6) The value range of the optimization parameters should meet the following four constraints: One is that the optimization parameters are all non-negative, that is, the requirements of formula (7) are met; L,g _p ,λ _p ,C _p ≥0(7) The second is that the start time of the pre-signal green light should not be greater than the cycle duration, which meets the requirements of formula (8); g _p ≤ C _p (8) Third, the pre-signal green-to-signal ratio must not be greater than 1, which satisfies the requirements of formula (9); λ _p ≤ 1(9) Fourth, the end time of the pre-signal effective green light is the moment when the queue of the left-turn lane at the entrance dissipates and reaches the pre-stop line, which satisfies the requirements of formula (10). ${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}}{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$ 2. The pre-stop line and pre-signal setting method at the left-turn intersection according to claim 1, characterized in that: in the above-mentioned optimization process, it is necessary to consider: (1) from the perspective of queuing length constraints, the pre-stop line position setting The farther away from the stop line at the intersection, the better it can accommodate more queuing vehicles; (2) From the perspective of vehicle clearing constraints, the position of the pre-stop line should be set as close as possible to the stop line at the intersection, which can reduce the time for vehicle clearing ; This optimization setting method considers the contradiction between these two aspects, and establishes it in a unified optimization model, so that the traffic efficiency of the intersection design mode of taking the left turn intersection can be fully exerted on the basis of ensuring traffic safety .