Intersection far-leading turn-round and shift left-turn cooperative control method

Abstract

The invention belongs to the technical field of urban traffic control, and particularly relates to an intersection far-leading U-turn and shift left-turn cooperative control method, which comprises the steps of S1, intersection channelization design; s2, designing intersection signals, including designing an intersection main signal and an intersection pre-signal; s3, designing a traffic organization; s4, designing a phase sequence of an intersection phase; step S5, determining full red time; s6, determining pre-signals, including determining a turning-around pre-signal and a shifting pre-signal; and step S7, determining the length from the opening to the intersection, including determining the minimum value of the length of the shift lane and the minimum value of the length of the turn-round lane. By optimizing signal timing and space resource allocation, cooperative operation of far-guiding turning-around of left-turning vehicles on the secondary road and tailgating left-turning of the main road is achieved, the passing efficiency of the intersection is improved, and traffic conflicts are eliminated.

Description

Technical Field

[0001] The present invention belongs to the technical field of urban traffic control, and particularly relates to a cooperative control method for remote U-turn and shifted left-turn at intersections. Background Art

[0002] The conflict resolution of left-turn traffic flow at intersections is the core challenge to improve traffic efficiency. In the prior art, shifted left-turn (DLT) and remote U-turn are two mainstream solutions, but their applications are limited by road space conditions and the lack of technical coordination. The specific technical bottlenecks are as follows: 1. Limitations of shifted left-turn Requirements for two-way eight-lane roads: Traditional shifted left-turn requires shifting the left-turn lane to the left side of the oncoming exit lane. It is generally applicable to two-way eight-lane main roads to provide sufficient borrowing space. The American AASHTO standard recommends that the width of each lane ≥ 3.5 meters, and the total width of two-way eight-lane roads ≥ 28 meters. However, this method is rarely used on two-way six-lane roads. Insufficient borrowing areas will lead to a decrease in the speed of oncoming through traffic and an increase in conflict probability.

[0003] Incompatibility of left-turn on the secondary road: The prior art (such as Chinese Patent Application CN118747950A) only optimizes the left-turn traffic flow on the main road. The left-turn on the secondary road still relies on traditional phase control, resulting in a significant increase in left-turn delay on the secondary road. (Such as "An Improved Signal Control Method for Shifted Left-Turn Lanes and Its Utility Analysis" [1]).

[0004] 2. Spatial dependence of remote U-turn Mandatory requirements for median strips and safety islands: Traditional remote U-turn requires setting a fixed opening downstream (the Chinese specification requires that the opening width for small cars ≥ 4.25 meters, and for large cars ≥ 6.5 meters) and equipping a safety island to isolate oncoming traffic. (For example, the U-turn scheme proposed in "The Spacing of Median Strip Openings under the Remote U-Turn Method" [2] requires independent openings and physical isolation facilities), resulting in high renovation costs.

[0005] Rigid path and efficiency loss: Left-turn vehicles on the secondary road need to detour to a fixed opening for U-turn. The detour distance is usually ≥ 200 meters, and the fixed path cannot be adjusted according to traffic flow, resulting in frequent weaving of traffic flow and oncoming straight-through vehicles on the main road. And in the traditional scheme, the opening needs to be at a relatively long distance from the intersection to ensure that remote U-turn vehicles can smoothly change lanes one by one to the leftmost lane of the main road. Therefore, the left-turn delay of remote U-turn vehicles on the secondary road is relatively high. (Such as "Analysis of the Double-Ring Phase Reduction Strategy at Intersections and the Impact of Vehicle Remote U-Turn" [3]).

[0006] 3. Lack of technical coordination Independent function design: In traditional solutions, the shifted left turn and the far-reaching U-turn each require independent space resources (two-way eight-lane and median opening), resulting in fragmented road resources. For example, the shifted left turn requires a two-way eight-lane to accommodate the borrowing lane, while the far-reaching U-turn requires an additional opening and safety island, and the two cannot share space.

[0007] Lack of signal coordination: Existing technologies (such as Chinese Patent Application CN114973703A) have not achieved signal linkage between the shifted left turn on the main road and the far-reaching U-turn on the secondary road, resulting in spatio-temporal conflicts between the two vehicle flows in the shared space.

[0008] Therefore, there is an urgent need to invent a technology that can synergistically apply the two technologies of shifted left turn and far-reaching U-turn to the same intersection and can adapt to the traffic organization method with a two-way six-lane main road.

[0009] [1] Jiang Xiancai, Gao Su, Zhang Longyang. An improved signal control method for shifted left-turn lanes and its utility analysis [J]. China Journal of Highway and Transport, 2019, 32 (09): 152-163. DOI: 10.19721 / j.cnki.1001-7372.2019.09.015.

[0010] [2] Zhang Ning, Chen Kai, He Tiejun, etc. Median opening spacing under the far-reaching U-turn mode [J]. Journal of Chang'an University (Natural Science Edition), 2009, 29 (01): 78-82. DOI: 10.19721 / j.cnki.1671-8879.2009.01.017.

[0011] [3] Cao Kefan. Analysis of the double-loop phase reduction strategy at intersections and the impact of far-reaching U-turns on vehicles [D]. Nanjing Forestry University, 2023. DOI: 10.27242 / d.cnki.gnjlu.2023.000353. Summary of the Invention

[0012] In view of the above problems, the purpose of the present invention is to provide a coordinated control method for far-reaching U-turn and shifted left turn at intersections. By adopting a new phase plan and pavement marking design at plane intersections, the two technologies of shifted left turn and far-reaching U-turn can be synergistically applied under the condition of a two-way six-lane main road, and it can be used without a median on the main road, improving the traffic capacity of the intersection. Compared with existing technologies, this method can apply the far-reaching U-turn technology and the shifted left turn technology under the condition of a two-way six-lane (the application condition of this technology in the traditional situation is at least a two-way eight-lane); and this method does not require large-scale transformation of the road surface during the layout process, only requires re-arranging the pavement markings and adding signal lights.

[0013] A collaborative control method for far - away U - turn and shifted left - turn at intersections provided by the present invention includes the following steps: Step S1: Channelization design of the intersection, including: setting an opening at the central position of the main road, setting a pre - signal for turning, setting a pre - signal for U - turn, setting lanes in the secondary road direction, setting lanes in the main road direction, and setting a guiding line for left - turning (far - away U - turn) vehicles in the secondary road within the intersection; Step S2: Design of intersection signals, including: design of the main signal and pre - signal of the intersection; Step S3: Design of traffic organization, including: signal control of straight - through vehicles in the secondary road, left - turning vehicles in the secondary road, right - turning vehicles in the secondary road, left - turning vehicles in the main road, straight - through vehicles in the main road, and right - turning vehicles in the main road; Step S4: Design of intersection phases and phase sequences; Step S5: Determination of all - red time; Step S6: Determination of pre - signals, including: determination of U - turn pre - signals and shifted pre - signals; Step S7: Determination of the length from the opening to the intersection, including: determination of the minimum length of the shifted lane and the minimum length of the U - turn lane.

[0014] As a preference of the present invention, the following steps are further included in step S1: Step S1.1: Set an opening at the central position of the main road. Left - turning vehicles in the secondary road that need to make a far - away U - turn and left - turning vehicles in the main road using the shifted left - turn lane complete lane changes in sequence at the opening; Step S1.2: Set a pre - signal for left - turning vehicles in the main road in front of the left - most lane opening of the main road approach. Among them, the distance from the opening to the intersection is ; Step S1.3: Set a pre - signal for U - turn for left - turning vehicles in the secondary road in front of the right - most lane opening of the main road exit; Step S1.4: Design of lanes in the secondary road direction. Set a straight - through lane and a right - turn lane at the secondary road approach. Among them, the inner lane of the secondary road approach is for straight - through vehicles, and the outer lane of the secondary road approach is for left - turning, right - turning, and straight - through vehicles; When there is only one approach lane for the secondary road, the secondary road approach is for straight - through, left - turning, and right - turning vehicles; Step S1.5: Design of lanes in the main road direction. The right - most lane of the main road exit is for main road straight - through and secondary road left - turning vehicles. The left - most lane and the middle lane of the main road exit are for main road straight - through vehicles. Among them, a U - turn pre - signal for controlling U - turn vehicles is set in front of the opening of the right - most lane of the main road exit; A shifted pre - signal for controlling shifted vehicles is set in front of the opening of the left - most lane of the main road approach; Step S1.6: Design of the guiding line for left-turning vehicles with a long-distance U-turn within the intersection. Set the guiding line for left-turning (long-distance U-turn) vehicles on the secondary road within the intersection to guide the left-turning (long-distance U-turn) vehicles on the secondary road into the U-turn lane.

[0015] As a preference of the present invention, the following steps are further included in step S2: Step S2.1: Set the main signal of the intersection. Step S2.1.1: Set the signal for the secondary road to control the straight-going vehicles on the secondary road. Step S2.1.2: Set the straight-going signal for the main road to control the straight-going vehicles on the main road. Step S2.1.3: Set the left-turn signal for the main road to control the left-turning vehicles on the main road.

[0016] As a preference of the present invention, the following steps are further included in step S2: Step S2.2: Set the pre-signal of the intersection. Step S2.2.1: Set the U-turn pre-signal to control whether the left-turning vehicles on the secondary road can make a U-turn at the opening. Step S2.2.2: Set the shift pre-signal to control whether the left-turning vehicles on the main road can drive into the leftmost lane of the main road exit lane at the opening.

[0017] As a preference of the present invention, the following steps are further included in step S3: Step S3.1: The straight-going vehicles on the secondary road are controlled by the signal of the secondary road and pass through the intersection using the straight-going phase of the secondary road. Step S3.2: The left-turning vehicles on the secondary road are not controlled by the signal of the secondary road. The left-turning vehicles on the secondary road drive into the rightmost lane of the main road entrance lane through the rightmost lane of the secondary road. The rightmost lane of the main road entrance lane is the U-turn lane and makes a U-turn under the control of the U-turn pre-signal at the opening, and passes through the intersection using the straight-going phase of the main road. Step S3.3: The right-turning vehicles on the secondary road are not controlled by the signal of the secondary road and drive into the main road lane through the rightmost lane of the secondary road. Step S3.4: The left-turning vehicles on the main road are controlled by the shift pre-signal and the left-turn signal of the main road, drive into the leftmost lane of the main road exit lane to reach the intersection. The leftmost lane of the main road exit lane is the shift lane and passes through the intersection using the left-turn phase of the main road. Step S3.5: The straight-going vehicles on the main road are controlled by the straight-going signal of the main road and pass through the intersection using the straight-going phase of the main road. Step S3.6: The right-turning vehicles on the main road are not controlled by the straight-going signal of the main road and drive into the secondary road lane through the rightmost lane of the main road.

[0018] As a preference of the present invention, the following steps are further included in step S4: Step S4.1: Set the first phase as the straight-going phase of the secondary road. Step S4.2: Set the second phase as the main road left turn phase; Step S4.3: Set the third phase as the main road straight phase.

[0019] As an optimization of the present invention, the following steps are further included in step S5: Set all-red times between the main road straight signal and the secondary road signal, between the secondary road signal and the main road left turn signal, and between the main road left turn signal and the main road straight signal, and satisfy: ; In the formula, is the all-red time, is the maximum value among the differences between the distance traveled by the last vehicle passing the stop line in the current phase lane to reach the conflict point and the distances traveled by the leading vehicles in each lane of the next phase to reach the conflict point, is the vehicle body length, is the vehicle traveling speed during the green light period.

[0020] As an optimization of the present invention, the following steps are further included in step S6: Step S6.1: Determination of the U-turn pre-signal, Set a safety interval time between the end moment of the main road straight signal green light and the start moment of the U-turn pre-signal green light. The U-turn pre-signal is delayed from the secondary road signal to start, and satisfy: ; In the formula, is the green light interval time between the end moment of the main road straight signal green light and the start moment of the U-turn pre-signal green light, is the distance from the opening to the intersection, is the distance for the main road straight vehicles to pass through the intersection, is the average speed of the last vehicle in the main road straight phase green light end from the stop line to the opening, is the safety interval time.

[0021] As an optimization of the present invention, the following steps are further included in step S6: Step S6.2: Determination of the shift pre-signal, Step S6.2.1: Determination of the time difference between the start times of the shift pre-signal and the U-turn pre-signal, Set a green light interval time between the end moment of the U-turn pre-signal green light and the start moment of the shift pre-signal green light. The shift pre-signal is delayed from the U-turn pre-signal to start, and satisfy: ; In the formula, is the green light interval time between the end moment of the U-turn pre-signal green light and the start moment of the shift pre-signal green light, is the U-turn curve length for the vehicles turning left at the secondary road at the opening, is the speed of the vehicles turning left at the secondary road passing through the U-turn curve at the opening, is the safety interval time; Step S6.2.2: Determination of the start time difference between the shifted pre-signal and the secondary road signal, A green light utilization time is set between the green light start time of the shifted pre-signal and the green light start time of the secondary road signal, and the green light utilization time is less than the time for the main road vehicles turning left to drive from the opening to the intersection, that is: ; In the formula, is the green light utilization time between the green light start time of the shifted pre-signal and the green light end time of the secondary road signal, is the shifted curve length of the main road vehicles turning left at the opening, is the speed of the main road vehicles turning left passing through the shifted curve at the opening, is the safety interval time, is the distance from the opening to the intersection; Step S6.2.3: Determination of the start time difference between the shifted pre-signal and the main road left-turn signal, Step S6.2.3.1: A green light interval time is set between the green light start time of the shifted pre-signal and the green light start time of the main road left-turn signal, and it satisfies: ; In the formula, is the green light interval time between the green light start time of the shifted pre-signal and the green light start time of the main road left-turn signal, is the all-red time, is the yellow light time, is the green light utilization time between the green light start time of the shifted pre-signal and the green light end time of the secondary road signal; Step S6.2.3.2: A clearance time is set between the green light end time of the main road left-turn signal and the green light end time of the shifted pre-signal, and it satisfies: ; In the formula, is the clearance time between the green light end time of the main road left-turn signal and the green light end time of the shifted pre-signal, is the green light utilization time between the green light start time of the shifted pre-signal and the green light end time of the secondary road signal.

[0022] As a preference of the present invention, the following steps are further included in step S7: Step S7.1: The minimum value of the shifted lane length should satisfy the following formula, ; In the formula, is the minimum value of the length of the shift lane, is the coefficient of non-uniform vehicle arrival, is the traffic volume of left-turning vehicles within one cycle, is the average stopping spacing; ; In the formula, is the traffic volume of left-turning vehicles within one cycle, is the peak-hour traffic volume of left-turning vehicles on the main road, is the intersection signal cycle time, is the number of lanes in this phase; Step S7.2: The minimum value of the length of the U-turn lane should satisfy the following formula, ; In the formula, is the minimum value of the length of the U-turn lane, is the coefficient of non-uniform vehicle arrival, is the traffic volume of left-turning vehicles within one cycle, is the average stopping spacing; ; In the formula, is the traffic volume of left-turning vehicles within one cycle, is the peak-hour traffic volume of left-turning vehicles on the secondary road, is the intersection signal cycle time, is the number of lanes in this phase; Select the minimum value of the length of the U-turn lane and the minimum value of the length of the shift lane as the common minimum value constraint for both, that is: .

[0023] The beneficial effects of the present invention are as follows: 1. The present invention proposes an intersection traffic organization method that combines far U-turn and shift left-turn, which is applicable to the intersection of the main road and the secondary road. It can effectively reduce the delay of the main road at intersections with serious straight-left conflicts; by optimizing signal timing and spatial resource allocation, it realizes the coordinated operation of the far U-turn of left-turning vehicles on the secondary road and the borrowed left-turn on the main road, improves the intersection traffic efficiency and eliminates traffic conflicts.

[0024] 2. The present invention simultaneously sets a U-turn waiting area and a shift lane at the main road exit lane, and uses the time when there are no oncoming straight vehicles entering the exit lane to allocate it to the left-turning vehicles on the secondary road (far U-turn) and the left-turning vehicles on the main road (shift left-turn) to pass, improving the road utilization rate.

[0025] 3. The traffic organization method at the intersection of the present invention combines far - away U - turn and shifted left - turn, eliminating the conflict of the through - straight and left - turn traffic flows on the secondary road. Two pre - signals are designed, and through signal timing, the conflicts between the left - turn (far - away U - turn) traffic flow on the secondary road and the through - straight traffic flow on the main road, and between the left - turn (far - away U - turn) traffic flow on the secondary road and the left - turn (shifted left - turn) traffic flow on the main road are eliminated.

[0026] 4. The present invention sets the same opening for far - away U - turn and shifted left - turn. By determining the signal timing and the length of the opening from the intersection, it ensures that the opening position meets the requirements of far - away U - turn on the secondary road and shifted left - turn on the main road.

[0027] 5. By optimizing the U - turn position of the far - away U - turn and adding a U - turn pre - signal, the far - away U - turn technology can be applied when the main road has six lanes in both directions and no median strip, broadening the applicable conditions of the far - away U - turn technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] By referring to the following description in conjunction with the drawings, and with a more comprehensive understanding of the present invention, other objects and results of the present invention will become more apparent and easier to understand. In the drawings: Figure 1 is the channelization design drawing of the intersection provided by the present invention; Figure 2 is the signal timing diagram of the intersection of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS: Through - straight signal light 1 on the secondary road, U - turn pre - signal light 2, shifted pre - signal light 3, left - turn signal light 4 on the main road, through - straight signal light 5 on the main road, left - turn vehicles on the secondary road drive along this lane 6, left - turn vehicles on the secondary road drive along this lane 7, through - straight signal T1 on the secondary road, left - turn signal T2 on the main road, through - straight signal T3 on the main road, U - turn pre - signal T4, shifted pre - signal T5. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Refer to Figure 1-2 , the following further describes the present invention in detail with reference to the drawings and specific embodiments.

[0030] The embodiment of the present invention provides a coordinated control method for far - away U - turn and shifted left - turn at an intersection, including the following steps: Step S1: Channelization design of the intersection; Step S1.1: Set an opening at the central position of the main road. The left - turn vehicles on the secondary road that need to make a far - away U - turn and the left - turn vehicles on the main road using the shifted left - turn lane complete lane - changing in sequence at the opening. Step S1.2: Set a steering pre - signal light for the left - turn (shifted left - turn) vehicles on the main road in front of the left - most lane opening of the main road exit lane, where the distance from the opening to the intersection is ; Step S1.3: Set a U-turn pre-signal for the vehicle making a left turn (long-distance U-turn) on the secondary road before the opening of the rightmost lane at the exit of the main road; Step S1.4: Design of the lanes in the secondary road direction. The secondary road approach has a straight lane and a right-turn lane, and no left-turn lane. The inner lane of the secondary road approach is for straight vehicles, and the outer lane is for left-turn, right-turn, and straight vehicles; when there is only one approach lane in the secondary road, the approach lane is for straight, left-turn, and right-turn vehicles; Step S1.5: Design of the lanes in the main road direction. The rightmost lane of the main road exit is for main road straight and secondary road left-turn (long-distance U-turn) vehicles, and the other lanes are for main road straight vehicles. Among them, a U-turn pre-signal for controlling U-turn vehicles is set in front of the opening of the rightmost lane of the main road exit; a shift pre-signal for controlling shift vehicles is set in front of the opening of the leftmost lane of the main road entrance; Step S1.6: Design of the guiding line for left-turn long-distance U-turn vehicles in the intersection. Set a guiding line for left-turn long-distance U-turn vehicles in the intersection to guide the secondary road left-turn (long-distance U-turn) vehicles into the left-turn long-distance U-turn lane.

[0031] Step S2: Design the intersection signals; Step S2.1: Set the main intersection signals, Step S2.1.1: Set the secondary road signals to control the straight vehicles on the secondary road; Step S2.1.2: Set the main road straight signals to control the straight vehicles on the main road; Step S2.1.3: Set the main road left-turn signals to control the left-turn vehicles on the main road.

[0032] Step S2.2: Set the intersection pre-signals, Step S2.2.1: Set the U-turn pre-signals to control whether the secondary road left-turn vehicles can make a U-turn at the opening; Step S2.2.2: Set the shift pre-signals to control whether the main road left-turn vehicles can enter the leftmost lane of the main road exit at the opening.

[0033] Step S3: Design the traffic organization; Step S3.1: The straight vehicles on the secondary road are controlled by the secondary road signals and pass through the intersection using the secondary road straight phase; Step S3.2: The left-turn vehicles on the secondary road are not controlled by the secondary road signals. The secondary road left-turn vehicles enter the rightmost lane of the main road entrance through the rightmost lane of the secondary road. The rightmost lane of the main road entrance is the U-turn lane and is controlled by the U-turn pre-signal at the opening to make a U-turn and pass through the intersection using the main road straight phase; Step S3.3: The right-turn vehicles on the secondary road are not controlled by the secondary road signals and enter the main road lanes through the rightmost lane of the secondary road; Step S3.4: The vehicles turning left on the main road are controlled by the shifted pre-signal and the main road left-turn signal, drive into the leftmost lane of the main road exit lane to reach the intersection. The leftmost lane of the main road exit lane is the shifted lane, and pass through the intersection using the main road left-turn phase; Step S3.5: The vehicles going straight on the main road are controlled by the main road straight-ahead signal and pass through the intersection using the main road straight-ahead phase; Step S3.6: The vehicles turning right on the main road are not controlled by the main road straight-ahead signal and drive into the secondary road lane through the rightmost lane of the main road.

[0034] Step S4: Design the intersection phase sequence; Step S4.1: Set the first phase as the secondary road straight-ahead phase; Step S4.2: Set the second phase as the main road left-turn phase; Step S4.3: Set the third phase as the main road straight-ahead phase.

[0035] Step S5: Determine the all-red time; Set the all-red time between the main road straight-ahead signal and the secondary road signal, between the secondary road signal and the main road left-turn signal, and between the main road left-turn signal and the main road straight-ahead signal, and satisfy: ; In the formula, is the all-red time (s), is the maximum value of the difference between the distance traveled by the vehicle passing the stop line last in this phase lane to reach the conflict point and the distance traveled by the leading vehicle in each lane of the next phase to reach the conflict point (m), is the vehicle body length (m), is the driving speed of the vehicle during the green light period (m / s).

[0036] Step S6: Determine the pre-signal; Step S6.1: Determine the U-turn pre-signal, Since the vehicles turning left on the secondary road need to avoid conflicts with the vehicles going straight on the main road in the previous main road straight-ahead phase when making a U-turn at the opening, a safety interval time needs to be set between the end of the green light of the main road straight-ahead signal and the start of the green light of the U-turn pre-signal. The safety interval time should satisfy that after the vehicles going straight on the main road passing the stop line at the end of the previous main road straight-ahead phase completely pass through the area before the opening, the vehicles turning left on the secondary road can start to make a U-turn. Therefore, the U-turn pre-signal should be delayed to start compared with the secondary road signal and satisfy: ; In the formula, is the green light interval time (s) between the end of the green light of the main road straight-ahead signal and the start of the green light of the U-turn pre-signal, is the distance from the opening to the intersection (m), is the distance (m) for the through vehicles on the main road to pass through the intersection, is the average speed (m / s) of the last vehicle in the main road through phase green light end from the stop line to the opening, is the safety interval time (s); Step S6.2: Determination of the shifted pre-signal, Step S6.2.1: Determination of the time difference between the shifted pre-signal and the U-turn pre-signal lighting time, Since the main road left-turning vehicles need to avoid conflicts with the secondary road left-turning vehicles making U-turns at the opening when entering the shifted lane at the opening, a green light interval time needs to be set between the end of the U-turn pre-signal green light and the start of the shifted pre-signal green light. The green light interval time should ensure that after the last secondary road left-turning vehicle completes a U-turn at the opening, the main road left-turning vehicles can start entering the shifted lane. Therefore, the shifted pre-signal should be delayed from the U-turn pre-signal and satisfy: ; In the formula, is the green light interval time (s) between the end of the U-turn pre-signal green light and the start of the shifted pre-signal green light, is the U-turn curve length (m) of the secondary road left-turning vehicles at the opening, is the speed (m / s) of the secondary road left-turning vehicles passing through the U-turn curve at the opening, is the safety interval time (s); Step S6.2.2: Determination of the time difference between the shifted pre-signal and the secondary road signal lighting time, Since it takes a certain time for the main road left-turning vehicles to drive from the opening to the intersection, to improve the intersection utilization efficiency, a green light utilization time is set between the start of the shifted pre-signal green light and the start of the secondary road signal green light, and it should be such that this green light utilization time is less than the time for the main road left-turning vehicles to drive from the opening to the intersection, that is: ; In the formula, is the green light utilization time (s) between the start of the shifted pre-signal green light and the end of the secondary road signal green light, is the shifted curve length (m) of the main road left-turning vehicles at the opening, is the speed (m / s) of the main road left-turning vehicles passing through the shifted curve at the opening, is the safety interval time (s), ; Step S6.2.3: Determination of the time difference between the shifted pre-signal and the main road left-turn signal lighting time, Step S6.2.3.1: Since it takes a certain amount of time for the vehicles turning left from the main road to reach the intersection from the opening, in order to avoid conflicts between the vehicles turning left from the main road and the vehicles going straight on the secondary road at the intersection, a green interval time needs to be set between the green light start time of the shifted pre-signal and the green light start time of the main road left-turn signal, and it should satisfy: ; In the formula, is the green interval time (s) between the green light start time of the shifted pre-signal and the green light start time of the main road left-turn signal, is the all-red time, is the yellow light time, is the green light utilization time (s) between the green light start time of the shifted pre-signal and the green light end time of the secondary road signal; Step S6.2.3.2: Since it takes a certain amount of time for the vehicles turning left from the main road to reach the intersection from the opening, in order to clear the shifted lane, a clearing time needs to be set between the green light end time of the main road left-turn signal and the green light end time of the shifted pre-signal, and it should satisfy: ; In the formula, is the clearing time (s) between the green light end time of the main road left-turn signal and the green light start time of the shifted pre-signal, is the green light utilization time (s) between the green light start time of the shifted pre-signal and the green light end time of the secondary road signal.

[0037] Step S7: Determination of the length from the opening to the intersection, including: determination of the minimum length of the shifted lane and the minimum length of the U-turn lane.

[0038] On the basis of meeting the demand of left-turning vehicles, the shifted lane needs to consider the adverse factors of being too long or too short. Since the shifted lane is set on the main road, if the shifted lane is too long, it may cause the trailing vehicles unable to pass during the green light, and if it is too short, it will cause the left-turning vehicles on the main road to queue up again at the pre-signal.

[0039] Step S7.1: The minimum length of the shifted lane should satisfy the following formula ; In the formula, is the minimum length of the shifted lane (m), is the vehicle arrival non-uniformity coefficient. Usually, the value range is from 1.5 to 2, is the left-turn vehicle traffic volume in one cycle (vehicles), is the average stopping spacing. The average stopping spacing is calculated by weighted calculation according to the content of different vehicle types. According to the actual survey data, the number of large left-turning vehicles is less than 2%, and it is calculated according to the situation that all are cars, and the default value of 7.6 m is taken.

[0040] ; In the formula, is the traffic volume of left-turning vehicles in one cycle (vehicles), is the peak-hour flow of left-turning vehicles on the main road (pcu / h), is the intersection signal cycle time (s), is the number of lanes in this phase; Step S7.2: The minimum value of the U-turn lane length should satisfy the following formula, ; In the formula, is the minimum value of the U-turn lane length (m), is the non-uniform coefficient of vehicle arrival. Usually, the value range is from 1.5 to 2, is the traffic volume of left-turning vehicles in one cycle (vehicles), is the average stopping spacing. The average stopping spacing is calculated by weighting according to the content of different vehicle types. According to the actual survey data, the number of large vehicles in left-turning vehicles is less than 2%. Calculated according to the situation where all are cars, the default value of 7.6 m is taken.

[0041] ; In the formula, is the traffic volume of left-turning vehicles in one cycle (vehicles), is the peak-hour flow of left-turning vehicles on the secondary road (pcu / h), is the intersection signal cycle time (s), is the number of lanes in this phase; For the convenience of pre-signal control, select the larger value among the minimum values of the U-turn lane length and the shift lane length as the common minimum value constraint for both, that is: .

[0042] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A coordinated control method for far - away U - turn and shifted left - turn at intersections, characterized in that, It includes the following steps: Step S1: Intersection channelization design, including: setting at the opening in the center of the main road, setting of turning pre-signals, setting of U-turn pre-signals, setting of lanes in the secondary road direction, setting of lanes in the main road direction, and setting of guiding lines for left-turning vehicles in the secondary road within the intersection; Step S2: Design of intersection signals, including: design of main intersection signals and pre-signals of the intersection; Step S3: Design of traffic organization, including: signal control of straight-through vehicles in the secondary road, left-turning vehicles in the secondary road, right-turning vehicles in the secondary road, left-turning vehicles in the main road, straight-through vehicles in the main road, and right-turning vehicles in the main road; Step S4: Design of intersection phases and phase sequences; Step S5: Determination of all-red time; Step S6: Determination of pre-signals, including: determination of U-turn pre-signals and shifted pre-signals; Step S7: Determination of the length from the opening to the intersection, including: determination of the minimum length of the shifted lane and the minimum length of the U-turn lane.

2. The coordinated control method for far - away U - turn and shifted left - turn at intersections according to claim 1, wherein, In step S1, it also includes the following steps: Step S1.1: Set an opening in the center of the main road, and the left-turning vehicles in the secondary road that need to make a long U-turn and the left-turning vehicles in the main road using the shifted left-turn lane complete lane changes in sequence at the opening; Step S1.2: A steering pre-signal lamp for the vehicles turning left on the main road is set in front of the opening of the leftmost lane of the main road approach. Herein, the distance between the opening and the intersection is ; Step S1.3: Set a U-turn pre-signal for left-turning vehicles in the secondary road in front of the rightmost lane opening of the main road exit lane; Step S1.4: Design of lanes in the secondary road direction. The straight-through lane and the right-turn lane are set in the secondary road approach lane. Among them, the inner lane of the secondary road approach lane is for straight-through vehicles, and the outer lane of the secondary road approach lane is for left-turning, right-turning, and straight-through vehicles; when there is only one approach lane in the secondary road, the secondary road approach lane is for straight-through, left-turning, and right-turning vehicles; Step S1.5: Design of lanes in the main road direction. The rightmost lane of the main road exit lane is for main road straight-through and secondary road left-turning vehicles, and the leftmost lane and the middle lane of the main road exit lane are for main road straight-through vehicles. Among them, a U-turn pre-signal for controlling U-turn vehicles is set in front of the opening of the rightmost lane of the main road exit lane; a shifted pre-signal for controlling shifted vehicles is set in front of the opening of the leftmost lane of the main road approach lane; Step S1.6: Design of guiding lines for left-turning vehicles with long U-turns within the intersection. Set guiding lines for left-turning vehicles with long U-turns within the intersection to guide left-turning vehicles with long U-turns into the left-turning long U-turn lane.

3. The coordinated control method for far-reaching U-turn and shifted left-turn at intersections according to claim 1, characterized in that, In step S2, it also includes the following steps: Step S2.1: Set main intersection signals, Step S2.1.1: Set secondary road signals for controlling straight-through vehicles in the secondary road; Step S2.1.2: Set main road straight-through signals for controlling straight-through vehicles in the main road; Step S2.1.3: Set main road left-turn signals for controlling left-turning vehicles in the main road.

4. The coordinated control method for far - away U - turn and shifted left - turn at intersections according to claim 3, characterized in that, In step S2, it also includes the following steps: Step S2.2: Set pre-signals of the intersection, Step S2.2.1: Set U-turn pre-signals for controlling whether left-turning vehicles in the secondary road can make a U-turn at the opening; Step S2.2.2: Set shifted pre-signals for controlling whether left-turning vehicles in the main road can enter the leftmost lane of the main road exit lane at the opening.

5. The coordinated control method for far - away U - turn and shifted left - turn at intersections according to claim 1, wherein In step S3, it also includes the following steps: Step S3.1: The vehicles going straight on the minor road are controlled by the minor road signal and pass through the intersection using the minor road straight phase; Step S3.2: The vehicles turning left on the minor road are not controlled by the minor road signal. The vehicles turning left on the minor road drive into the rightmost lane of the main road approach lane through the rightmost lane of the minor road. The rightmost lane of the main road approach lane is the U-turn lane. They make a U-turn under the control of the U-turn pre-signal at the opening and pass through the intersection using the main road straight phase; Step S3.3: The vehicles turning right on the minor road are not controlled by the minor road signal and drive into the main road lane through the rightmost lane of the minor road; Step S3.4: The vehicles turning left on the main road are controlled by the shifted pre-signal and the main road left-turn signal, drive into the leftmost lane of the main road exit lane to reach the intersection. The leftmost lane of the main road exit lane is the shifted lane and pass through the intersection using the main road left-turn phase; Step S3.5: The vehicles going straight on the main road are controlled by the main road straight signal and pass through the intersection using the main road straight phase; Step S3.6: The vehicles turning right on the main road are not controlled by the main road straight signal and drive into the minor road lane through the rightmost lane of the main road.

6. The coordinated control method for far-reaching U-turn and shifted left-turn at intersections according to claim 1, wherein, In step S4, the following steps are further included: Step S4.1: Set the first phase as the minor road straight phase; Step S4.2: Set the second phase as the main road left-turn phase; Step S4.3: Set the third phase as the main road straight phase.

7. A coordinated control method for far-reaching U-turn and shifted left-turn at intersections according to claim 1, characterized in that, In step S5, the following steps are further included: Full red times are set between the main road straight signal and the minor road signal, between the minor road signal and the main road left-turn signal, and between the main road left-turn signal and the main road straight signal, and the following are satisfied: ； In the formula, is the all-red time, is the maximum value among the differences between the distance that the vehicle passing the stop line last in this phase needs to travel to reach the conflict point and the distances that the leading vehicles in each lane of the next phase need to travel to reach the conflict point, is the vehicle body length, is the driving speed of the vehicle during the green light period.

8. A coordinated control method for far-reaching U-turn and shifted left-turn at intersections according to claim 1, characterized in that, In step S6, the following steps are further included: Step S6.1: Determination of the U-turn pre-signal, A safety interval time is set between the end moment of the main road straight signal green light and the start moment of the U-turn pre-signal green light. The U-turn pre-signal starts later than the minor road signal, and the following are satisfied: ； Wherein, is the green light interval time between the end of the green light of the main road straight signal and the start time of the green light of the U-turn pre-signal, is the distance from the opening to the intersection, is the distance that the main road straight vehicles pass through the intersection, is the average speed of the last vehicle at the end of the green light of the previous main road straight phase from the stop line to the opening, is the safety interval time.

9. The coordinated control method for far-reaching U-turn and shifted left-turn at intersections according to claim 8, characterized in that In step S6, the following steps are further included: Step S6.2: Determination of the shifted pre-signal, Step S6.2.1: Determination of the time difference between the start times of the shifted pre-signal and the U-turn pre-signal, A green light interval time is set between the end moment of the U-turn pre-signal green light and the start moment of the shifted pre-signal green light. The shifted pre-signal starts later than the U-turn pre-signal, and the following are satisfied: ； Wherein, is the green light interval time between the end of the U-turn pre-signal green light and the start of the shift pre-signal green light, is the U-turn curve length of the left-turning vehicle on the secondary road at the opening, is the speed of the left-turning vehicle on the secondary road passing through the U-turn curve at the opening, is the safety interval time; Step S6.2.2: Determination of the time difference between the start times of the shifted pre-signal and the minor road signal, A green light utilization time is set between the start moment of the shifted pre-signal green light and the start moment of the minor road signal green light. The green light utilization time is less than the time for the vehicles turning left on the main road to drive from the opening to the intersection, that is: ； In the formula, is the green light utilization time between the start time of the shift pre-signal green light and the end time of the secondary road signal green light, is the shift curve length of the main road left-turning vehicle at the opening, is the speed of the main road left-turning vehicle passing through the shift curve at the opening, is the safety interval time, is the distance from the opening to the intersection; Step S6.2.3: Determination of the time difference between the start times of the shifted pre-signal and the main road left-turn signal, Step S6.2.3.1: A green light interval time is set between the start moment of the shifted pre-signal green light and the start moment of the main road left-turn signal green light, and the following are satisfied: ； In the formula, is the green light interval time between the green light start time of the shift pre-signal and the green light start time of the main road left turn signal, is the all-red time, is the yellow light time, is the green light utilization time between the green light start time of the shift pre-signal and the green light end time of the secondary road signal; Step S6.2.3.2: A clearing time is set between the end moment of the main road left-turn signal green light and the end moment of the shifted pre-signal green light, and the following are satisfied: ； In the formula, is the clearance time between the end time of the green light of the main road left-turn signal and the end time of the green light of the shifted pre-signal, is the green light utilization time between the start time of the green light of the shifted pre-signal and the end time of the green light of the secondary road signal.

10. A coordinated control method for far - away U - turn and shifted left - turn at intersections according to claim 1, characterized in that In step S7, the following steps are further included: Step S7.1: The minimum value of the shifted lane length should satisfy the following formula, ； In the formula, is the minimum value of the length of the shift lane, is the coefficient of non-uniform vehicle arrival, is the traffic volume of left-turning vehicles within one cycle, is the average stopping distance; ； In the formula, is the traffic volume of left-turning vehicles within one cycle, is the peak-hour traffic volume of left-turning vehicles on the main road, is the intersection signal cycle time, is the number of lanes for this phase; Step S7.2: The minimum value of the U-turn lane length should satisfy the following formula, ； In the formula, is the minimum length of the U-turn lane, is the non-uniform coefficient of vehicle arrival, is the traffic volume of left-turning vehicles in one cycle, is the average parking space interval; ； In the formula, is the traffic volume of left-turning vehicles within one cycle, is the peak-hour traffic volume of left-turning vehicles on the minor road, is the intersection signal cycle time, is the number of lanes for this phase; Select the minimum value of the U-turn lane length and the minimum value of the shifted lane length as the common minimum value constraint, that is: 。

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