A coordinated control method for remote U-turn and shifted left turn at intersection

Abstract

The present invention belongs to the field of urban traffic control technology, and specifically relates to a coordinated control method for remote U-turns and shifted left turns at intersections, comprising step S1: intersection channelization design; step S2: intersection signal design, including the design of intersection main signals and intersection pre-signals; step S3: traffic organization design; step S4: intersection phase sequence design; step S5: determination of the full red time; step S6: determination of pre-signals, including the determination of U-turn pre-signals and shift pre-signals; step S7: determination of the length of the opening from the intersection, including the determination of the minimum length of the shift lane and the minimum length of the U-turn lane. By optimizing signal timing and spatial resource allocation, the coordinated operation of remote U-turns of left-turning vehicles on the secondary road and left turns on the main road via the lane is achieved, thereby improving intersection traffic efficiency and eliminating traffic conflicts.

Description

Technical Field

[0001] The present invention belongs to the technical field of urban traffic control, and in particular relates to a method for coordinated control of remote U-turn and shifted left turn at an intersection. Background Art

[0002] Resolving conflicts among left-turning traffic at intersections is a core challenge in improving traffic efficiency. Existing technologies include Displaced Left Turn (DLT) and Remote U-Turn (RTT). However, their application is limited by road space conditions and technical synergy gaps. The specific technical bottlenecks are as follows:

[0003] 1. Limitations of shifting left,

[0004] Requirements for eight lanes in both directions: Traditional left-turn shifting requires shifting the left-turn lane to the left of the oncoming exit lane. This is generally applicable to eight-lane roads in both directions to provide sufficient space for passing lanes. The US AASHTO standard recommends a lane width of 3.5 meters or greater, and a total width of 28 meters or greater for eight lanes in both directions. However, this method is rarely used in six-lane roads in both directions. Insufficient passing lanes can reduce the speed of oncoming through traffic and increase the probability of collisions.

[0005] Secondary road left turns are not adapted: Existing technologies (such as Chinese patent application CN118747950A) only optimize left-turn traffic on the main road, while secondary road left turns still rely on traditional phase control, resulting in a surge in delays for secondary road left turns. (For example, "An Improved Shifted Left Turn Lane Signal Control Method and Its Utility Analysis" [1]).

[0006] 2. Spatial dependence of remote U-turn,

[0007] Mandatory requirements for central medians and safety islands: Traditional remote U-turns require a fixed opening downstream (Chinese regulations require an opening width of ≥4.25 m for small vehicles and ≥6.5 m for large vehicles) and a safety island to isolate oncoming traffic (for example, the U-turn solution proposed in the “Central Median Opening Spacing for Remote U-turns” [2] requires an independent opening and physical isolation facilities), resulting in high modification costs.

[0008] Path rigidity and efficiency loss: Vehicles turning left on the secondary road must detour to a fixed opening to make a U-turn. The detour distance is usually ≥200 meters, and the fixed path cannot be adjusted according to traffic flow, resulting in frequent interweaving of traffic with vehicles going straight on the main road. In addition, in traditional solutions, the opening needs to be a long distance away from the intersection to ensure that vehicles turning far away can smoothly change lanes one by one to the leftmost lane of the main road. Therefore, vehicles turning left on the secondary road with a U-turn made far away experience high delays (for example, "Intersection Double Ring Phase Reduction Strategy and Analysis of the Impact of Vehicle U-turns Made Far Away" [3]).

[0009] 3. Technical collaboration gap,

[0010] Independent Function Design: Traditionally, shifted left turns and remote U-turns occupy separate spaces (eight lanes in both directions and a central median opening), resulting in fragmented road resources. For example, a shifted left turn requires eight lanes in both directions to accommodate a passing area, while a remote U-turn requires a separate opening and a safety island, preventing the two from sharing space.

[0011] Lack of signal coordination: Existing technologies (e.g., Chinese patent application CN114973703A) do not implement signal linkage between the left turn on the main road and the U-turn on the secondary road, resulting in a temporal and spatial conflict between the two traffic flows in a shared space.

[0012] Therefore, it is urgent to invent a method that can coordinate the two technologies of shifted left turn and remote U-turn at the same intersection and can be adapted to the traffic organization mode of the main road with two-way six lanes.

[0013] [1] Jiang Xiancai, Gao Su, Zhang Longyang. An improved shifted left turn lane signal control method and its effectiveness analysis [J]. China Journal of Highway and Transport, 2019, 32 (09): 152-163. DOI:10.19721 / j.cnki.1001-7372.2019.09.015.

[0014] [2] Zhang Ning, Chen Kai, He Tiejun, et al. Opening spacing of central median strip under remote 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.

[0015] [3] Cao Kefan. Analysis of the impact of double-loop phase reduction strategy and vehicle U-turn at intersections[D]. Nanjing Forestry University, 2023.DOI:10.27242 / d.cnki.gnjlu.2023.000353. Summary of the Invention

[0016] In light of the above-mentioned issues, the present invention aims to provide a method for coordinated control of remote U-turns and shifted left turns at intersections. By employing novel phase planning and road marking design at grade intersections, this method enables the coordinated application of shifted left turns and remote U-turns on a six-lane, bidirectional main road. Furthermore, this method can be used even on roads without a central median, thereby improving intersection capacity. Compared to existing technologies, this method can utilize remote U-turns and shifted left turns on a six-lane, bidirectional road (traditionally, this technology requires at least eight lanes in both directions). Furthermore, this method requires no extensive road surface modification during deployment, requiring only the rearrangement of road markings and the addition of traffic lights.

[0017] The present invention provides a method for coordinated control of remote U-turn and shifted left turn at an intersection, comprising the following steps:

[0018] Step S1: Intersection channelization design, including: the configuration of the central opening of the main road, the configuration of turn signal lights, the configuration of U-turn signal lights, the configuration of lanes for secondary roads, the configuration of lanes for the main road, and the configuration of vehicle guide lines for left turns (remote U-turns) on the secondary roads within the intersection;

[0019] Step S2: Designing intersection signals, including: designing intersection main signals and intersection pre-signals;

[0020] Step S3: Designing traffic organization, including signal control for vehicles going straight on the secondary road, vehicles turning left on the secondary road, vehicles turning right on the secondary road, vehicles turning left on the main road, vehicles going straight on the main road, and vehicles turning right on the main road;

[0021] Step S4: Design the phase sequence of the intersection;

[0022] Step S5: Determination of the all-red time;

[0023] Step S6: determining a pre-signal, including determining a U-turn pre-signal and a shift pre-signal;

[0024] Step S7: determining the distance between the opening and the intersection, including determining the minimum length of the shift lane and the minimum length of the U-turn lane.

[0025] As a preferred embodiment of the present invention, step S1 further includes the following steps:

[0026] Step S1.1: An opening is set up in the center of the main road. Left-turning vehicles on the secondary road that need to make a U-turn and left-turning vehicles on the main road using the shifted left-turn lane complete lane changes in sequence at the opening.

[0027] Step S1.2: Install a turn signal lamp for vehicles turning left on the main road before the opening of the leftmost lane of the main road entrance, where the distance from the opening to the intersection is ;

[0028] Step S1.3: Install a U-turn warning light for vehicles turning left from the secondary road before the rightmost lane opening of the main road exit;

[0029] Step S1.4: Design lanes for the secondary road. Set up a through lane and a right-turn lane at the secondary road entrance. The inner lane of the secondary road entrance is for vehicles going straight, and the outer lane of the secondary road entrance is for vehicles turning left, right, and going straight. If there is only one entrance lane, the secondary road entrance is for vehicles going straight, turning left, and turning right.

[0030] Step S1.5: Design the lanes on the main road. The rightmost lane at the main road exit is for vehicles going straight on the main road and turning left from the secondary road. The leftmost lane and the middle lane at the main road exit are for vehicles going straight on the main road. A U-turn pre-signal light is installed in front of the rightmost lane at the main road exit to control vehicles turning around. A shift pre-signal light is installed in front of the leftmost lane at the main road entrance to control vehicles shifting.

[0031] Step S1.6: Design the guidance line for vehicles turning left (remote U-turn) at the intersection. Set the guidance line for vehicles turning left (remote U-turn) on the secondary road at the intersection to guide vehicles turning left (remote U-turn) on the secondary road into the U-turn lane.

[0032] As a preference of the present invention, step S2 further includes the following steps:

[0033] Step S2.1: Set the main signal of the intersection,

[0034] Step S2.1.1: Setting a secondary road signal to control vehicles going straight on the secondary road;

[0035] Step S2.1.2: Setting a main road straight signal to control vehicles going straight on the main road;

[0036] Step S2.1.3: Set the main road left turn signal to control vehicles turning left on the main road.

[0037] As a preference of the present invention, step S2 further includes the following steps:

[0038] Step S2.2: Set the intersection pre-signal,

[0039] Step S2.2.1: Set a U-turn pre-signal to control whether vehicles turning left on the secondary road can make a U-turn at the opening;

[0040] Step S2.2.2: Set a shift pre-signal to control whether a vehicle turning left from the main road can enter the leftmost lane of the main road exit at the opening.

[0041] As a preference of the present invention, step S3 further includes the following steps:

[0042] Step S3.1: The through-going vehicle on the secondary road is controlled by the secondary road signal and passes through the intersection using the through-going phase of the secondary road;

[0043] Step S3.2: Left-turning vehicles on the secondary road are not controlled by the secondary road signal. They enter the rightmost lane of the main road entrance via the rightmost lane of the secondary road. The rightmost lane of the main road entrance is the U-turn lane. At the entrance, they make a U-turn under the U-turn pre-signal and use the main road's straight-ahead phase to pass through the intersection.

[0044] Step S3.3: The vehicle turning right on the secondary road is not controlled by the secondary road signal and enters the main road lane via the rightmost lane of the secondary road;

[0045] Step S3.4: The vehicle turning left from the main road is controlled by the shift pre-signal and the main road left turn signal and enters the leftmost lane of the main road exit to reach the intersection. The leftmost lane of the main road exit is the shift lane, and the vehicle uses the main road left turn phase to pass through the intersection.

[0046] Step S3.5: The main road through-going vehicle is controlled by the main road through-going signal and passes through the intersection using the main road through-going phase;

[0047] Step S3.6: The vehicle turning right from the main road is not controlled by the main road's straight-ahead signal and enters the lane of the secondary road via the rightmost lane of the main road.

[0048] As a preference of the present invention, step S4 also includes the following steps:

[0049] Step S4.1: Set the first phase as the secondary road straight phase;

[0050] Step S4.2: Set the second phase as the main road left turn phase;

[0051] Step S4.3: Set the third phase as the main road straight phase.

[0052] As a preference of the present invention, step S5 also includes the following steps:

[0053] A full red time is set between the main road through 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 through signal, and the following conditions are met:

[0054] ;

[0055] Where, For all red time, It is the maximum value of the difference between the distance required for the last vehicle to pass the stop line in the current phase to reach the conflict point and the distance required for the first vehicle in each lane of the next phase to reach the conflict point. is the body length, The speed of the vehicle during the green light period.

[0056] As a preference of the present invention, step S6 also includes the following steps:

[0057] Step S6.1: Determination of the U-turn pre-signal,

[0058] A safety interval is set between the end of the green light of the main road through signal and the onset of the green light of the U-turn pre-signal. The U-turn pre-signal is turned on later than the secondary road signal and meets the following requirements:

[0059] ;

[0060] Where, The green light interval time between the end of the green light of the main road through signal and the start of the green light of the U-turn pre-signal, is the distance from the opening to the intersection, The distance that the straight-going vehicles on the main road pass through the intersection, The average speed of the last vehicle from the stop line to the opening at the end of the green light in the previous main road straight phase. For safety interval time.

[0061] As a preference of the present invention, step S6 also includes the following steps:

[0062] Step S6.2: Determination of the shift pre-signal,

[0063] Step S6.2.1: Determine the time difference between the shift pre-signal and the U-turn pre-signal.

[0064] A green light interval is set between the end of the green light of the U-turn pre-signal and the start of the green light of the shift pre-signal. The shift pre-signal is turned on later than the U-turn pre-signal, and the following conditions are met:

[0065] ;

[0066] Where, The green light interval time between the end of the green light of the U-turn pre-signal and the start of the green light of the shift pre-signal. is the length of the U-turn curve at the opening for vehicles turning left on the secondary road. is the speed of the left-turning vehicle passing through the U-turn curve at the opening of the secondary road, For safety interval time;

[0067] Step S6.2.2: Determine the time difference between the shifted pre-signal and the secondary signal.

[0068] A green light utilization time is set between the time when the shift pre-signal turns green and the time when the secondary road signal turns green. The green light utilization time is less than the time it takes for a left-turning vehicle on the main road to drive from the opening to the intersection, that is:

[0069] ;

[0070] Where, 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. The length of the shift curve at the opening for vehicles turning left on the main road, The speed of the left-turning vehicles on the main road passing through the shift curve at the opening, For safety interval time, is the distance from the opening to the intersection;

[0071] Step S6.2.3: Determine the time difference between the shift pre-signal and the main road left turn signal.

[0072] Step S6.2.3.1: Set a green light interval between the moment the shift pre-signal turns green and the moment the main road left turn signal turns green, and the following conditions must be met:

[0073] ;

[0074] Where, The green light interval time between the time when the shift pre-signal turns green and the time when the main road left turn signal turns green. For all red time, It is yellow light time. The green light utilization time between the start time of the green light of the shift pre-signal and the end time of the green light of the secondary road signal;

[0075] Step S6.2.3.2: Set a clearing time between the end of the green light of the main road left turn signal and the end of the green light of the shift pre-signal, and satisfy the following conditions:

[0076] ;

[0077] Where, The clearing time between the end of the green light of the main road left turn signal and the end of the green light of the shift pre-signal, It is the green light utilization time between the moment when the green light of the shift pre-signal turns on and the moment when the green light of the secondary signal ends.

[0078] As a preferred embodiment of the present invention, step S7 further includes the following steps:

[0079] Step S7.1: The minimum length of the shifted lane should satisfy the following formula:

[0080] ;

[0081] Where, is the minimum length of the shift lane, is the vehicle arrival non-uniformity coefficient, is the left-turn traffic volume in one cycle, is the average parking distance;

[0082] ;

[0083] Where, is the left-turn traffic volume in one cycle, For peak hour traffic volume of vehicles turning left on the main road, is the intersection signal cycle time, is the number of lanes in this phase;

[0084] Step S7.2: The minimum length of the U-turn lane should satisfy the following formula:

[0085] ;

[0086] Where, is the minimum length of the U-turn lane, is the vehicle arrival non-uniformity coefficient, is the left-turn traffic volume in one cycle, is the average parking distance;

[0087] ;

[0088] Where, is the left-turn traffic volume in one cycle, The peak hour traffic volume of vehicles turning left on the secondary road is: is the intersection signal cycle time, is the number of lanes in this phase;

[0089] The minimum length of the U-turn lane and the minimum length of the shift lane are selected as the common minimum constraints for the two, namely:

[0090] .

[0091] The beneficial effects of the present invention are as follows:

[0092] 1. The present invention proposes a traffic organization method for intersections that combines remote U-turns and shifted left turns. The method is applicable to intersections between main and secondary roads and can effectively reduce main road delays at intersections where there are serious conflicts between straight and left turns. By optimizing signal timing and spatial resource allocation, the coordinated operation of remote U-turns of vehicles turning left on secondary roads and left turns on the main road via detours can be achieved, thereby improving intersection traffic efficiency and eliminating traffic conflicts.

[0093] 2. The present invention sets up a U-turn waiting area and a shift lane at the main road exit. It uses the time when there are no oncoming straight vehicles entering the exit lane to allocate it to vehicles turning left on the secondary road (remote U-turn) and turning left on the main road (shifted left turn), thereby improving road utilization.

[0094] 3. The present invention eliminates the conflict between the secondary road's straight-going left-turning traffic flow through an intersection traffic organization method that combines remote-guided U-turns and shifted left turns. Two pre-signals are designed, and through signal timing, the conflict between the secondary road's left-turning (remote-guided U-turn) traffic flow and the main road's straight-going traffic flow is eliminated, and the conflict between the secondary road's left-turning (remote-guided U-turn) traffic flow and the main road's left-turning (shifted left turn) traffic flow is eliminated.

[0095] 4. The present invention sets up the same opening for remote U-turn and shifted left turn. By determining the signal timing and the length of the opening from the intersection, the opening position is guaranteed to meet the needs of remote U-turn on the secondary road and shifted left turn on the main road.

[0096] 5. By optimizing the U-turn position of the remote U-turn and adding a U-turn pre-signal, the present invention enables the remote U-turn technology to be applied to a main road with six lanes in both directions and without a central dividing strip, thereby broadening the applicable conditions of the remote U-turn technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0097] By referring to the following description in conjunction with the accompanying drawings, and with a more complete understanding of the present invention, other objects and results of the present invention will become more clear and easy to understand. In the accompanying drawings:

[0098] Figure 1 The intersection channelization design diagram provided by the present invention;

[0099] Figure 2 The intersection signal timing diagram of the present invention;

[0100] Description of the accompanying drawings: secondary road through signal light 1, U-turn pre-signal light 2, shift pre-signal light 3, main road left turn signal light 4, main road through signal light 5, secondary road left-turning vehicles drive along this lane 6, secondary road left-turning vehicles drive along this lane 7, secondary road through signal T1, main road left-turn signal T2, main road through signal T3, U-turn pre-signal T4, shift pre-signal T5. DETAILED DESCRIPTION

[0101] See Figure 1-2 The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0102] An embodiment of the present invention provides a method for coordinated control of remote U-turn and shifted left turn at an intersection, comprising the following steps:

[0103] Step S1: intersection channelization design;

[0104] Step S1.1: An opening is set up in the center of the main road. Left-turning vehicles on the secondary road that need to make a U-turn and left-turning vehicles on the main road using the shifted left-turn lane complete lane changes in sequence at the opening.

[0105] Step S1.2: Install a turn signal lamp for vehicles turning left (shifted left) on the main road before the opening of the leftmost lane of the main road exit. The distance between the opening and the intersection is ;

[0106] Step S1.3: Install a U-turn pre-signal light for vehicles turning left (remote U-turn) on the secondary road before the rightmost lane opening of the main road exit;

[0107] Step S1.4: Design lanes for the secondary road. A through lane and a right-turn lane are provided at the secondary road entrance, but no left-turn lane is provided. The inner lane of the secondary road entrance is for vehicles traveling through the road, and the outer lane of the secondary road entrance is for vehicles turning left, right, and traveling through the road. If there is only one entrance lane to the secondary road, the secondary road entrance is for vehicles traveling through the road, turning left, and turning right.

[0108] Step S1.5: Design the lanes on the main road. The rightmost lane at the main road exit is for vehicles going straight on the main road and turning left (remote U-turns) on the secondary road. The remaining lanes are for vehicles going straight on the main road. A U-turn pre-signal light is installed in front of the rightmost lane at the main road exit to control U-turning vehicles. A shift pre-signal light is installed in front of the leftmost lane at the main road entrance to control shifting vehicles.

[0109] Step S1.6: Design left-turn U-turn vehicle guidance lines within the intersection. Set left-turn U-turn vehicle guidance lines within the intersection to guide vehicles turning left (U-turning) on the secondary road into the left-turn U-turn lane.

[0110] Step S2: designing intersection signals;

[0111] Step S2.1: Set the main signal of the intersection,

[0112] Step S2.1.1: Setting a secondary road signal to control vehicles going straight on the secondary road;

[0113] Step S2.1.2: Setting a main road straight signal to control vehicles going straight on the main road;

[0114] Step S2.1.3: Set the main road left turn signal to control vehicles turning left on the main road.

[0115] Step S2.2: Set the intersection pre-signal,

[0116] Step S2.2.1: Set a U-turn pre-signal to control whether vehicles turning left on the secondary road can make a U-turn at the opening;

[0117] Step S2.2.2: Set a shift pre-signal to control whether a vehicle turning left from the main road can enter the leftmost lane of the main road exit at the opening.

[0118] Step S3: Design traffic organization;

[0119] Step S3.1: The through-going vehicle on the secondary road is controlled by the secondary road signal and passes through the intersection using the through-going phase of the secondary road;

[0120] Step S3.2: Left-turning vehicles on the secondary road are not controlled by the secondary road signal. They enter the rightmost lane of the main road entrance via the rightmost lane of the secondary road. The rightmost lane of the main road entrance is the U-turn lane. At the entrance, they make a U-turn under the U-turn pre-signal and use the main road's straight-ahead phase to pass through the intersection.

[0121] Step S3.3: The vehicle turning right on the secondary road is not controlled by the secondary road signal and enters the main road lane via the rightmost lane of the secondary road;

[0122] Step S3.4: The vehicle turning left from the main road is controlled by the shift pre-signal and the main road left turn signal and enters the leftmost lane of the main road exit to reach the intersection. The leftmost lane of the main road exit is the shift lane, and the vehicle uses the main road left turn phase to pass through the intersection.

[0123] Step S3.5: The main road through-going vehicle is controlled by the main road through-going signal and passes through the intersection using the main road through-going phase;

[0124] Step S3.6: The vehicle turning right from the main road is not controlled by the main road's straight-ahead signal and enters the lane of the secondary road via the rightmost lane of the main road.

[0125] Step S4: Design the phase sequence of the intersection;

[0126] Step S4.1: Set the first phase as the secondary road straight phase;

[0127] Step S4.2: Set the second phase as the main road left turn phase;

[0128] Step S4.3: Set the third phase as the main road straight phase.

[0129] Step S5: Determination of the all-red time;

[0130] A full red time is set between the main road through 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 through signal, and the following conditions are met:

[0131] ;

[0132] Where, Full red time (s), The maximum value (m) of the difference between the distance required for the last vehicle to pass the stop line in the current phase to reach the conflict point and the distance required for the first vehicle in each lane in the next phase to reach the conflict point. is the vehicle body length (m), is the vehicle's speed during the green light period (m / s).

[0133] Step S6: determining the pre-signal;

[0134] Step S6.1: Determination of the U-turn pre-signal,

[0135] Since the left-turning vehicles on the secondary road must avoid conflicts with the main road through-going vehicles in the previous main road through-going phase when turning around at the opening, a safety interval needs to be set between the end of the green light of the main road through-going signal and the onset of the green light of the U-turn pre-signal. The safety interval must ensure that the main road through-going vehicles that have passed the stop line at the end of the previous main road through-going phase have completely passed through the area before the opening before the left-turning vehicles on the secondary road can start turning around. Therefore, the U-turn pre-signal must be turned on later than the secondary road signal and meet the following requirements:

[0136] ;

[0137] Where, The green light interval time (s) between the end of the green light of the main road through signal and the start of the green light of the U-turn pre-signal. is the distance from the opening to the intersection (m), The distance that the straight-going vehicles on the main road pass through the intersection (m), The average speed (m / s) of the last vehicle from the stop line to the opening at the end of the green light in the previous main road straight phase. is the safety interval time (s);

[0138] Step S6.2: Determination of the shift pre-signal,

[0139] Step S6.2.1: Determine the time difference between the shift pre-signal and the U-turn pre-signal.

[0140] Since left-turning vehicles on the main road must avoid conflicts with vehicles on the secondary road turning left at the opening when entering the shift lane, a green light interval is required between the end of the green light of the U-turn pre-signal and the onset of the green light of the shift pre-signal. The green light interval should ensure that the last left-turning vehicle on the secondary road completes its U-turn at the opening before the main road left-turning vehicle can begin to enter the shift lane. Therefore, the shift pre-signal should be on later than the U-turn pre-signal and meet the following requirements:

[0141] ;

[0142] Where, The green light interval time (s) between the end of the green light of the U-turn pre-signal and the start of the green light of the shift pre-signal. is the length of the U-turn curve at the opening for vehicles turning left on the secondary road (m), is the speed of the left-turning vehicle on the secondary road passing through the U-turn curve at the opening (m / s), is the safety interval time (s);

[0143] Step S6.2.2: Determine the time difference between the shifted pre-signal and the secondary signal.

[0144] Since it takes a certain amount of time for vehicles turning left from the main road to drive from the opening to the intersection, in order to improve the utilization efficiency of the intersection, a green light utilization time is set between the time when the shift pre-signal turns green and the time when the secondary road signal turns green. This green light utilization time should be less than the time it takes for vehicles turning left from the main road to drive from the opening to the intersection, that is:

[0145] ;

[0146] Where, The green light utilization time (s) between the start time of the shift pre-signal green light and the end time of the secondary road signal green light, The length of the shift curve at the opening for vehicles turning left on the main road (m), The speed of the left-turning vehicle on the main road passing through the shift curve at the opening (m / s), is the safety interval time (s), ;

[0147] Step S6.2.3: Determine the time difference between the shift pre-signal and the main road left turn signal.

[0148] Step S6.2.3.1: Since it takes a certain amount of time for vehicles turning left from the main road to reach the intersection from the opening, in order to avoid conflicts between vehicles turning left from the main road and vehicles going straight on the secondary road at the intersection, a green light interval is set between the time when the shift pre-signal turns green and the time when the main road left turn signal turns green, and the following conditions must be met:

[0149] ;

[0150] Where, The green light interval time (s) between the moment when the shift pre-signal turns green and the moment when the main road left turn signal turns green. For all red time, It is yellow light time. The green light utilization time (s) between the start time of the green light of the shift pre-signal and the end time of the green light of the secondary road signal;

[0151] Step S6.2.3.2: Since it takes time for vehicles turning left from the main road to reach the intersection from the opening, a clearing time must be set between the end of the main road left turn signal and the end of the green light of the shifted lane. This time must meet the following requirements:

[0152] ;

[0153] Where, The clearing time (s) between the end of the green light of the main road left turn signal and the end of the green light of the shift pre-signal. It is the green light utilization time (s) between the moment when the green light of the shift pre-signal turns on and the moment when the green light of the secondary signal ends.

[0154] Step S7: determining the distance between the opening and the intersection, including determining the minimum length of the shift lane and the minimum length of the U-turn lane.

[0155] While the shifted lanes meet the needs of left-turning vehicles, they must also consider the disadvantages of being too long or too short. Since the shifted lanes are located on the main road, if they are too long, the following vehicles may not be able to pass during the green light, while if they are too short, vehicles turning left from the main road will have to wait in a second queue at the pre-signal.

[0156] Step S7.1: The minimum length of the shifted lane should satisfy the following formula:

[0157] ;

[0158] Where, is the minimum length of the shifted lane (m), is the vehicle arrival non-uniformity coefficient, which usually ranges from 1.5 to 2. is the traffic volume of left-turn vehicles in one cycle (vehicles), is the average parking distance, which is calculated based on the weighted content of different types of vehicles. According to actual survey data, the number of large vehicles turning left is less than 2%. If all vehicles are cars, the default value is 7.6m.

[0159] ;

[0160] Where, is the traffic volume of left-turn vehicles in one cycle (vehicles), Peak hour traffic volume 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;

[0161] Step S7.2: The minimum length of the U-turn lane should satisfy the following formula:

[0162] ;

[0163] Where, is the minimum length of the U-turn lane (m), is the vehicle arrival non-uniformity coefficient, which usually ranges from 1.5 to 2. is the traffic volume of left-turn vehicles in one cycle (vehicles), is the average parking distance, which is calculated based on the weighted content of different types of vehicles. According to actual survey data, the number of large vehicles turning left is less than 2%. If all vehicles are cars, the default value is 7.6m.

[0164] ;

[0165] Where, is the traffic volume of left-turn vehicles in one cycle (vehicles), is the peak hour traffic volume 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;

[0166] In order to facilitate pre-signal control, the minimum length of the U-turn lane and the minimum length of the shift lane (the larger of the minimum values) are selected as the common minimum constraint for the two, namely:

[0167] .

[0168] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A coordinated control method for remote U-turn and shifted left turn at an intersection, characterized in that: The following steps are involved: Step S1: Intersection channelization design, including: setting the central opening of the main road, setting the turn signal lights, setting the U-turn signal lights, setting the lanes for the secondary road, setting the lanes for the main road, and setting the guide line for left-turn vehicles on the secondary road within the intersection; Step S2: Designing intersection signals, including: designing intersection main signals and intersection pre-signals; Step S3: Designing traffic organization, including signal control for vehicles going straight on the secondary road, vehicles turning left on the secondary road, vehicles turning right on the secondary road, vehicles turning left on the main road, vehicles going straight on the main road, and vehicles turning right on the main road; Step S4: Design the phase sequence of the intersection; Step S5: Determination of the all-red time; Step S6: determining a pre-signal, including determining a U-turn pre-signal and a shift pre-signal; Step S6.1: Determination of the U-turn pre-signal, A safety interval is set between the end of the green light of the main road through signal and the onset of the green light of the U-turn pre-signal. The U-turn pre-signal is turned on later than the secondary road signal and meets the following requirements: ； Where, The green light interval time between the end of the green light of the main road through signal and the start of the green light of the U-turn pre-signal, is the distance from the opening to the intersection, The distance that the straight-going vehicles on the main road pass through the intersection, The average speed of the last vehicle from the stop line to the opening at the end of the green light in the previous main road straight phase. For safety interval time; Step S6.2: Determination of the shift pre-signal, Step S6.2.1: Determine the time difference between the shift pre-signal and the U-turn pre-signal. A green light interval is set between the end of the green light of the U-turn pre-signal and the start of the green light of the shift pre-signal. The shift pre-signal is turned on later than the U-turn pre-signal, and the following conditions are met: ； Where, The green light interval time between the end of the green light of the U-turn pre-signal and the start of the green light of the shift pre-signal. is the length of the U-turn curve at the opening for vehicles turning left on the secondary road. is the speed of the left-turning vehicle passing through the U-turn curve at the opening of the secondary road, For safety interval time; Step S6.2.2: Determine the time difference between the shifted pre-signal and the secondary signal. A green light utilization time is set between the time when the shift pre-signal turns green and the time when the secondary road signal turns green. The green light utilization time is less than the time it takes for a left-turning vehicle on the main road to drive from the opening to the intersection, that is: ； Where, 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. The length of the shift curve at the opening for vehicles turning left on the main road, The speed of the left-turning vehicles on the main road passing through the shift curve at the opening, For safety interval time, is the distance from the opening to the intersection; Step S6.2.3: Determine the time difference between the shift pre-signal and the main road left turn signal. Step S6.2.3.1: Set a green light interval between the moment the shift pre-signal turns green and the moment the main road left turn signal turns green, and the following conditions must be met: ； Where, The green light interval time between the time when the shift pre-signal turns green and the time when the main road left turn signal turns green. For all red time, It is yellow light time. The green light utilization time between the start time of the green light of the shift pre-signal and the end time of the green light of the secondary road signal; Step S6.2.3.2: Set a clearing time between the end of the green light of the main road left turn signal and the end of the green light of the shift pre-signal, and satisfy the following conditions: ； Where, The clearing time between the end of the green light of the main road left turn signal and the end of the green light of the shift pre-signal, The green light utilization time between the start time of the green light of the shift pre-signal and the end time of the green light of the secondary road signal; Step S7: determining the distance between the opening and the intersection, including determining the minimum length of the shift lane and the minimum length of the U-turn lane.

2. The method for coordinated control of remote U-turn and shifted left turn at an intersection according to claim 1, characterized in that: Step S1 also includes the following steps: Step S1.1: An opening is set up in the center of the main road. Left-turning vehicles on the secondary road that need to make a U-turn and left-turning vehicles on the main road using the shifted left-turn lane complete lane changes in sequence at the opening. Step S1.2: Install a turn signal lamp for vehicles turning left on the main road before the opening of the leftmost lane of the main road entrance, where the distance from the opening to the intersection is ; Step S1.3: Install a U-turn warning light for vehicles turning left from the secondary road before the rightmost lane opening of the main road exit; Step S1.4: Design lanes for the secondary road. Set up a through lane and a right-turn lane at the secondary road entrance. The inner lane of the secondary road entrance is for vehicles going straight, and the outer lane of the secondary road entrance is for vehicles turning left, right, and going straight. If there is only one entrance lane, the secondary road entrance is for vehicles going straight, turning left, and turning right. Step S1.5: Design the lanes on the main road. The rightmost lane at the main road exit is for vehicles going straight on the main road and turning left from the secondary road. The leftmost lane and the middle lane at the main road exit are for vehicles going straight on the main road. A U-turn pre-signal light is installed in front of the rightmost lane at the main road exit to control vehicles turning around. A shift pre-signal light is installed in front of the leftmost lane at the main road entrance to control vehicles shifting. Step S1.6: Design a left-turn U-turn vehicle guide line within the intersection. Set a left-turn U-turn vehicle guide line within the intersection to guide left-turn U-turn vehicles into the left-turn U-turn lane.

3. The method for coordinated control of remote U-turn and shifted left turn at an intersection according to claim 1, characterized in that: Step S2 also includes the following steps: Step S2.1: Set the main signal of the intersection, Step S2.1.1: Setting a secondary road signal to control vehicles going straight on the secondary road; Step S2.1.2: Setting a main road straight signal to control vehicles going straight on the main road; Step S2.1.3: Set the main road left turn signal to control vehicles turning left on the main road.

4. The method for coordinated control of remote U-turn and shifted left turn at an intersection according to claim 3, characterized in that: Step S2 also includes the following steps: Step S2.2: Set the intersection pre-signal, Step S2.2.1: Set a U-turn pre-signal to control whether vehicles turning left on the secondary road can make a U-turn at the opening; Step S2.2.2: Set a shift pre-signal to control whether a vehicle turning left from the main road can enter the leftmost lane of the main road exit at the opening.

5. The method for coordinated control of remote U-turn and shifted left turn at an intersection according to claim 1, characterized in that: Step S3 also includes the following steps: Step S3.1: The through-going vehicle on the secondary road is controlled by the secondary road signal and passes through the intersection using the through-going phase of the secondary road; Step S3.2: Left-turning vehicles on the secondary road are not controlled by the secondary road signal. They enter the rightmost lane of the main road entrance via the rightmost lane of the secondary road. The rightmost lane of the main road entrance is the U-turn lane. At the entrance, they make a U-turn under the U-turn pre-signal and use the main road's straight-ahead phase to pass through the intersection. Step S3.3: The vehicle turning right on the secondary road is not controlled by the secondary road signal and enters the main road lane via the rightmost lane of the secondary road; Step S3.4: The vehicle turning left from the main road is controlled by the shift pre-signal and the main road left turn signal and enters the leftmost lane of the main road exit to reach the intersection. The leftmost lane of the main road exit is the shift lane, and the vehicle uses the main road left turn phase to pass through the intersection. Step S3.5: The main road through-going vehicle is controlled by the main road through-going signal and passes through the intersection using the main road through-going phase; Step S3.6: The vehicle turning right from the main road is not controlled by the main road's straight-ahead signal and enters the lane of the secondary road via the rightmost lane of the main road.

6. The method for coordinated control of remote U-turn and shifted left turn at an intersection according to claim 1, characterized in that: Step S4 also includes the following steps: Step S4.1: Set the first phase as the secondary 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. The method for coordinated control of remote U-turn and shifted left turn at an intersection according to claim 1, characterized in that: Step S5 also includes the following steps: A full red time is set between the main road through 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 through signal, and the following conditions are met: ； Where, For all red time, It is the maximum value of the difference between the distance required for the last vehicle to pass the stop line in the current phase to reach the conflict point and the distance required for the first vehicle in each lane of the next phase to reach the conflict point. is the body length, The speed of the vehicle during the green light period.

8. The method for coordinated control of remote U-turn and shifted left turn at an intersection according to claim 1, characterized in that: Step S7 also includes the following steps: Step S7.1: The minimum length of the shifted lane should satisfy the following formula: ； Where, is the minimum length of the shift lane, is the vehicle arrival non-uniformity coefficient, is the left-turn traffic volume in one cycle, is the average parking distance; ； Where, is the left-turn traffic volume in one cycle, For peak hour traffic volume of vehicles turning left on the main road, is the intersection signal cycle time, is the number of lanes in this phase; Step S7.2: The minimum length of the U-turn lane should satisfy the following formula: ； Where, is the minimum length of the U-turn lane, is the vehicle arrival non-uniformity coefficient, is the left-turn traffic volume in one cycle, is the average parking distance; ； Where, is the left-turn traffic volume in one cycle, The peak hour traffic volume of vehicles turning left on the secondary road is: is the intersection signal cycle time, is the number of lanes in this phase; The minimum length of the U-turn lane and the minimum length of the shift lane are selected as the common minimum constraints for the two, namely: 。

Images