A full-sensing control method for intersections considering U-turn opening in a connected vehicle environment

Abstract

The present invention belongs to the field of intelligent traffic control technology, and specifically relates to a full-sensing control method for intersections considering U-turn openings in a vehicle networking environment, the steps of which include: for intersections in roads, determining intersection design schemes and parameters, the intersection design schemes and parameters include the intersection channelization scheme, signal phase scheme and virtual stop line position, green light interval time between adjacent phases, and the minimum green light time, maximum green light time and minimum saturation of each phase; analyzing the traffic flow operation characteristics, including the traffic flow operation characteristics during the left turn phase green light and the traffic flow operation characteristics during the straight phase green light; setting a full-sensing control process, including phase control logic and phase termination conditions; calculating the phase green light time involved in the full-sensing control process, and realizing full-sensing control of intersections considering U-turn openings. The present invention can better optimize the signal timing scheme, and the calculated green light time required for the vehicle is more accurate.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent traffic control, and in particular relates to a full-sensing control method for an intersection taking into account U-turn openings in a vehicle networking environment. Background Art

[0002] When conducting intelligent traffic control, the signal timing scheme can be optimized through inductive control methods. Traditional inductive control methods use fixed detectors such as coils, geomagnetism, video, and radar to obtain traffic demand in real time and optimize signal timing schemes in real time. However, coil detectors and geomagnetic detectors can only collect the instantaneous state of the vehicle when it passes through the detection area, and they are easy to damage and have high maintenance costs; video detectors and radar detectors can collect the real-time state of the vehicle in continuous time periods, but their detection accuracy is easily affected by the weather. Therefore, although the traditional inductive control method can respond to changes in traffic demand to a certain extent, there is still much room for improvement. In particular, when the entrance road is equipped with a U-turn opening and a short left-turn lane, U-turn vehicles and left-turn vehicles usually share the left-turn short lane. The queuing and departure of U-turn vehicles are based on the U-turn opening, and the queuing and departure of left-turn vehicles are based on the stop line of the entrance road. In this case, each vehicle detector is unable to obtain the turning requirements of all vehicles in the mixed traffic flow on the left-turn short lane in real time. It can only collect the turning requirements of vehicles leaving the intersection and then infer the turning requirements of vehicles in the mixed traffic flow. Therefore, the obtained data lacks real-time performance, and the limitations of traditional sensing control methods are more obvious at this time.

[0003] The Internet of Vehicles technology can effectively make up for the inherent defects of detectors in traditional induction control methods. In the Internet of Vehicles environment, the steering, position, speed, acceleration and other information of all vehicles can be transmitted to the roadside signal control system in real time. The signal control system can optimize the signal timing plan in real time based on this.

[0004] In general, for intersections with U-turn openings and short left-turn lanes, the research work on existing inductive control methods still has the following shortcomings: when U-turn openings and short left-turn lanes are set on the entrance lanes, the potential impact of the interaction between the U-turn traffic and the traffic in other directions of the same entrance lane and the conflicting traffic on the operation efficiency of the intersection is ignored, and therefore a more detailed control strategy is lacking; many methods are based on specific signal phase schemes, and rarely consider the differentiated impact of different signal phase schemes on the operation laws of traffic flow, and their adaptability is limited. Summary of the invention

[0005] In view of the above deficiencies in the prior art, the present invention provides a full-sensing control method for intersections taking U-turn openings into consideration in a connected vehicle environment. By analyzing the traffic flow operation patterns jointly influenced by U-turn openings, left-turn short lanes and signal phase schemes, and utilizing vehicle steering, position, speed, acceleration and other information obtained in real time in the connected vehicle environment, the signal timing scheme can be better optimized.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is a full-sensing control method for intersections considering U-turn opening in a vehicle networking environment, comprising the following steps:

[0007] S1. For the intersections on the road, determine the intersection design scheme and parameters, which include the intersection channelization scheme, signal phase scheme and virtual stop line position, green light interval between adjacent phases, and the minimum green light time, maximum green light time and minimum saturation of each phase;

[0008] S2. Analyze the traffic flow characteristics, including the traffic flow characteristics during the left turn phase with a green light and the traffic flow characteristics during the straight phase with a green light;

[0009] S3. Based on the traffic flow characteristics analyzed in S2, a full-sensing control process is set, and the full-sensing control process includes phase control logic and phase termination conditions;

[0010] S4. Calculate the phase green light time involved in the full-sensing control process to achieve full-sensing control of the intersection considering U-turn opening.

[0011] As a preferred embodiment of the present invention, in S1, the intersection design scheme and parameters are specifically as follows:

[0012] S11. Channelization scheme: For an entrance road a with a U-turn opening and a left-turn short lane, the stop line is called the actual stop line, and the area between the starting section of the entrance road's left-turn short lane and the actual stop line is called the short lane area. The geometric design parameters of the entrance road include: entrance road number a, number of left-turn lanes M L,a 、Number of straight lanes M T,a 、Number of straight right lanes M TR,a , Number of right turn lanes M R,a , U-turn opening width W U,a , U-turn opening position L a , Turn-around opening length L U,a , left turn short lane length L B,a , W U,a , L a , L U,a , L B,a The unit of is m;

[0013] Among them, the U-turn opening position L a It is the distance between the U-turn opening and the actual stop line;

[0014] S12, signal phase scheme: on the basis of the signal phase scheme of the dual-ring structure (the signal phase scheme designed by NEMA in the known technology can be adopted, and the following description is the supplement and improvement based on this scheme, and NEMA is called National Electrical Manufacturers Association), the U-turn opening is controlled by a dedicated signal, and the U-turn phase follows the current left-turn phase of the entrance lane or the straight-ahead phase of the left entrance lane; if the current left-turn phase of the entrance lane and the straight-ahead phase of the left entrance lane are adjacent, the U-turn phase will continue to light up green during the green light interval between the two phases, that is, the U-turn signal is continuous; otherwise, the U-turn signal is discontinuous; for the left-turn phase or the straight-ahead phase, the phase green light time is divided into the initial green light time and the green light extension time;

[0015] S13, virtual stop line position: when the yellow light is on, if the vehicles near the actual stop line cannot stop safely in front of the actual stop line, they can use the yellow light time to pass the actual stop line; in order to make full use of the green light extension time, when the vehicles in the short lane area pass a certain section upstream of the actual stop line during the green light extension time, it can be guaranteed that these vehicles pass the actual stop line after the green light time is extended; therefore, a certain section upstream of the actual stop line is called a virtual stop line; virtual stop lines are set for U-turn vehicles, left-turn vehicles and straight-going vehicles, which are called U-turn virtual stop line, left-turn virtual stop line and straight-going virtual stop line respectively;

[0016] For the entrance a, the parameters of the virtual stop line include: the distance D between the left boundary line of the U-turn opening and the U-turn virtual stop line U,a , the distance D between the actual stop line and the left turn virtual stop line L,a , the distance D between the actual stop line and the straight virtual stop line T,a , D U,a , D L,a and D T,a The unit of is m;

[0017] S14, Green light interval time: The green light interval time between adjacent phases includes the yellow light time t Y and all red time t R , t Y and t R The unit of is s;

[0018] S15, minimum green light time and maximum green light time: for the entrance lane a, preset the minimum green light time g for the left turn phase Min,L,a and maximum green time g Max,L,a , preset the minimum green light time g for the straight phase Min,T,a and maximum green time g Max,T,a , g Min,L,a , g Max,L,a , gMin,T,a and g Max,T,a The unit of is s;

[0019] S16, minimum saturation: To ensure the utilization rate of green light time, set the minimum saturation x of forced termination for the left turn phase and the straight phase of the entrance lane a respectively. L,a and x T,a ; If the saturation corresponding to the number of vehicles that can be released during the green light time of the current phase is not less than the minimum saturation, continue to extend the green light time; otherwise, switch to the next phase.

[0020] As a preferred embodiment of the present invention, in the above S2, for the entrance lane a with a U-turn opening and a left-turn short lane, during the left-turn phase green light, the departure process of left-turn vehicles and U-turn vehicles in the short lane area is not affected by the straight-going queue vehicles; during the straight-going phase green light, the departure process of straight-going vehicles in the short lane area is not affected by the left-turn queue vehicles and U-turn queue vehicles; that is, during the green light of each phase, the traffic that has entered the short lane area can pass normally;

[0021] Therefore, the green light time of each phase should meet the vehicle traffic demand in the short lane area; thus, the traffic flow characteristics during the left turn phase green light and the traffic flow characteristics during the straight phase green light are determined as follows:

[0022] S21. Traffic flow characteristics during the left turn phase green light: In the signal phase scheme, whether the U-turn signal is continuous has different effects on the left turn traffic and the U-turn traffic departure process, and has different requirements for the left turn phase green light time, specifically:

[0023] If the left-turn phase of the current entrance lane is followed by the straight-ahead phase of the left entrance lane, the U-turn vehicle that has entered the short lane area during the green light of the left-turn phase will continue to pass in the next phase; at this time, if there are only U-turn vehicles on the left-turn short lane during the green light of the left-turn phase, in order to improve the utilization rate of the green light time, switch to the next phase in advance;

[0024] If the current left-turn phase of the entrance lane is not followed by the straight-ahead phase of the left entrance lane, the U-turn vehicle that has entered the short lane area during the green light of the current left-turn phase of the entrance lane cannot pass normally in the next phase; at this time, in order to allow the U-turn vehicle to leave the intersection as soon as possible, the green light time of the left-turn phase needs to be extended;

[0025] S22. Traffic flow characteristics during the green light period of the straight phase: During the green light period of the straight phase, the straight-going vehicles in the short lane area of ​​the current entrance lane can leave freely, and their departure process is not affected by the continuity of the U-turn signal; during the green light period of the straight phase, the U-turn vehicles in the right entrance lane can also pass, but they do not occupy the space resources of the current entrance lane; therefore, when calculating the green light time of the straight phase, only the traffic demand of the straight-going vehicles in the current entrance lane needs to be considered.

[0026] As a preferred solution of the present invention, in S3, the phase control logic and the phase termination condition are specifically:

[0027] S31, phase control logic: Under the constraints of the minimum green light time and the maximum green light time, in order to avoid secondary queuing of vehicles, the initial green light time must ensure that all queued vehicles on the lane group in the short lane area are fully released; in order to improve the traffic efficiency of the intersection, the green light extension time after the initial green light time must ensure that more subsequent vehicles arriving in the short lane area are released. The subsequent vehicles arriving in the short lane area are referred to as subsequent vehicles;

[0028] In order to avoid the loss of green light time due to excessive green light extension, the sliding time window method is used to gradually extend the green light time. Specifically, if a certain alternative green light extension time in the current time window makes the number of vehicles that can be released greater than the judgment threshold (corresponding to "the green light extension time needs to ensure the release of more vehicles that arrive in the short lane area later", and the judgment threshold is set according to specific traffic needs), then the alternative green light extension time is used as the green light extension time of the current time window, and the next time window is opened after the green light extension time; otherwise, the green light time is no longer extended in the current time window, and it switches to the next phase; the sliding time window length T is 2~5s, and the alternative green light extension time in each time window takes values ​​in {0,1,2,3,…,T}; according to specific traffic needs, the green light extension time can also be not set;

[0029] To ensure the utilization rate of the green light time, calculate the phase saturation corresponding to all the alternative green light extension times in the current time window, and select the alternative green light extension time corresponding to the phase saturation that is not less than the minimum saturation as the green light extension time of the current time window; otherwise, switch to the next phase;

[0030] S32, phase termination condition: To avoid the loss of green light time due to excessive green light time and the accumulation of too many vehicles in queue in the short lane area, which causes the vehicles to queue up to the upstream section, set the termination condition for each phase;

[0031] When calculating the green light extension time, if any of the situations S321-S324 occurs, terminate the current phase:

[0032] S321, the phase green light time reaches the maximum green light time;

[0033] S322: The initial green light time is not fully utilized (i.e., all vehicles have left before the initial green light time ends);

[0034] S323, the phase saturations corresponding to the alternative green light extension times in the current time window are all less than the minimum saturation;

[0035] S324: In the next phase, queued vehicles have overflowed the short lane area.

[0036] As a preferred embodiment of the present invention, in the S4, when calculating the phase green light time, for the left turn phase, the green light time required for the left turn queue vehicles and the U-turn queue vehicles is first calculated to determine the initial green light time of the left turn phase, and then the green light time required for the subsequent left turn vehicles and U-turn vehicles is calculated to determine the green light extension time of the left turn phase; for the straight phase, the green light time required for the straight queue vehicles is first calculated to determine the initial green light time of the straight phase, and then the green light time required for the subsequent straight vehicles is calculated to determine the green light extension time of the straight phase;

[0037] Define k as the vehicle type number, k∈{1,2,3,…,K}, K is the number of vehicle types; the calculation of phase green light time specifically includes the green light time required for queuing vehicles, the green light time required for subsequent vehicles, the initial green light time and green light extension time of the left turn phase, and the initial green light time and green light extension time of the straight phase.

[0038] As a preferred solution of the present invention, the method for calculating the green light time required for the queuing vehicles is:

[0039] When the minimum green light time ends, if the queued vehicle has passed the corresponding virtual stop line, it will definitely be able to leave the intersection before the yellow light of the current phase ends. At this time, the minimum green light time is recorded as the green light time required for the queued vehicle; otherwise, the green light time required is equal to the time required from the phase green light on to the vehicle passing the corresponding virtual stop line;

[0040] definition is the number of the kth type of left-turn queued vehicle in the short lane area of ​​entrance a, is the number of the kth type of U-turn queue vehicle in the short lane area of ​​entrance a, is the number of the k-th straight-line vehicle in the short lane area of ​​entrance lane a; the number is used to represent the corresponding vehicle. , and The required green light time is expressed as:

[0041] ;

[0042] ;

[0043] ;

[0044] In the formula, for The green light time required to leave the intersection, in seconds; The green light on time for the left turn phase is The time required to pass the virtual stop line for turning left, in seconds; for The green light time required to leave the intersection, in seconds; The green light on time for the left turn phase is The time required to pass the virtual stop line for U-turn, in seconds; for The green light time required to leave the intersection, in seconds; The green light on time for the straight phase is The time required to pass the straight virtual stop line, in seconds;

[0045] definition is the number of left-turn queuing vehicles of the kth type in the short lane area of ​​entrance road a, then ; is the number of vehicles in the kth category of U-turn queue in the short lane area of ​​entrance road a, then ; is the number of through-going vehicles of type k in the short lane area of ​​entrance road a, then .

[0046] As a preferred solution of the present invention, the method for calculating the green light time required for the following vehicle is:

[0047] When the initial green light time ends, if the following vehicle has passed the corresponding virtual stop line, the required green light time is 0; otherwise, the required green light time is equal to the time required for the vehicle to travel from the current position to the corresponding virtual stop line; since the value of T is only 2~5s, it is assumed that the acceleration of the following vehicle remains unchanged within a single time window;

[0048] definition is the number of the kth left-turning vehicle that subsequently arrives at the short lane area of ​​entrance road a, is the number of the kth type of U-turn vehicle that arrives at the short lane area of ​​the entrance road a later. The number of the k-th through vehicle that subsequently arrives at the short lane area of ​​entrance road a is used to represent the corresponding vehicle;

[0049] After the initial green light time of the left turn phase ends, , Green light time required to leave the intersection , Respectively expressed as:

[0050] ;

[0051] ;

[0052] In the formula, for The distance from the actual stop line of the entrance road a, in meters; for Speed, in m / s; for Acceleration, in m / s 2 ; for The distance from the left boundary line of the U-turn opening of the entrance a, in meters; for Speed, in m / s; for Acceleration, in m / s 2 ;

[0053] definition is the number of left-turning vehicles of the kth type that subsequently arrive at the short lane area of ​​entrance road a, then ; is the number of the kth type of U-turn vehicles that subsequently arrive at the short lane area of ​​entrance road a, then ;

[0054] After the initial green light time of the straight phase ends, Green light time required to leave the intersection It is expressed as:

[0055] ;

[0056] In the formula, for The distance from the actual stop line of the entrance road a, in meters; for Speed, in m / s; for Acceleration, in m / s 2 ;

[0057] definition is the number of the kth through vehicles that subsequently arrive at the short lane area of ​​entrance road a, then .

[0058] As a preferred embodiment of the present invention, the calculation method of the initial green light time and the green light extension time of the left turn phase is:

[0059] Initial green light time for left turn phase:

[0060] At the end of the minimum green light time of the left-turn phase, if the left-turn queue vehicles and the U-turn queue vehicles have all passed the corresponding virtual stop line, the initial green light time of this phase is equal to the minimum green light time of this phase; otherwise, the initial green light time of this phase is the time required from the moment the green light of this phase is turned on to the time when all the left-turn queue vehicles and the U-turn queue vehicles have passed the corresponding virtual stop line; but if at the end of the maximum green light time of the left-turn phase, there are still left-turn queue vehicles or U-turn queue vehicles that have not passed the corresponding virtual stop line, then the initial green light time of this phase is equal to the maximum green light time of this phase; therefore, the initial green light time of the left-turn phase of entrance a is It is expressed as:

[0061] ;

[0062] In the formula, and They are the maximum green light time required for left-turn queue vehicles and U-turn queue vehicles at entrance lane a, in seconds, respectively:

[0063] ;

[0064] ;

[0065] In the formula, for The distance from the actual stop line of the entrance road a, in meters; for The distance from the left boundary line of the U-turn opening of the entrance a, in meters;

[0066] Left turn phase green light extension time:

[0067] When calculating the green light extension time for the left turn phase within a sliding time window, if or ,but or Able to pass the corresponding virtual stop line within the current time window; if or , or Unable to pass the corresponding virtual stop line within the current time window, ignored at this time or ;

[0068] If the left turn phase is followed by the straight phase on the left entrance road, after the initial green light time of the left turn phase ends, the U-turn vehicle that can pass the virtual stop line of the U-turn within the current sliding time window can definitely leave the intersection in the next phase; at this time, calculate the green light extension time in the rth sliding time window during the left turn phase of the entrance road a When , only the number of left-turning vehicles that can be released in the current time window needs to be considered. It is expressed as:

[0069] ;

[0070] Where r is the number of the sliding time window, r∈{1,2,3,…,R}; R is the number of sliding time windows; The alternative green light extension time for the left turn phase within the sliding time window, in seconds; It means finding the maximum value of the second element in all subsets of the current set and returning the first element in the corresponding subset, that is, finding the alternative green light extension time corresponding to the maximum phase saturation value in the current time window; The green light extension time for the left turn phase in the rth sliding time window of the entrance lane a The corresponding phase saturation is expressed as:

[0071] ;

[0072] In the formula, is the saturation flow rate of the left-turn lane group of entrance lane a, in pcu / s; The green light extension time in the rth sliding time window during the left turn phase is When , the number of left-turning vehicles that can be released by entrance lane a is expressed as:

[0073] ;

[0074] In the formula, is the conversion factor for the kth category of vehicles;

[0075] If the left-turn phase is not followed by a straight-ahead phase on the left entrance lane, after the initial green light time of the left-turn phase ends, the U-turn vehicles that have entered the short lane area cannot continue to drive in the next phase; at this time, considering the number of left-turn vehicles and U-turn vehicles that can be released within the sliding time window, The calculation formula becomes:

[0076] ;

[0077] in, The green light extension time in the rth sliding time window during the left turn phase of entrance lane a is The number of U-turn vehicles that can be released is expressed as:

[0078] ;

[0079] When the green light time of the left turn phase of entrance lane a is extended R times, Need to meet:

[0080] .

[0081] As a preferred solution of the present invention, the calculation method of the initial green light time and the green light extension time of the straight phase is:

[0082] Initial green light time for straight phase:

[0083] The initial green light time of the straight phase must meet the need to clear the straight queue vehicles under the constraints of the minimum green light time and the maximum green light time; therefore, the initial green light time of the straight phase of the entrance road a is It is expressed as:

[0084] ;

[0085] In the formula, The maximum green light time required for vehicles queuing in the entrance lane a, in seconds, is expressed as:

[0086] ;

[0087] In the formula, for The distance from the actual stop line of the entrance road a, in meters;

[0088] Green light extension time for straight phase:

[0089] When calculating the green light extension time for the straight phase within a sliding time window, if , Can drive through the straight virtual stop line within the current time window; if , Unable to drive through the straight virtual stop line within the current time window, ignore Therefore, the green light extension time in the rth sliding time window during the straight phase of the entrance lane a is It is expressed as:

[0090] ;

[0091] In the formula, The alternative green light extension time in the sliding time window during the straight phase green light, unit: s; The green light extension time for the straight phase in the rth sliding time window of the entrance lane a The corresponding phase saturation is expressed as:

[0092] ;

[0093] In the formula, is the saturation flow rate of the through lane group of entrance lane a, in pcu / s; The green light extension time in the rth sliding time window during the straight phase of the entrance lane a is The number of straight vehicles that can be released at this time is expressed as:

[0094] ;

[0095] When the green light time of the straight phase of entrance lane a is extended R times, the following conditions must be met:

[0096] .

[0097] In each formula, min means taking the minimum value, max means taking the maximum value, and sum means summing, which are all well-known function definitions.

[0098] The algorithm involved in the present invention can be executed by an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. The algorithm is implemented by executing software through the processor.

[0099] The beneficial effects of the present invention are:

[0100] When designing the signal phase scheme for the intersection, the present invention takes into account both avoiding traffic conflicts and improving phase flexibility, and adopts dedicated signal control for the U-turn opening, so that the U-turn phase follows the left-turn phase of the current entrance road or the straight-ahead phase of the left entrance road; when calculating the green light time required for the vehicle, it is based on the traffic flow operation law under the joint influence of the intersection channelization scheme and the signal phase scheme, and fully considers the differentiated influence of the continuity of the U-turn signal on the arrival and departure process of the left-turn queuing vehicles or the U-turn queuing vehicles, so that the calculated green light time required for the vehicle is more accurate.

[0101] When determining the phase green light time, the present invention comprehensively considers the real-time needs of various types of turning vehicles, the spatial layout of the intersection and the signal phase scheme, so that the proposed phase green light time calculation method can more accurately respond to the real-time changes of traffic flow, and can provide a more scientific and reasonable signal timing scheme for urban signal intersections, thereby better serving urban travelers. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] Figure 1 It is a schematic diagram of the process of the present invention;

[0103] Figure 2 is a schematic diagram of a channelization scheme for a four-way intersection according to an embodiment of the present invention;

[0104] Figure 3 is a schematic diagram of a signal phase scheme for a north-south intersection in an embodiment of the present invention; Figure 3 (a) is a schematic diagram of the signal phase scheme of "first turn left from north to south, then go straight from north to south"; Figure 3 (b) is a schematic diagram of the signal phase scheme of "first going straight from north to south, then turning left from north to south"; Figure 3 (c) is a schematic diagram of the signal phase scheme of "first go straight left to the south, then go straight left to the north"; Figure 3(d) is a schematic diagram of the signal phase scheme of "first go straight left to the north, then go straight left to the south";

[0105] Figure 4 is a schematic diagram of the position of a virtual stop line in an embodiment of the present invention;

[0106] Figure 5 It is a schematic diagram of the process of a left-turning vehicle or a U-turning vehicle leaving when a left-turning phase is followed by a straight-going phase on a left entrance road in an embodiment of the present invention;

[0107] Figure 6 It is a schematic diagram of the process of a left-turning vehicle or a U-turning vehicle leaving when the left-turning phase is preceded by the straight-going phase of the left entrance road in an embodiment of the present invention;

[0108] Figure 7 is a schematic diagram of a process of a left-turning vehicle or a U-turning vehicle leaving when the left-turning phase is not adjacent to the straight-going phase of the left entrance lane in an embodiment of the present invention;

[0109] Figure 8 Schematic diagram of the process of a straight-moving vehicle leaving the vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0110] The embodiments of the present invention are further described below in conjunction with the accompanying drawings:

[0111] like Figure 1 As shown, a full-sensing control method for an intersection considering a U-turn opening in a connected vehicle environment includes the following steps:

[0112] S1. For the intersections on the road, determine the intersection design scheme and parameters, which include the intersection channelization scheme, signal phase scheme and virtual stop line position, green light interval between adjacent phases, and the minimum green light time, maximum green light time and minimum saturation of each phase;

[0113] S2. Analyze the traffic flow characteristics, including the traffic flow characteristics during the left turn phase with a green light and the traffic flow characteristics during the straight phase with a green light;

[0114] S3. Based on the traffic flow characteristics analyzed in S2, a full-sensing control process is set, and the full-sensing control process includes phase control logic and phase termination conditions;

[0115] S4. Calculate the phase green light time involved in the full-sensing control process to achieve full-sensing control of the intersection considering U-turn opening.

[0116] In S1, the intersection design scheme and parameters are as follows:

[0117] S11, channelization scheme: Figure 2As shown, taking a four-way intersection as an example, for an entrance road a with a U-turn opening and a left-turn short lane, the stop line is called the actual stop line, and the area between the starting section of the entrance road's left-turn short lane and the actual stop line is called the short lane area. The geometric design parameters of the entrance road include: the number of left-turn lanes M L,a =1, number of straight lanes M T,a =2, number of straight right lanes M TR,a =0, number of right turn lanes M R,a =1, U-turn opening width W U,a , U-turn opening position L a , Turn opening length L U,a , left turn short lane length L B,a , W U,a , L a , L U,a , L B,a The unit of is m;

[0118] S12, signal phase scheme: Based on the signal phase scheme of the double-ring structure, the U-turn opening is controlled by a dedicated signal, and the U-turn phase follows the current left-turn phase of the entrance lane or the straight-ahead phase of the left entrance lane; if the current left-turn phase of the entrance lane and the straight-ahead phase of the left entrance lane are adjacent, the U-turn phase will continuously light up green during the green light interval between the two phases, that is, the U-turn signal is continuous; otherwise, the U-turn signal is discontinuous; for the left-turn phase or the straight-ahead phase, the phase green light time is divided into the initial green light time and the green light extension time;

[0119] like Figure 3 As shown, taking the north-south direction as an example, there are 4 signal phase schemes in this direction, see Figure 3 (a), (b), (c) and (d) in Figure 3 As shown in (a), the signal phase scheme in the north-south direction is between two barriers. The phases after the left barrier (the left-turn phase at the south entrance and the left-turn phase at the north entrance) must be started at the same time, but not necessarily ended at the same time. The phases before the right barrier (the straight-ahead phase at the south entrance and the straight-ahead phase at the north entrance) must end at the same time, but not necessarily ended at the same time. Therefore, each signal phase scheme in the north-south direction has three traffic release sequences, that is, there are 12 traffic release sequences in total in this direction. Similarly, there are also four signal phase schemes and 12 traffic release sequences in the east-west direction.

[0120] As shown in Table 1, there are 16 signal phase schemes and 144 traffic release sequences for this intersection. Among them, WB, NB, EB and SB are the east entrance, south entrance, west entrance and north entrance respectively; signal phase schemes 1 and 6 make all U-turn signals continuous, signal phase schemes 2 and 5 make all U-turn signals discontinuous, and the remaining signal phase schemes make half of the U-turn signals continuous. When the U-turn signals are continuous, LT means that the left turn phase of the current entrance lane is first and the straight phase of the left entrance lane is second, and TL means that the straight phase of the left entrance lane is first and the left turn phase of the current entrance lane is second.

[0121] Table 1 Signal phase scheme for four-way intersection

[0122]

[0123] S13, virtual stop line position: when the yellow light is on, if the vehicles near the actual stop line cannot stop safely in front of the actual stop line, they can use the yellow light time to pass the actual stop line; in order to make full use of the green light extension time, when the vehicles in the short lane area pass a certain section upstream of the actual stop line during the green light extension time, it can be guaranteed that these vehicles pass the actual stop line after the green light time is extended; therefore, a certain section upstream of the actual stop line is called a virtual stop line; virtual stop lines are set for U-turn vehicles, left-turn vehicles and straight-going vehicles, which are called U-turn virtual stop line, left-turn virtual stop line and straight-going virtual stop line respectively;

[0124] like Figure 4 As shown in the figure, for the entrance a, the parameters of the virtual stop line include: the distance D between the left boundary line of the U-turn opening and the U-turn virtual stop line U,a , the distance D between the actual stop line and the left turn virtual stop line L,a , the distance D between the actual stop line and the straight virtual stop line T,a , D U,a , D L,a and D T,a The unit of is m;

[0125] S14, Green light interval time: The green light interval time between adjacent phases includes the yellow light time t Y and all red time t R , t Y and t R The unit of is s;

[0126] Usually, t Y Not less than 3s, in order to make full use of the green light to extend the time, D U,a , D L,a and D T,a The distance a vehicle travels at a speed of 30 km / h for 2 seconds is not greater than the distance the vehicle travels at a speed of 30 km / h for 2 seconds. YTake 3~5s, full red time t R The value depends on the actual situation of the intersection.

[0127] S15, minimum green light time and maximum green light time: for the entrance lane a, preset the minimum green light time g for the left turn phase Min,L,a and maximum green time g Max,L,a , preset the minimum green light time g for the straight phase Min,T,a and maximum green time g Max,T,a , g Min,L,a , g Max,L,a , g Min,T,a and g Max,T,a The unit of is s;

[0128] S16, minimum saturation: To ensure the utilization rate of green light time, set the minimum saturation x of forced termination for the left turn phase and the straight phase of the entrance lane a respectively. L,a and x T,a ; If the saturation corresponding to the number of vehicles that can be released during the green light time of the current phase is not less than the minimum saturation, continue to extend the green light time; otherwise, switch to the next phase.

[0129] In S2, for the entrance lane a with a U-turn opening and a left-turn short lane, in the case of vehicle queues (including various well-known queues, such as straight queues, left-turn queues and U-turn queues), during the left-turn phase green light, the departure process of left-turn vehicles and U-turn vehicles in the short lane area is not affected by the straight-going queue vehicles; during the straight-going phase green light, the departure process of straight-going vehicles in the short lane area is not affected by the left-turn queue vehicles and U-turn queue vehicles; that is, during the green light of each phase, the traffic that has entered the short lane area can pass normally;

[0130] Therefore, the green light time of each phase should meet the vehicle traffic demand in the short lane area; thus, the traffic flow characteristics during the left turn phase green light and the traffic flow characteristics during the straight phase green light are determined as follows:

[0131] S21. Traffic flow characteristics during the left turn phase green light: In the signal phase scheme, whether the U-turn signal is continuous has different effects on the left turn traffic and the U-turn traffic departure process, and has different requirements for the left turn phase green light time, specifically:

[0132] If the left-turn phase of the current entrance lane is followed by the straight-ahead phase of the left entrance lane, the U-turn vehicle that has entered the short lane area during the green light of the left-turn phase will continue to pass in the next phase; at this time, if there are only U-turn vehicles on the left-turn short lane during the green light of the left-turn phase, in order to improve the utilization rate of the green light time, switch to the next phase in advance;

[0133] If the current left-turn phase of the entrance lane is not followed by the straight-ahead phase of the left entrance lane, the U-turn vehicle that has entered the short lane area during the green light of the current left-turn phase of the entrance lane cannot pass normally in the next phase; at this time, in order to allow the U-turn vehicle to leave the intersection as soon as possible, the green light time of the left-turn phase needs to be extended;

[0134] S22. Traffic flow characteristics during the green light period of the straight phase: During the green light period of the straight phase, the straight-going vehicles in the short lane area of ​​the current entrance lane can leave freely, and their departure process is not affected by the continuity of the U-turn signal; during the green light period of the straight phase, the U-turn vehicles in the right entrance lane can also pass, but they do not occupy the space resources of the current entrance lane; therefore, when calculating the green light time of the straight phase, only the traffic demand of the straight-going vehicles in the current entrance lane needs to be considered.

[0135] In S3, the phase control logic and phase termination conditions are as follows:

[0136] S31, phase control logic: Under the constraints of the minimum green light time and the maximum green light time, in order to avoid secondary queuing of vehicles, the initial green light time must ensure that all queued vehicles on the lane group in the short lane area are fully released; in order to improve the traffic efficiency of the intersection, the green light extension time after the initial green light time must ensure that more subsequent vehicles arriving in the short lane area are released. The subsequent vehicles arriving in the short lane area are referred to as subsequent vehicles;

[0137] In order to avoid the loss of green light time due to excessive green light extension, the sliding time window method is used to gradually extend the green light time. Specifically, if a certain alternative green light extension time in the current time window makes the number of vehicles that can be released greater than the judgment threshold, the alternative green light extension time is used as the green light extension time of the current time window, and the next time window is opened after the green light extension time; otherwise, the green light time is no longer extended in the current time window, and it switches to the next phase; the sliding time window length T is 2~5s, and the alternative green light extension time in each time window takes values ​​in {0,1,2,3,…,T};

[0138] To ensure the utilization rate of the green light time, calculate the phase saturation corresponding to all the alternative green light extension times in the current time window, and select the alternative green light extension time corresponding to the phase saturation that is not less than the minimum saturation as the green light extension time of the current time window; otherwise, switch to the next phase;

[0139] S32, phase termination condition: To avoid the loss of green light time due to excessive green light time and the accumulation of too many vehicles in queue in the short lane area, which causes the vehicles to queue up to the upstream section, set the termination condition for each phase;

[0140] When calculating the green light extension time, if any of the situations S321-S324 occurs, terminate the current phase:

[0141] S321, the phase green light time reaches the maximum green light time;

[0142] S322, the initial green light time is not fully utilized;

[0143] S323, the phase saturations corresponding to the alternative green light extension times in the current time window are all less than the minimum saturation;

[0144] S324: In the next phase, queued vehicles have overflowed the short lane area.

[0145] In S4, when calculating the phase green light time, for the left-turn phase, the green light time required for the left-turn queue vehicles and the U-turn queue vehicles is first calculated to determine the initial green light time of the left-turn phase, and then the green light time required for the left-turn vehicles and the U-turn vehicles that arrive subsequently is calculated to determine the green light extension time of the left-turn phase; for the straight phase, the green light time required for the straight-going queue vehicles is first calculated to determine the initial green light time of the straight-going phase, and then the green light time required for the straight-going vehicles that arrive subsequently is calculated to determine the green light extension time of the straight-going phase;

[0146] Define k as the vehicle type number, k∈{1,2,3,…,K}, K is the number of vehicle types; the calculation of phase green light time specifically includes the green light time required for queuing vehicles, the green light time required for subsequent vehicles, the initial green light time and green light extension time of the left turn phase, and the initial green light time and green light extension time of the straight phase.

[0147] The calculation method for the green light time required for vehicles in the queue is:

[0148] When the minimum green light time ends, if the queued vehicle has passed the corresponding virtual stop line, it will definitely be able to leave the intersection before the yellow light of the current phase ends. At this time, the minimum green light time is recorded as the green light time required for the queued vehicle; otherwise, the green light time required is equal to the time required from the phase green light on to the vehicle passing the corresponding virtual stop line;

[0149] definition is the number of the kth type of left-turn queued vehicle in the short lane area of ​​entrance a, is the number of the kth type of U-turn queue vehicle in the short lane area of ​​entrance a, is the number of the k-th straight-line vehicle in the short lane area of ​​entrance lane a; the number is used to represent the corresponding vehicle. , and The required green light time is expressed as:

[0150] ;

[0151] ;

[0152] ;

[0153] In the formula, for The green light time required to leave the intersection, in seconds; The green light on time for the left turn phase is The time required to pass the virtual stop line for turning left, in seconds; for The green light time required to leave the intersection, in seconds; The green light on time for the left turn phase is The time required to pass the virtual stop line for U-turn, in seconds; for The green light time required to leave the intersection, in seconds; The green light on time for the straight phase is The time required to pass the straight virtual stop line, in seconds;

[0154] definition is the number of left-turn queuing vehicles of the kth type in the short lane area of ​​entrance road a, then ; is the number of vehicles in the kth category of U-turn queue in the short lane area of ​​entrance road a, then ; is the number of through-going vehicles of type k in the short lane area of ​​entrance road a, then .

[0155] The calculation method for the green light time required by the following vehicle is:

[0156] When the initial green light time ends, if the following vehicle has passed the corresponding virtual stop line, the required green light time is 0; otherwise, the required green light time is equal to the time required for the vehicle to travel from the current position to the corresponding virtual stop line; since the value of T is only 2~5s, it is assumed that the acceleration of the following vehicle remains unchanged within a single time window;

[0157] definition is the number of the kth left-turning vehicle that subsequently arrives at the short lane area of ​​entrance road a, is the number of the kth type of U-turn vehicle that arrives at the short lane area of ​​the entrance road a later. The number of the k-th through vehicle that subsequently arrives at the short lane area of ​​entrance road a is used to represent the corresponding vehicle;

[0158] After the initial green light time of the left turn phase ends, , Green light time required to leave the intersection , Respectively expressed as:

[0159] ;

[0160] ;

[0161] In the formula, for The distance from the actual stop line of the entrance road a, in meters; for Speed, in m / s; for Acceleration, in m / s 2 ; for The distance from the left boundary line of the U-turn opening of the entrance a, in meters; for Speed, in m / s; for Acceleration, in m / s 2 ;

[0162] definition is the number of left-turning vehicles of the kth type that subsequently arrive at the short lane area of ​​entrance road a, then ; is the number of the kth type of U-turn vehicles that subsequently arrive at the short lane area of ​​entrance road a, then ;

[0163] After the initial green light time of the straight phase ends, Green light time required to leave the intersection It is expressed as:

[0164] ;

[0165] In the formula, for The distance from the actual stop line of the entrance road a, in meters; for Speed, in m / s; for Acceleration, in m / s 2 ;

[0166] definition is the number of the kth through vehicles that subsequently arrive at the short lane area of ​​entrance road a, then .

[0167] The calculation method for the initial green light time and the green light extension time of the left turn phase is:

[0168] Initial green light time for left turn phase:

[0169] At the end of the minimum green light time of the left-turn phase, if the left-turn queue vehicles and the U-turn queue vehicles have all passed the corresponding virtual stop line, the initial green light time of this phase is equal to the minimum green light time of this phase; otherwise, the initial green light time of this phase is the time required from the moment the green light of this phase is turned on to the time when all the left-turn queue vehicles and the U-turn queue vehicles have passed the corresponding virtual stop line; but if at the end of the maximum green light time of the left-turn phase, there are still left-turn queue vehicles or U-turn queue vehicles that have not passed the corresponding virtual stop line, then the initial green light time of this phase is equal to the maximum green light time of this phase; therefore, the initial green light time of the left-turn phase of entrance a is It is expressed as:

[0170] ;

[0171] In the formula, and They are the maximum green light time required for left-turn queue vehicles and U-turn queue vehicles at entrance lane a, in seconds, respectively:

[0172] ;

[0173] ;

[0174] In the formula, for The distance from the actual stop line of the entrance road a, in meters; for The distance from the left boundary line of the U-turn opening of the entrance a, in meters;

[0175] Left turn phase green light extension time:

[0176] When calculating the green light extension time for the left turn phase within a sliding time window, if or ,but or Able to pass the corresponding virtual stop line within the current time window; if or , or Unable to pass the corresponding virtual stop line within the current time window, ignored at this time or ;

[0177] like Figure 5 As shown in the figure (the position in the figure refers to the ordinate of the vehicle position, and the same applies to the other figures), if the left turn phase is followed by the straight phase of the left entrance road, after the initial green light time of the left turn phase ends, the U-turn vehicle that can pass the U-turn virtual stop line within the current sliding time window can definitely leave the intersection in the next phase; at this time, calculate the green light extension time in the rth sliding time window during the green light of the left turn phase of the entrance road a When , only the number of left-turning vehicles that can be released in the current time window needs to be considered. It is expressed as:

[0178] ;

[0179] Where r is the number of the sliding time window, r∈{1,2,3,…,R}; R is the number of sliding time windows; The alternative green light extension time for the left turn phase within the sliding time window, in seconds; It means finding the maximum value of the second element in all subsets of the current set and returning the first element in the corresponding subset, that is, finding the alternative green light extension time corresponding to the maximum phase saturation value in the current time window; The green light extension time for the left turn phase in the rth sliding time window of the entrance lane a The corresponding phase saturation is expressed as:

[0180] ;

[0181] In the formula, is the saturation flow rate of the left-turn lane group of entrance lane a, in pcu / s; The green light extension time in the rth sliding time window during the left turn phase is When , the number of left-turning vehicles that can be released by entrance lane a is expressed as:

[0182] ;

[0183] In the formula, is the conversion factor for the kth category of vehicles;

[0184] like Figure 6 and Figure 7 As shown in the figure, if the left-turn phase is not followed by the straight-ahead phase on the left entrance lane, after the initial green light time of the left-turn phase ends, the U-turn vehicles that have entered the short lane area cannot continue to drive in the next phase; at this time, considering the number of left-turn vehicles and U-turn vehicles that can be released in the sliding time window, The calculation formula becomes:

[0185] ;

[0186] in, The green light extension time in the rth sliding time window during the left turn phase of entrance lane a is The number of U-turn vehicles that can be released is expressed as:

[0187] ;

[0188] When the green light time of the left turn phase of entrance lane a is extended R times, Need to meet:

[0189] .

[0190] The calculation method of the initial green light time and the green light extension time in the straight phase is:

[0191] Initial green light time for straight phase:

[0192] like Figure 8 As shown in the figure, the initial green light time of the straight phase must meet the need to clear the straight queue vehicles under the constraints of the minimum green light time and the maximum green light time; therefore, the initial green light time of the straight phase of the entrance road a is It is expressed as:

[0193] ;

[0194] In the formula, The maximum green light time required for vehicles queuing in the entrance lane a, in seconds, is expressed as:

[0195] ;

[0196] In the formula, for The distance from the actual stop line of the entrance road a, in meters;

[0197] Green light extension time for straight phase:

[0198] When calculating the green light extension time for the straight phase within a sliding time window, if , Can drive through the straight virtual stop line within the current time window; if , Unable to drive through the straight virtual stop line within the current time window, ignore Therefore, the green light extension time in the rth sliding time window during the straight phase of the entrance lane a is It is expressed as:

[0199] ;

[0200] In the formula, The alternative green light extension time in the sliding time window during the straight phase green light, unit: s; The green light extension time for the straight phase in the rth sliding time window of the entrance lane a The corresponding phase saturation is expressed as:

[0201] ;

[0202] In the formula, is the saturation flow rate of the through lane group of entrance lane a, in pcu / s; The green light extension time in the rth sliding time window during the straight phase of the entrance lane a is The number of straight vehicles that can be released at this time is expressed as:

[0203] ;

[0204] When the green light time of the straight phase of entrance lane a is extended R times, the following conditions must be met:

[0205] .

Claims

1. A full-sensing control method for intersections considering U-turn opening in a vehicle networking environment, characterized in that The following steps are involved: S1. For the intersections on the road, determine the intersection design scheme and parameters, which include the intersection channelization scheme, signal phase scheme and virtual stop line position, green light interval between adjacent phases, and the minimum green light time, maximum green light time and minimum saturation of each phase; S2. Analyze the traffic flow characteristics, including the traffic flow characteristics during the left turn phase with a green light and the traffic flow characteristics during the straight phase with a green light; S3. Based on the traffic flow characteristics analyzed in S2, a full-sensing control process is set, and the full-sensing control process includes phase control logic and phase termination conditions; S4, calculating the phase green light time involved in the full-sensing control process, and realizing full-sensing control of the intersection considering U-turn opening; In S1, the intersection design scheme and parameters are specifically as follows: S11. Channelization scheme: For an entrance road a with a U-turn opening and a left-turn short lane, the stop line is called the actual stop line, and the area between the starting section of the entrance road's left-turn short lane and the actual stop line is called the short lane area. The geometric design parameters of the entrance road include: entrance road number a, number of left-turn lanes M L,a 、Number of straight lanes M T,a 、Number of straight right lanes M TR,a , Number of right turn lanes M R,a , U-turn opening width W U,a , U-turn opening position L a , Turn-around opening length L U,a , left turn short lane length L B,a , W U,a , L a , L U,a , L B,a The unit of is m; S12, signal phase scheme: Based on the signal phase scheme of the double-ring structure, the U-turn opening is controlled by a dedicated signal, and the U-turn phase follows the current left-turn phase of the entrance lane or the straight-ahead phase of the left entrance lane; if the current left-turn phase of the entrance lane and the straight-ahead phase of the left entrance lane are adjacent, the U-turn phase will continuously light up green during the green light interval between the two phases, that is, the U-turn signal is continuous; otherwise, the U-turn signal is discontinuous; for the left-turn phase or the straight-ahead phase, the phase green light time is divided into the initial green light time and the green light extension time; S13, virtual stop line position: when the yellow light is on, if the vehicles near the actual stop line cannot stop safely in front of the actual stop line, they can use the yellow light time to pass the actual stop line; in order to make full use of the green light extension time, when the vehicles in the short lane area pass a certain section upstream of the actual stop line during the green light extension time, it can be guaranteed that these vehicles pass the actual stop line after the green light time is extended; therefore, a certain section upstream of the actual stop line is called a virtual stop line; virtual stop lines are set for U-turn vehicles, left-turn vehicles and straight-going vehicles, which are called U-turn virtual stop line, left-turn virtual stop line and straight-going virtual stop line respectively; For the entrance a, the parameters of the virtual stop line include: the distance D between the left boundary line of the U-turn opening and the U-turn virtual stop line U,a , the distance D between the actual stop line and the left turn virtual stop line L,a , the distance D between the actual stop line and the straight virtual stop line T,a , D U,a , D L,a and D T,a The unit of is m; S14, Green light interval time: The green light interval time between adjacent phases includes the yellow light time t Y and all red time t R , t Y and t R The unit of is s; S15, minimum green light time and maximum green light time: for the entrance lane a, preset the minimum green light time g for the left turn phase Min,L,a and maximum green time g Max,L,a , preset the minimum green light time g for the straight phase Min,T,a and maximum green time g Max,T,a , g Min,L,a , g Max,L,a , g Min,T,a and g Max,T,a The unit of is s; S16, minimum saturation: To ensure the utilization rate of green light time, set the minimum saturation x of forced termination for the left turn phase and the straight phase of the entrance lane a respectively. L,a and x T,a ; If the saturation corresponding to the number of vehicles that can be released during the green light time of the current phase is not less than the minimum saturation, continue to extend the green light time; otherwise, switch to the next phase; In the above S2, for the entrance lane a with a U-turn opening and a left-turn short lane, during the left-turn phase green light, the departure process of left-turn vehicles and U-turn vehicles in the short lane area is not affected by the straight-going queue vehicles; during the straight-going phase green light, the departure process of straight-going vehicles in the short lane area is not affected by the left-turn queue vehicles and U-turn queue vehicles; that is, during the green light of each phase, the traffic that has entered the short lane area can pass normally; Therefore, the green light time of each phase should meet the vehicle traffic demand in the short lane area; thus, the traffic flow characteristics during the left turn phase green light and the traffic flow characteristics during the straight phase green light are determined as follows: S21. Traffic flow characteristics during the left turn phase green light: In the signal phase scheme, whether the U-turn signal is continuous has different effects on the left turn traffic and the U-turn traffic departure process, and has different requirements for the left turn phase green light time, specifically: If the left-turn phase of the current entrance lane is followed by the straight-ahead phase of the left entrance lane, the U-turn vehicle that has entered the short lane area during the green light of the left-turn phase will continue to pass in the next phase; at this time, if there are only U-turn vehicles on the left-turn short lane during the green light of the left-turn phase, in order to improve the utilization rate of the green light time, switch to the next phase in advance; If the current left-turn phase of the entrance lane is not followed by the straight-ahead phase of the left entrance lane, the U-turn vehicle that has entered the short lane area during the green light of the current left-turn phase of the entrance lane cannot pass normally in the next phase; at this time, in order to allow the U-turn vehicle to leave the intersection as soon as possible, the green light time of the left-turn phase needs to be extended; S22. Traffic flow characteristics during the green light period of the straight phase: During the green light period of the straight phase, the straight vehicles in the short lane area of ​​the current entrance road can leave freely, and their leaving process is not affected by the continuity of the U-turn signal; during the green light period of the straight phase, the U-turn vehicles in the right entrance road can also pass, but they do not occupy the space resources of the current entrance road; therefore, when calculating the green light time of the straight phase, only the traffic demand of the straight vehicles in the current entrance road needs to be considered; In S3, the phase control logic and phase termination conditions are specifically as follows: S31, phase control logic: Under the constraints of the minimum green light time and the maximum green light time, in order to avoid secondary queuing of vehicles, the initial green light time must ensure that all queued vehicles on the lane group in the short lane area are fully released; in order to improve the traffic efficiency of the intersection, the green light extension time after the initial green light time must ensure that more subsequent vehicles arriving in the short lane area are released. The subsequent vehicles arriving in the short lane area are referred to as subsequent vehicles; In order to avoid the loss of green light time due to excessive green light extension, the sliding time window method is used to gradually extend the green light time. Specifically, if a certain alternative green light extension time in the current time window makes the number of vehicles that can be released greater than the judgment threshold, the alternative green light extension time is used as the green light extension time of the current time window, and the next time window is opened after the green light extension time; otherwise, the green light time is no longer extended in the current time window, and it switches to the next phase; the sliding time window length T is 2~5s, and the alternative green light extension time in each time window takes values ​​in {0,1,2,3,…,T}; To ensure the utilization rate of the green light time, calculate the phase saturation corresponding to all the alternative green light extension times in the current time window, and select the alternative green light extension time corresponding to the phase saturation that is not less than the minimum saturation as the green light extension time of the current time window; otherwise, switch to the next phase; S32, phase termination condition: To avoid the loss of green light time due to excessive green light time and the accumulation of too many vehicles in queue in the short lane area, which causes the vehicles to queue up to the upstream section, set the termination condition for each phase; When calculating the green light extension time, if any of the situations S321-S324 occurs, terminate the current phase: S321, the phase green light time reaches the maximum green light time; S322, the initial green light time is not fully utilized; S323, the phase saturations corresponding to the alternative green light extension times in the current time window are all less than the minimum saturation; S324: In the next phase, queued vehicles have overflowed the short lane area; In the above S4, when calculating the phase green light time, for the left-turn phase, the green light time required for the left-turn queue vehicles and the U-turn queue vehicles is first calculated to determine the initial green light time of the left-turn phase, and then the green light time required for the left-turn vehicles and the U-turn vehicles that arrive subsequently is calculated to determine the green light extension time of the left-turn phase; for the straight phase, the green light time required for the straight-going queue vehicles is first calculated to determine the initial green light time of the straight phase, and then the green light time required for the straight-going vehicles that arrive subsequently is calculated to determine the green light extension time of the straight phase; Define k as the vehicle type number, k∈{1,2,3,…,K}, K is the number of vehicle types; the calculation of phase green light time specifically includes the green light time required for queuing vehicles, the green light time required for subsequent vehicles, the initial green light time and green light extension time of the left turn phase, and the initial green light time and green light extension time of the straight phase; The calculation method of the green light time required for the queuing vehicles is: When the minimum green light time ends, if the queued vehicle has passed the corresponding virtual stop line, it will definitely be able to leave the intersection before the yellow light of the current phase ends. At this time, the minimum green light time is recorded as the green light time required for the queued vehicle; otherwise, the green light time required is equal to the time required from the phase green light on to the vehicle passing the corresponding virtual stop line; definition is the number of the kth type of left-turn queued vehicle in the short lane area of ​​entrance a, is the number of the kth type of U-turn queue vehicle in the short lane area of ​​entrance a, is the number of the k-th straight-line vehicle in the short lane area of ​​entrance a; the number is used to represent the corresponding vehicle. , and The required green light time is expressed as: ； ； ； In the formula, for The green light time required to leave the intersection, in seconds; The green light on time for the left turn phase is The time required to pass the virtual stop line for left turn, in seconds; for The green light time required to leave the intersection, in seconds; The green light on time for the left turn phase is The time required to pass the virtual stop line for U-turn, in seconds; for The green light time required to leave the intersection, in seconds; The green light on time for the straight phase is The time required to pass the straight virtual stop line, in seconds; definition is the number of left-turn queuing vehicles of the kth type in the short lane area of ​​entrance road a, then ; is the number of vehicles in the kth category of U-turn queue in the short lane area of ​​entrance road a, then ; is the number of through-going vehicles of type k in the short lane area of ​​entrance road a, then ; The calculation method of the green light time required for the following vehicles is: When the initial green light time ends, if the following vehicle has passed the corresponding virtual stop line, the required green light time is 0; otherwise, the required green light time is equal to the time required for the vehicle to travel from the current position to the corresponding virtual stop line; since the value of T is only 2~5s, it is assumed that the acceleration of the following vehicle remains unchanged within a single time window; definition is the number of the kth left-turning vehicle that subsequently arrives at the short lane area of ​​entrance road a, is the number of the kth type of U-turn vehicle that arrives at the short lane area of ​​the entrance road a later. The number of the k-th through vehicle that subsequently arrives at the short lane area of ​​entrance road a is used to represent the corresponding vehicle; After the initial green light time of the left turn phase ends, , Green light time required to leave the intersection , Respectively expressed as: ； ； In the formula, for The distance from the actual stop line of the entrance road a, in meters; for Speed, in m / s; for Acceleration, in m / s 2 ; for The distance from the left boundary line of the U-turn opening of the entrance a, in meters; for Speed, in m / s; for Acceleration, in m / s 2 ; definition is the number of left-turning vehicles of the kth type that subsequently arrive at the short lane area of ​​entrance road a, then ; is the number of the kth type of U-turn vehicles that subsequently arrive at the short lane area of ​​entrance road a, then ; After the initial green light time of the straight phase ends, Green light time required to leave the intersection It is expressed as: ； In the formula, for The distance from the actual stop line of the entrance road a, in meters; for Speed, in m / s; for Acceleration, in m / s 2 ; definition is the number of the kth through vehicles that subsequently arrive at the short lane area of ​​entrance road a, then ; The calculation method of the initial green light time and the green light extension time of the left turn phase is: Initial green light time for left turn phase: At the end of the minimum green light time of the left-turn phase, if the left-turn queue vehicles and the U-turn queue vehicles have all passed the corresponding virtual stop line, the initial green light time of this phase is equal to the minimum green light time of this phase; otherwise, the initial green light time of this phase is the time required from the moment the green light of this phase is turned on to the time when all the left-turn queue vehicles and the U-turn queue vehicles have passed the corresponding virtual stop line; but if at the end of the maximum green light time of the left-turn phase, there are still left-turn queue vehicles or U-turn queue vehicles that have not passed the corresponding virtual stop line, then the initial green light time of this phase is equal to the maximum green light time of this phase; therefore, the initial green light time of the left-turn phase of entrance a is It is expressed as: ； In the formula, and They are the maximum green light time required for left-turn queue vehicles and U-turn queue vehicles at entrance lane a, in seconds, respectively: ； ； In the formula, for The distance from the actual stop line of the entrance road a, in meters; for The distance from the left boundary line of the U-turn opening of the entrance a, in meters; Left turn phase green light extension time: When calculating the green light extension time for the left turn phase within a sliding time window, if or ,but or Able to pass the corresponding virtual stop line within the current time window; if or , or Unable to pass the corresponding virtual stop line within the current time window, ignored at this time or ; If the left turn phase is followed by the straight phase on the left entrance road, after the initial green light time of the left turn phase ends, the U-turn vehicle that can pass the virtual stop line of the U-turn within the current sliding time window can definitely leave the intersection in the next phase; at this time, calculate the green light extension time in the rth sliding time window during the left turn phase of the entrance road a When , only the number of left-turning vehicles that can be released in the current time window needs to be considered. It is expressed as: ； Where r is the number of the sliding time window, r∈{1,2,3,…,R}; R is the number of sliding time windows; The alternative green light extension time for the left turn phase within the sliding time window, in seconds; It means finding the maximum value of the second element in all subsets of the current set and returning the first element in the corresponding subset, that is, finding the alternative green light extension time corresponding to the maximum phase saturation value in the current time window; The green light extension time for the left turn phase in the rth sliding time window of the entrance lane a The corresponding phase saturation is expressed as: ； In the formula, is the saturation flow rate of the left-turn lane group of entrance lane a, in pcu / s; The green light extension time in the rth sliding time window during the left turn phase is When , the number of left-turning vehicles that can be released by entrance lane a is expressed as: ； In the formula, is the conversion factor for the kth category of vehicles; If the left-turn phase is not followed by a straight-ahead phase on the left entrance lane, after the initial green light time of the left-turn phase ends, the U-turn vehicles that have entered the short lane area cannot continue to drive in the next phase; at this time, considering the number of left-turn vehicles and U-turn vehicles that can be released within the sliding time window, The calculation formula becomes: ； in, The green light extension time in the rth sliding time window during the left turn phase of entrance lane a is The number of U-turn vehicles that can be released is expressed as: ； When the green light time of the left turn phase of entrance lane a is extended R times, Need to meet: ； The calculation method of the initial green light time and the green light extension time of the straight phase is: Initial green light time for straight phase: The initial green light time of the straight phase must meet the need to clear the straight queue vehicles under the constraints of the minimum green light time and the maximum green light time; therefore, the initial green light time of the straight phase of the entrance road a is It is expressed as: ； In the formula, The maximum green light time required for vehicles queuing in the entrance lane a, in seconds, is expressed as: ； In the formula, for The distance from the actual stop line of the entrance road a, in meters; Green light extension time for straight phase: When calculating the green light extension time for the straight phase within a sliding time window, if , Can drive through the straight virtual stop line within the current time window; if , Unable to drive through the straight virtual stop line within the current time window, ignore Therefore, the green light extension time in the rth sliding time window during the straight phase of the entrance lane a is It is expressed as: ； In the formula, The alternative green light extension time in the sliding time window during the straight phase green light, unit: s; The green light extension time for the straight phase in the rth sliding time window of the entrance lane a The corresponding phase saturation is expressed as: ； In the formula, is the saturation flow rate of the through lane group of entrance lane a, in pcu / s; The green light extension time in the rth sliding time window during the straight phase of the entrance lane a is The number of straight vehicles that can be released at this time is expressed as: ； When the green light time of the straight phase of entrance lane a is extended R times, the following conditions must be met: 。

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