CN112435473B - Expressway traffic flow tracing and ramp regulating method combined with historical data - Google Patents

Abstract

The present invention provides a method for tracing the source of expressway traffic flow and controlling the ramp in combination with historical data, which can precisely control the traffic flow of the expressway automatically and without manual intervention, thereby alleviating the congestion problem of the expressway and obtaining more accurate traffic flow. control effect. In the technical scheme of the present invention, according to the historical data of the traffic flow of the upstream ramp, the traffic flow ratio corresponding to each upstream ramp in the traffic flow of the congestion point of the road section to be adjusted is obtained; when formulating a flow limiting control scheme for the upstream ramp , according to the proportion of traffic flow corresponding to each upstream ramp to calculate the number of vehicles allowed on each upstream ramp, and the duration of green and red lights in the next control cycle of the road section to be adjusted.

Description

A method for traceability and ramp regulation of expressway traffic flow combined with historical data

technical field

The invention relates to the technical field of intelligent traffic control, in particular to a method for tracing the source of expressway traffic flow and ramp regulation combined with historical data.

Background technique

Urban expressway is a large-capacity trunk road in the urban road network that bears the long-distance traffic demand, and its traffic efficiency will affect the traffic operation efficiency of the entire city. In recent years, the demand for expressway traffic in major cities has grown rapidly, and some main line sections are often congested or blocked due to the large inflow of on-ramp traffic. The root cause of traffic congestion on expressways is that the demand exceeds the supply and forms a bottleneck point. Under the condition of a certain traffic capacity, in the prior art, the inflow of vehicles is adjusted by controlling the upstream ramp, thereby preventing the main line traffic flow from being in an oversaturated state. However, due to the limitations of previous detection and communication technologies, when the upstream ramp needs to be controlled when congestion occurs, it is impossible to obtain detailed vehicle OD (Origin Destination) data to estimate the correlation between congestion and the traffic volume of each upstream ramp. , to trace the source of congestion on the bottleneck road section. At present, most of the control of the traffic flow on the upstream ramp can only be based on manual experience to set the weight or adjust the average adjustment rate of the upstream ramp to control the flow of the ramp, and it is impossible to implement precise current limiting control.

SUMMARY OF THE INVENTION

In order to solve the problem in the prior art that the traffic flow of the upstream ramp can only be manually controlled to solve the congestion of the expressway, and the precise control cannot be achieved, the present invention provides a method for tracing the traffic flow of the expressway and controlling the ramp by combining historical data, It can automatically and accurately control the traffic flow of expressways without manual intervention, thereby alleviating the congestion problem of expressways and achieving more accurate traffic control effects.

The technical scheme of the present invention is as follows: a method for tracing the source of expressway traffic flow and ramp regulation combined with historical data, characterized in that it comprises the following steps:

S1: Determine the road section to be adjusted and the congestion point;

It is assumed that the incoming direction of each vehicle in the road section to be adjusted includes: the upstream road section and the upstream ramp of the road section;

Set up monitoring points respectively on all the upstream ramps of the road section to be adjusted, the congestion points of the road section to be adjusted, upstream and downstream of the congestion point of the road section to be adjusted; set up traffic detection at all the monitoring points device;

S2: Setting a statistical time period; collecting vehicle information of vehicles passing through all the monitoring points within the statistical time period; traffic flow;

The vehicle information includes: vehicle identity, passing time;

S3: Calculate the proportion of the traffic flow in the statistical time period according to the different directions of incoming vehicles; obtain the traffic flow proportion corresponding to each of the upstream ramps;

S4: preset a monitoring period, and monitor the real-time traffic state of the road section to be adjusted according to the monitoring period;

Confirm the real-time traffic status of the road section to be adjusted;

If the real-time traffic state of the road section to be adjusted is in a normal traffic state, step S4 is executed cyclically;

Otherwise, go to step S5;

S5: When the road section to be adjusted needs to be flow-controlled, formulate a flow-limiting control scheme:

The formulation of the current limiting control scheme includes the following steps:

a1: Use the traffic detectors upstream and downstream of the congestion point of the road section to be adjusted to monitor the current inflow and outflow traffic flow, and based on the traffic capacity of the road section to be adjusted, calculate the vehicles that should be controlled in this current limiting control scheme number;

a2: Based on the number of vehicles to be controlled and the proportion of traffic flow on the upstream ramp, calculate the number of vehicles allowed to be released on the upstream ramp for each of the upstream ramps;

a3: Calculate the green light and red light durations in the next control cycle of the upstream ramp according to the number of vehicles released on the upstream ramp;

S6: Execute the current limiting control scheme; meanwhile, monitor the traffic state of the road section to be adjusted in real time;

If the real-time traffic state of the road section to be adjusted has returned to the normal traffic state, the upstream ramp is withdrawn from the current limiting control scheme; steps S4 to S6 are executed cyclically;

Otherwise, steps S4 to S6 are executed cyclically.

It is further characterized by:

In step S2, the process of collecting vehicle information of vehicles passing through the monitoring point includes the following steps:

b1: Set the statistical time period as k, and the collection end time as time t;

Then, collected from time tk to time t, the passing vehicle information to be analyzed of the vehicle passing through the to-be-adjusted road section is:

b2: Let all the upstream ramps of the road section to be adjusted be R _i , where: i=1, 2...., n, n is the number of upstream ramps of the road section to be adjusted, which is a positive integer;

The starting and ending time periods for the extraction of the passing data corresponding to the upstream ramp R _i are:

内通过匝道R_i的匝道过车身份信息集合为

Based on the monitoring points on each of the upstream ramps _Ri , extract the

The set of identity information for the on-ramp passing through the ramp _Ri is:

为车辆从所述上流匝道R_i上监测点行驶至所述待调整路段的拥堵点所需最长旅行时间；

车辆从所述上流匝道R_i上监测点行驶至所述待调整路段的拥堵点所需最短旅行时间；in,

is the longest travel time required for the vehicle to travel from the monitoring point on the upstream ramp _Ri to the congestion point of the road section to be adjusted;

The shortest travel time required for the vehicle to travel from the monitoring point on the upstream ramp _Ri to the congestion point of the road section to be adjusted;

和所述最短旅行时间

的计算方法如下：said maximum travel time

and the minimum travel time

is calculated as follows:

Suppose: the distance from the monitoring point on the upstream ramp Ri to the congestion point of the road section to be adjusted is DIST _{i ,} and the speed limit value of the road section to be adjusted is SPD _max ;

为述上流匝道R_i上监测点行驶至所述待调整路段的拥堵点之间的路段上的形式车辆，在t-k时刻至t时刻之间的平均车速；α为修改正系数；in,

is the average vehicle speed between the monitoring point on the upstream ramp _Ri and the congestion point of the to-be-adjusted road section, the average vehicle speed between time tk and time t; α is a modified positive coefficient;

In step S3, the process of calculating the proportion of traffic flow corresponding to each of the upstream ramps R _i includes the following steps:

中的每一个过车身份信息s_j，其中：j为

中身份信息的个数，为正整数；c1: Take out the vehicle information to be analyzed in sequence

Each passing identity information s _j in , where: j is

The number of identity information in , which is a positive integer;

中检索；c2: Set s and _j on each of the ramps to pass through the identity information set

search in;

c3: Set a source traffic count for each of said upstream ramps R _i

中检索到了s_j，则将所述上流匝道R_i对应的所述来源交通量计数

加一；if in

If s _j is retrieved in , then count the source traffic volume corresponding to the upstream ramp R _i

plus one;

中的每一个过车身份信息s_j都被检索完毕，则得到t时刻时每个所述上流匝道R_i对应的所述来源交通量计数

until the passing vehicle information to be analyzed

Each passing identity information s _j has been retrieved, then the source traffic count corresponding to each upstream ramp R _i at time t is obtained.

c4: Set the proportion of traffic flow corresponding to each of the upstream ramps _Ri as

其中：n为所述待调整路段的上流匝道个数，为正整数；

Wherein: n is the number of upstream ramps of the road section to be adjusted, which is a positive integer;

In step a1, the calculation method of the number of vehicles to be controlled F _cut described in this current limiting control scheme is:

Let the monitoring period be C, where C is an integer multiple of k for the statistical time period;

The monitoring period is C, the inflow traffic flow of the road section to be adjusted is F _in , the outgoing traffic flow is F _out , and the traffic capacity of the road section to be adjusted is F _max , wherein the values of F _in , F _out , and F _max are The unit is: passenger car equivalent per hour pcu/h;

Wherein, F _i ^h is the hourly inflow of each of the upstream ramps R _i , and the unit is pcu/h;

In step a2, the calculation method of the number of vehicles P _i ^t allowed to be released on the upstream ramp R _i is:

为每一个所述上流匝道R_i对应的通行交通流占比；C为所述监测周期；Wherein: F _i ^t is the count of the source traffic volume corresponding to each upstream ramp Ri at time t after the statistical time period _k ; F _cut is the number of vehicles to be controlled in this current limiting control scheme ;

is the proportion of traffic flow corresponding to each of the upstream ramps R _i ; C is the monitoring period;

和红灯持续时间

的计算方法为：In step a3, the green light duration in the next control cycle of the upstream ramp R _i

and red light duration

The calculation method is:

Wherein, ht is the headway in the lane saturation flow under the control of the signal on the road section to be adjusted.

The present invention provides a method for tracing the source of expressway traffic flow and ramp regulation combined with historical data. According to the historical data of the traffic flow of the upstream ramp, the traffic flow corresponding to each upstream ramp in the traffic flow of the congestion point of the road section to be adjusted is obtained. Flow ratio; when formulating a current-limiting control plan for an upstream ramp, calculate the number of vehicles allowed on each upstream ramp based on the traffic flow ratio corresponding to each upstream ramp, and the green light and The duration of the red light; the current limiting control scheme obtained in the technical solution of the present invention does not need manual experience adjustment, but is calculated and obtained according to the historical data of the upstream ramp. At the same time, a more targeted flow-limiting control plan is formulated for each upstream ramp based on its historical data to ensure more targeted vehicle adjustment, and more precise control of the congestion problem at the congestion point of the adjusted road section. , and then achieve more accurate traffic control effect.

Description of drawings

1 is a schematic flowchart of a method for tracing the source of expressway traffic flow and ramp regulation combined with historical data;

FIG. 2 is an application scenario and a schematic diagram of detector layout according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of traceability analysis according to an embodiment of the present invention.

Detailed ways

As shown in FIG. 1 , a method for tracing the source of expressway traffic flow and ramp regulation combined with historical data of the present invention includes the following steps.

S1: According to the historical traffic state, determine the road sections to be adjusted and the congestion points of the road sections to be adjusted that need to be monitored and controlled in real time (marked as: congestion bottleneck points in Figure 2 and Figure 3);

It is assumed that the incoming direction of each vehicle on the road section to be adjusted includes: the upstream road section and the upstream ramp of the road section;

Set up monitoring points respectively on all upstream ramps of the road section to be adjusted, the congestion points of the road section to be adjusted, upstream and downstream of the congestion point of the road section to be adjusted; set up traffic detectors on all the monitoring points;

As shown in FIG. 2 , which is one of the application scenarios of the embodiment of the present invention, the congestion point section of the expressway is often congested, and the frequently congested road section is set as the road section to be adjusted, in front of the congestion point of the road section to be adjusted, and upstream The entrance ramps (R1~Rn) are respectively set up with monitoring points, and traffic detectors with vehicle identification function (such as video, RFID) are set up to collect and record information such as vehicle identity and passing time passing through the detection points.

S2: Set a statistical time period; collect vehicle information of vehicles passing through all monitoring points within the statistical time period; and then obtain the traffic flow of each upstream ramp by adjusting the road section within the statistical time period; vehicle information includes: vehicle identity , transit time;

The process of collecting vehicle information of vehicles passing through the monitoring point includes the following steps:

b1: Set the statistical time period as k, and the collection end time as time t; in the specific implementation process, the statistical time period k is set according to the traffic flow of the specific road section. It can truly reflect the traffic state, and can limit the amount of data, without causing too much calculation;

Then, the collected vehicle information to be analyzed of vehicles passing through the road section to be adjusted between time tk and time t is:

b2: Let all the upstream ramps of the road section to be adjusted be R _i , where: i=1,2....,n, i is the number of the upstream ramps, n is the number of upstream ramps of the road section to be adjusted, and is positive integer;

The starting and ending time periods for the extraction of the passing data corresponding to the upstream ramp _Ri are:

内通过匝道R_i的匝道过车身份信息集合为

Based on the monitoring points on each upstream ramp _Ri , extract the

The set of identity information for the on-ramp passing through the ramp _Ri is:

为车辆从上流匝道R_i上监测点行驶至待调整路段的拥堵点所需最长旅行时间；

车辆从上流匝道R_i上监测点行驶至待调整路段的拥堵点所需最短旅行时间；in,

is the longest travel time required for the vehicle to travel from the monitoring point on the upstream ramp _Ri to the congestion point of the road section to be adjusted;

The shortest travel time required for the vehicle to travel from the monitoring point on the upstream ramp _Ri to the congestion point of the road section to be adjusted;

和最短旅行时间

的计算方法，包括以下步骤：longest travel time

and minimum travel time

The calculation method includes the following steps:

Let: the distance from the monitoring point on the upstream ramp Ri to the congestion point of the road section to be adjusted is DIST _{i ,} and the speed limit value of the road section to be adjusted is SPD _max ;

为述上流匝道R_i上监测点行驶至待调整路段的拥堵点之间的路段上的形式车辆，在t-k时刻至t时刻之间的平均车速；α为修改正系数，本实施例中取值3～5。in,

is the average vehicle speed between the monitoring point on the upstream ramp _Ri and the congestion point of the road section to be adjusted, the average vehicle speed between the time tk and the time t; α is a modified positive coefficient, which takes the value in this embodiment 3 to 5.

In the technical scheme of the present invention, the current limiting scheme for each upstream ramp is calculated based on its historical data; it is necessary to carry out traceability analysis on the congested traffic flow at the congestion point; The main line detects the OD path of the point, and collects the latitude and longitude of the start and end points of the OD path; in the specific implementation, as shown in Figure 3, the entry ramps R1 to R3 correspond to the paths OD1 to OD3 respectively, and the starting points of OD1 to _OD3 are respectively monitored on the upstream ramp Ri. The end point and the end point are the congestion points of the road section to be adjusted;

根据起止点的经纬度坐标计算得到每一段OD的距离DIST_i，待调整路段的限速值为SPD_max，即可计算t-k至t时段内，车辆从上流匝道R_i通行至拥堵点所需最短旅行时间

和最长旅行时间

Through the data access interface of the Internet travel service platform (such as AutoNavi map, Baidu map, Didi...) according to the statistical time period k, read the data of all OD paths at each time point t (in the time period from tk to t). average speed

Calculate the distance DIST _i of each OD according to the latitude and longitude coordinates of the starting and ending points. The speed limit value of the road section to be adjusted is SPD _max , and then the shortest travel required for vehicles to pass from the upstream ramp _Ri to the congestion point during the period from tk to t can be calculated. time

and maximum travel time

Assume: In the application scenarios shown in Figure 2 and Figure 3, the distance from R ₁ to the congestion point DIST ₁ =300mDIST ₁ , the distance from R ₂ to the congestion point DIST ₂ =1000m, and the distance from R ₃ to the congestion point DIST ₃ =1800m ;

待调整路段限速值

为例，计算匝道R₁～R₃到拥堵点最快时间可计算t-120s至t时段内，匝道R₁～R₃的通行至拥堵点所需最短旅行时间

The value of k is 120s, that is, the average speed between R ₁ ~ R ₃ and the congestion bottleneck point is obtained through Baidu or AutoNavi's data interface every 120s.

The speed limit value of the road section to be adjusted

For example, to calculate the fastest time from the ramps R ₁ to R ₃ to the congestion point, the shortest travel time from the ramp R ₁ to R ₃ to the congestion point can be calculated during the period from t-120s to t.

为：Then, modify the positive coefficient α to be 3 so that the corresponding longest travel time

for:

Then the starting and ending time period of the passing data extraction corresponding to the upstream ramp R _i is:

The start and end time period of the passing data extraction corresponding to R ₁ :

R ₂ corresponds to the start and end time period of the passing data extraction:

_R3 corresponds to the start and end time period of passing data extraction:

Collected between the time t-120s and the time t, the passing vehicle information to be analyzed of the vehicles passing through the road section to be adjusted is:

内通过匝道R_i的匝道过车身份信息集合为

则有：Based on the monitoring points on each upstream ramp _Ri , extract the

The set of identity information for the on-ramp passing through the ramp _Ri is:

Then there are:

S3: Calculate the proportion of the traffic flow in the statistical time period according to the different directions of the vehicles entering it; obtain the proportion of traffic flow corresponding to each upstream ramp;

The process of calculating the proportion of traffic flow corresponding to each upstream ramp R _i includes the following steps:

中的每一个过车身份信息s_j，其中：j为

中身份信息的个数，为正整数；c1: Take out the vehicle information to be analyzed in turn

Each passing identity information s _j in , where: j is

The number of identity information in , which is a positive integer;

中检索；c2: Set the identity information of s and _j on each ramp respectively

search in;

c3: Set a source traffic count for each upstream ramp R _i

中检索到了s_j，则将上流匝道R_i对应的来源交通量计数F_i ^t加一；if in

If s _j is retrieved in _{, then add one to the source traffic count F i t} ^{corresponding} to the upstream ramp Ri;

中的每一个过车身份信息s_j都被检索完毕，则得到t时刻时每个上流匝道R_i对应的来源交通量计数F_i ^t；Until the vehicle information to be analyzed

Each passing identity information s _j in the retrieval is completed, then the source traffic volume count F _i ^t corresponding to each upstream ramp R _i at time t is obtained;

c4: Set the proportion of traffic flow corresponding to each upstream ramp R _i as

其中：n为待调整路段的上流匝道个数，为正整数。

Among them: n is the number of upstream ramps of the road section to be adjusted, which is a positive integer.

中的每一个过车身份信息s_j，将s_j分别在每一个匝道过车身份信息集合

中检索；如果在

中检索到了s_j，则将上流匝道R_i对应的来源交通量计数F_i ^t加一；则有：In the embodiment of the present invention, the information of passing vehicles to be analyzed is sequentially taken out

for each passing identity information _{s j} in the

retrieved in; if in

If s _j is retrieved in _{, then add one to the source traffic count F i t} ^{corresponding} to the upstream ramp Ri; then there are:

F ₁ ^t = {1, 2, 3, 4, 5}

Calculate the proportion of traffic flow corresponding to each upstream ramp R _i

S4: preset a monitoring period C, and monitor the real-time traffic state of the road section to be adjusted according to the monitoring period C;

Confirm the real-time traffic status of the road section to be adjusted;

If the real-time traffic state of the road section to be adjusted is in a normal traffic state, step S4 is executed cyclically; continuous monitoring ensures that abnormal traffic states can be detected in time;

Otherwise, when the real-time traffic state is in an abnormal state and flow control needs to be performed, step S5 is performed;

In specific implementation, the real-time traffic status of the road section to be adjusted is judged based on the existing technology, such as: occupancy rate, average vehicle speed, queue and other indicators detected by the detector to determine whether the congestion point of the road section to be adjusted on the expressway is approaching or traffic congestion occurs.

S5: When traffic control is required for the road section to be adjusted, formulate a current limiting control plan:

The formulation of the current limiting control scheme includes the following steps:

a1: Use the traffic detectors upstream and downstream of the congestion point of the road section to be adjusted to monitor the current inflow and outflow traffic flow, and based on the traffic capacity of the road section to be adjusted, calculate the number of vehicles that should be controlled in this current limiting control scheme;

The calculation method of the number of vehicles F _cut that should be controlled in this current limiting control scheme is:

Let the monitoring period be C, where C is an integer multiple of k for the statistical time period;

The monitoring period is C, the inflow traffic flow of the road section to be adjusted is F _in , the outbound traffic flow is F _out , and the traffic capacity of the road section to be adjusted is F _max , where the units of F _in , F _out , and F _max are: passenger car equivalent pcu/h per hour;

Among them, F _i ^h is the hourly inflow of each upstream ramp R _i , and the unit is pcu/h;

In this embodiment, it is assumed that F _in = _2000pcu /h, Fout = _1500pcu /h, and Fmax =1500pcu/h, the hourly inflows of the ramps R ₁ to R ₃ are respectively:

but:

a2: Based on the number of vehicles to be controlled and the proportion of traffic flow on the upstream ramp, calculate the number of vehicles allowed on the upstream ramp for each upstream ramp;

The calculation method of the number of vehicles P _i ^t allowed to be released on the upstream ramp for each upstream ramp R _i is:

为经过统计时间段k，t时刻时每个上流匝道R_i对应的来源交通量计数；F_cut为本次限流控制方案中应控制车辆数；

为每一个上流匝道R_i对应的通行交通流占比；C为监测周期；in:

is the source traffic count corresponding to each upstream ramp R _i after the statistical time period k and time t; F _cut is the number of vehicles to be controlled in this current limiting control scheme;

is the proportion of traffic flow corresponding to each upstream ramp R _i ; C is the monitoring period;

In this embodiment, the number of vehicles P _i ^t released on the upstream ramp is calculated as follows:

a3: Calculate the duration of green and red lights in the next control cycle of the upstream ramp according to the number of vehicles released on the upstream ramp;

红灯持续时间

的计算方法为：Green light duration in next control cycle of upstream ramp R _i

red light duration

The calculation method is:

Among them, ht is the headway in the lane saturation flow under the control of the signal on the road section to be adjusted;

Among them, the headway (time headway) refers to the time interval between the head ends of two consecutive vehicles passing through a certain section in a queue of vehicles traveling on the same lane, unit: s/Veh.

和红灯持续时间

的计算如下：In this embodiment, the green light duration in the next control cycle of the upstream ramp R _i

and red light duration

is calculated as follows:

So far, the current limiting control scheme of each upstream ramp _Ri is obtained, including the green and red light durations and the number of vehicles to be released in the next control cycle of the upstream ramp _Ri .

S6: Execute the current limiting control scheme; at the same time monitor the traffic status of the road section to be adjusted in real time;

If the real-time traffic state of the road section to be adjusted has returned to the normal traffic state, the upstream ramp R _i is withdrawn from the current limiting control scheme; steps S4 to S6 are executed cyclically, and the traffic state of the road section to be adjusted continues to be monitored in real time and congestion control is performed;

Otherwise, if the road section to be adjusted is still in an abnormal traffic state, steps S4 to S6 are executed cyclically, and based on the existing congestion control effect, the congestion control plan is further formulated and implemented in a targeted manner; the real-time congestion control plan is ensured All of them are aimed at the existing traffic conditions, and can adjust the traffic conditions in a timely and effective manner.

The technical scheme of the present invention realizes the acquisition of the composition and proportion of the traffic flow of the upstream ramp of the congested traffic flow of the expressway through a method for analyzing the traffic flow of the expressway congestion point combined with the historical traffic state; Depending on the size of the traffic volume, different signal control schemes with different adjustment rates are determined for each ramp, and flow restriction and throttling control are carried out based on the source of the congestion point; this method provides accurate decision-making and management for congestion control of expressway congestion points. Data support is more targeted than the previous mode of carrying out flow limiting control for all ramps equally, and the congestion control of expressway congestion points is more targeted, and better control effects can be achieved.

Claims (3)

1. A method for tracing the source of express way traffic flow and regulating and controlling a ramp by combining historical data is characterized by comprising the following steps:

s1: determining a road section to be adjusted and a congestion point;

setting the coming direction of each vehicle on the road section to be adjusted to comprise: an upstream section and an upstream ramp of the section;

monitoring points are respectively arranged at the upstream and the downstream of all the upstream ramps of the road section to be adjusted, the congestion point of the road section to be adjusted and the congestion point of the road section to be adjusted; setting traffic detectors at all the monitoring points;

s2: setting a statistical time period; collecting vehicle information of vehicles passing through all the monitoring points in the statistical time period; then obtaining the traffic flow passing through the adjusting road section and each upstream ramp in the statistical time period;

the vehicle information includes: vehicle identity, time of passage;

s3: respectively calculating the proportion of the traffic flow in the statistical time period according to the difference of the incoming directions of the traffic; obtaining the traffic flow occupation ratio corresponding to each upstream ramp;

s4: presetting a monitoring period, and monitoring the real-time traffic state of the road section to be adjusted according to the monitoring period;

confirming the real-time traffic state of the road section to be adjusted;

if the real-time traffic state of the road section to be adjusted is in the normal traffic state, circularly executing the step S4;

otherwise, go to step S5;

s5: when the road section to be adjusted needs to carry out flow control, a flow limiting control scheme is formulated:

the current limiting control scheme comprises the following steps:

a 1: monitoring the current inflow and outflow traffic flow by utilizing the traffic detectors at the upstream and the downstream of the congestion point of the road section to be adjusted, and calculating the number of vehicles to be controlled in the current flow limiting control scheme based on the traffic capacity of the road section to be adjusted;

in step a1, the number of vehicles to be controlled F in the current limiting control scheme_cutThe calculation method comprises the following steps:

setting the monitoring period as C, wherein C is an integral multiple of k of the statistical time period;

the monitoring period is within C, and the inflow traffic flow of the road section to be adjusted is F_inThe flow rate of the outgoing vehicle is F_outThe traffic capacity of the road section to be adjusted is F_maxWherein F is_in、F_out、F_maxThe unit of (A) is: passenger car equivalent weight is pcu/h per hour;

wherein, F_i ^hFor each of said up-flow ramps R_iThe hourly inflow of (a), in units of pcu/h;

a 2: calculating the number of vehicles released on an upstream ramp allowed to be released on each upstream ramp based on the number of vehicles to be controlled and the traffic flow occupation ratio of the upstream ramps;

step (ii) ofa2, each of the up-flow ramps R_iNumber of vehicles P released on the upstream ramp allowing release_i ^tThe calculation method comprises the following steps:

wherein: f_i ^tFor each of the upstream ramps R at the time of the statistical time period k and t_iCorresponding source traffic volume counts; f_cutThe number of the vehicles to be controlled in the current limiting control scheme is determined;

for each of said up-flow ramps R_iCorresponding traffic flow ratio; c is the monitoring period;

a 3: according to the number of vehicles released on the upstream ramp, calculating the duration time of green light and red light in the next control period of the upstream ramp;

in step a3, the upstream ramp R_iOf the next control period

And duration of red light

The calculation method comprises the following steps:

htm is the headway time distance in the lane saturated flow under the control of the signal on the road section to be adjusted;

s6: executing the current limit control scheme; simultaneously monitoring the traffic state of the road section to be adjusted in real time;

if the real-time traffic state of the road section to be adjusted is recovered to a normal traffic state, the upstream ramp is withdrawn from the current-limiting control scheme; circularly executing the steps S4 to S6;

otherwise, executing steps S4-S6 in a circulating manner;

in step S3, each of the upstream ramps R is calculated_iThe corresponding process of traffic flow ratio comprises the following steps:

c 1: sequentially extracting information of the vehicles to be analyzed

Each of the vehicle passing part information s_jWherein: j is

The number of the medium identity information is a positive integer;

c 2: will s_jPassing vehicle part information sets on each ramp respectively

Searching;

c 3: for each of said up-flow ramps R_iSetting a source traffic volume count F_i ^t；

If at

In which s is retrieved_jThen the upstream ramp R is connected_iCorresponding source traffic count F_i ^tAdding one;

until the information of the passing vehicle to be analyzed

Each of the vehicle passing part information s_jAfter all the upstream ramps are searched, each upstream ramp R at the time of t is obtained_iCorrespond toThe source traffic count of F_i ^t；

c 4: setting each of the upstream ramps R_iThe corresponding passing traffic flow accounts for

Wherein: n is the number of the upstream ramps of the road section to be adjusted and is a positive integer.

2. The expressway traffic flow tracing and ramp regulating method combining historical data according to claim 1, wherein the expressway traffic flow tracing and ramp regulating method comprises the following steps: in step S2, the process of collecting the vehicle information of the vehicle passing through the monitoring point includes the steps of:

b 1: setting the statistical time period as k and the acquisition ending time as t moment;

then, the information of the vehicle to be analyzed passing through the vehicle of the road section to be adjusted between the time t-k and the time t is collected as follows:

b 2: setting all the upstream ramps of the road section to be adjusted to be R_iWherein: n, n is the number of the upstream ramps of the road section to be adjusted and is a positive integer;

the upstream ramp R_iThe corresponding vehicle passing data extraction starting and stopping time period is

Based on each of the upstream ramps R_iUpper monitoring point, extracted at

Inner passage ramp R_iRamp passing vehicle body part information setAre synthesized into

Wherein,

for vehicles from said up-ramp R_iThe maximum travel time required for the upper monitoring point to travel to the congestion point of the road section to be adjusted;

the vehicle goes from the upstream ramp R_iAnd the shortest travel time is required for the upper monitoring point to travel to the congestion point of the road section to be adjusted.

3. The expressway traffic flow tracing and ramp regulating method combining historical data according to claim 2, wherein the expressway traffic flow tracing and ramp regulating method comprises the following steps of: the maximum travel time

And said minimum travel time

The calculation method of (2) is as follows:

setting: the upstream ramp R_iThe distance from the upper monitoring point to the congestion point of the road section to be adjusted is DIST_iThe speed limit value of the road section to be adjusted is SPD_max；

Wherein,

for the above-mentioned upstream ramp R_iDriving a vehicle in a form on a road section between congestion points of the road section to be adjusted by an upper monitoring point, and averaging the vehicle speed between the time t-k and the time t; alpha is a modified positive coefficient.

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