Traffic signal timing optimization method for urban updating area

Abstract

The invention discloses a traffic signal timing optimization method for an urban updating area, belongs to the technical field of traffic optimization, and can solve the problem that the overall operation level of a road network of the urban updating area is poor due to the fact that the efficiency is low when a traditional traffic flow control method is used for processing traffic problems of the urban updating area. The method comprises the following steps: S1, determining the number of current running vehicles and the number of ideal running vehicles in a road network of the urban updating area according to traffic flow information of the urban updating area; s2, according to the traffic flow information, the number of current running vehicles and the number of ideal running vehicles, determining the traffic optimization duration of each boundary intersection road entering the interior from the periphery of the boundary line in the urban updating area; and S3, optimizing the initial traffic duration of each boundary intersection road by using the traffic optimization duration to obtain an optimized target traffic duration. The method is used for timing optimization of traffic signals in an urban updating area.

Description

Technical Field

[0001] The invention relates to a method for optimizing traffic signal timing in an urban renewal area, belonging to the technical field of traffic optimization. Background Art

[0002] With the development of society, urban construction has gradually shifted from the era of incremental development focusing on "quantity" to the era of stock development focusing on "quality". Urban renewal has become the main way for major cities in China to transform and develop, and it is also a strategic choice to promote high-quality urban development. As the urban skeleton continues to stretch, emerging economic circles have gradually emerged, but the old city has become "lonely". The large-scale urban construction in the past has overwhelmed the old city. The infrastructure is backward, public space is missing, and the functional division is unclear. Traffic problems have become a key factor hindering the vitality of the old city. The poor road conditions in the back streets and alleys, traffic congestion and frequent accidents, and parking difficulties have seriously affected the residents' lives and travel satisfaction.

[0003] Traditional traffic management mainly relies on new infrastructure to meet the growing traffic demand. However, in the context of urban renewal, traffic management in old cities is constrained by many factors such as the existing road network, traffic organization, residents' travel mode, and the nature of surrounding land use. Traditional methods will produce many inadaptability and mismatch problems when solving traffic problems in the new era. At present, most of the urban renewal in my country is studied from the perspective of urban planning, lacking analysis of the correlation and impact between urban renewal and traffic operation. As a result, the surrounding traffic facilities of many old blocks cannot meet the new traffic demand after renewal, and the contradiction between supply and demand is becoming increasingly prominent. Due to the limitation of land scale, it is difficult to add new traffic infrastructure. Optimizing regional signal control has become an important means to improve the traffic operation efficiency of urban renewal areas. To sum up, at present, the main problems with traffic flow control methods in urban renewal areas are as follows: 1) Traditional traffic flow control methods are no longer suitable for traffic congestion problems in the context of urban renewal, and the road network efficiency in urban renewal areas is low; 2) After urban renewal, regional traffic supply and demand are unbalanced, congestion and accidents are frequent, and most of the traffic problems in urban renewal areas are studied and solved from the perspective of urban and rural planning, and have not been analyzed from the perspective of traffic planning and management, and the traffic congestion problem has not been fundamentally solved. Summary of the invention

[0004] The present invention provides a method for optimizing traffic signal timing in urban renewal areas, which can solve the problem that traditional traffic flow control methods are inefficient in dealing with traffic problems in urban renewal areas, resulting in poor overall operation level of the road network in urban renewal areas.

[0005] The present invention provides a method for optimizing traffic signal timing in an urban renewal area, the method comprising:

[0006] S1. Determine the current number of running vehicles and the ideal number of running vehicles on the road network of the urban renewal area according to the traffic flow information of the urban renewal area;

[0007] S2. Determine the optimized travel time of each boundary intersection road in the urban renewal area according to the traffic flow information, the current number of running vehicles and the ideal number of running vehicles;

[0008] S3. Utilize the optimized travel time to optimize the initial travel time of each boundary intersection road to obtain an optimized target travel time.

[0009] Optionally, the S1 specifically includes:

[0010] According to the traffic flow information of the urban renewal area, determine the number of vehicles leaving the urban renewal area and the number of vehicles currently running on the road network of the urban renewal area in each survey period during the survey period;

[0011] The ideal number of operating vehicles in the road network of the urban renewal area is determined based on the number of departing vehicles and the current number of operating vehicles.

[0012] Optionally, the traffic flow information of the urban renewal area includes the number of vehicles in the starting period of the urban renewal area road network, and the first number of vehicles entering the urban renewal area from the boundary of the urban renewal area, the second number of vehicles leaving the urban renewal area from the boundary of the urban renewal area, the third number of vehicles entering the urban renewal area from the internal parking area of ​​the urban renewal area, and the fourth number of vehicles entering the internal parking area from the urban renewal area in each survey cycle during the survey period.

[0013] Optionally, the determining, according to the number of departing vehicles and the number of currently operating vehicles, an ideal number of operating vehicles in the road network of the urban renewal area is specifically:

[0014] The average value of the current number of operating vehicles within the survey period corresponding to the top M number of departing vehicles is obtained, and the average value is used as the ideal number of operating vehicles in the road network of the urban renewal area.

[0015] Optionally, the S2 specifically includes:

[0016] Determine the number of vehicles to be controlled on each boundary intersection road in the urban renewal area according to the traffic flow information, the current number of running vehicles and the ideal number of running vehicles;

[0017] According to the traffic flow information and the number of vehicles to be controlled, the optimized travel time of each boundary intersection road in the urban renewal area is determined.

[0018] Optionally, determining the number of vehicles to be controlled on each boundary intersection road in the urban renewal area according to the traffic flow information, the current number of running vehicles and the ideal number of running vehicles specifically includes:

[0019] When the current number of running vehicles is greater than the ideal number of running vehicles, the difference between the current number of running vehicles and the ideal number of running vehicles is used as the total number of controlled vehicles that need to be controlled in the periphery of the urban renewal area;

[0020] Obtain the product of the proportion of the number of vehicles entering the urban renewal area from each boundary intersection road in the first number of vehicles and the total number of controlled vehicles, and use the product as the number of vehicles to be controlled at each boundary intersection road in the urban renewal area.

[0021] Optionally, determining the optimized travel time of each boundary intersection road in the urban renewal area according to the traffic flow information and the number of vehicles to be controlled specifically includes:

[0022] Obtain the maximum number of vehicles entering the urban renewal area from each boundary intersection road in all survey cycles, and use the ratio of the maximum value to the duration of the survey cycle as the incoming vehicle flow of each boundary intersection road;

[0023] The ratio of the number of vehicles to be controlled and the traffic flow entering each boundary intersection road is obtained, and the ratio is used as the optimized travel time of each boundary intersection road in the urban renewal area.

[0024] Optionally, the S3 specifically includes:

[0025] Determine the queuing time limit of each boundary intersection road according to the lane information and queuing information of each boundary intersection road;

[0026] The initial travel time of each boundary intersection road is optimized using the optimized travel time and the queuing time limit to obtain an optimized target travel time.

[0027] Optionally, the lane information of each boundary intersection road includes the number of lanes; the queue information of each boundary intersection road includes the number of vehicles currently queued, the queue limit, and the average length of vehicles;

[0028] Determining the queuing time limit of each boundary intersection road according to the lane information and queuing information of each boundary intersection road specifically includes:

[0029] Obtaining the product of the queue limit length of each boundary intersection road and the number of its lanes, and taking the ratio of the product to the average length of the vehicles as the number of vehicles allowed to queue at each boundary intersection road;

[0030] The difference between the current number of queuing vehicles and the allowed number of queuing vehicles of each boundary intersection road is obtained, and the ratio of the difference to the incoming vehicle flow is used as the queuing time limit of each boundary intersection road.

[0031] Optionally, the initial travel time of each boundary intersection road is optimized by using the optimized travel time and the queuing time limit to obtain an optimized target travel time, specifically:

[0032] When the queuing time limit is greater than 0, the difference between the initial travel time and the optimized travel time of each boundary intersection road is obtained, and the sum of the difference and the queuing time limit is used as the optimized target travel time.

[0033] Optionally, the number of vehicles leaving the urban renewal area in each survey period during the survey period is determined according to the traffic flow information of the urban renewal area, specifically:

[0034] The sum of the second number of vehicles and the fourth number of vehicles in each survey period is obtained, and the sum is used as the number of vehicles leaving the urban renewal area in each survey period.

[0035] Optionally, determining the current number of running vehicles on the road network of the urban renewal area in each survey period during the survey period according to the traffic flow information of the urban renewal area specifically includes:

[0036] Obtaining a sum of the first number of vehicles and the third number of vehicles in each survey period, and using the sum as the number of vehicles entering the urban renewal area in each survey period;

[0037] The sum of the number of vehicles in the starting period and the number of vehicles entering in each survey cycle is obtained, and the difference between the sum and the number of vehicles leaving in the corresponding survey cycle is used as the current number of operating vehicles in the road network of the urban renewal area in each survey cycle.

[0038] Optionally, S3 is specifically:

[0039] The difference between the initial travel time and the optimized travel time of each boundary intersection road is obtained, and the difference is used as the optimized target travel time.

[0040] The beneficial effects that the present invention can produce include:

[0041] The urban renewal area traffic signal timing optimization method provided by the present invention determines the current number of running vehicles and the ideal number of running vehicles through the traffic information of the urban renewal area, and then determines the optimized duration of the green light for each boundary intersection road according to the difference between the two and the traffic information of each boundary intersection road entering the interior from the periphery of the boundary line, and optimizes the initial green light duration of each boundary intersection road, thereby realizing the reasonable allocation of vehicles in the road network and greatly improving the overall operation level of the road network in the urban renewal area. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1A flow chart of a method for optimizing traffic signal timing in an urban renewal area provided by an embodiment of the present invention;

[0043] Figure 2 A schematic diagram of a traffic flow model for an urban renewal area provided by an embodiment of the present invention;

[0044] Figure 3 A schematic diagram of a road network in a survey area provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention is described in detail below in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0046] The embodiment of the present invention provides a method for optimizing traffic signal timing in an urban renewal area. Figure 1 As shown, the method includes:

[0047] S1. Determine the current number of running vehicles and the ideal number of running vehicles on the road network of the urban renewal area based on the traffic flow information of the urban renewal area.

[0048] like Figure 2 As shown in Figure 1, the traffic flow information of the urban renewal area includes the number of vehicles N(t) in the starting period of the urban renewal area road network and the number of first vehicles entering the urban renewal area from the boundary of the urban renewal area in each survey period during the survey period. The number of second vehicles leaving the urban renewal area from the urban renewal area boundary The third number of vehicles entering the urban renewal area from the internal parking area of ​​the urban renewal area and the fourth number of vehicles entering the internal parking area from the urban renewal area

[0049] The embodiment of the present invention does not limit the specific values ​​of the investigation period and the investigation cycle, and those skilled in the art can set them according to actual conditions.

[0050] It is worth noting that when investigating the above information, it is necessary to ensure that the investigations are carried out simultaneously.

[0051] (1) Survey of the number of first vehicles entering the urban renewal area from outside the urban renewal area and the number of second vehicles leaving the urban renewal area from the urban renewal area boundary line

[0052] Arrange several volunteers at each intersection outside the urban renewal area, with two volunteers at each intersection. It is recommended to select the survey period from 16:00 to 19:00 for the survey, and record the number of vehicles every t (1min to 3min is recommended). The survey content includes the specific location, time, direction, vehicle type (large, small), quantity, etc.

[0053] (2) Investigate the number of third-party vehicles entering the urban renewal area from the internal parking area of ​​the urban renewal area and the fourth number of vehicles entering the internal parking area from the urban renewal area

[0054] At each entrance and exit of the internal parking area (including internal residential areas or parking lots) of the urban renewal zone, a volunteer is arranged to count the number of vehicles entering and leaving the parking area. The survey time is synchronized with the vehicle survey entering and leaving the periphery of the road network of the urban renewal zone. The number of vehicles is recorded every t (1min to 3min is recommended). The survey content includes the specific location, time, direction, vehicle type (large, small), quantity, etc.

[0055] (3) Investigate the number of vehicles N(t) at the beginning of the road network in the urban renewal area.

[0056] When counting the number of vehicles in the initial period of the road network in the urban renewal area, the survey time in (1) and (2) is synchronized. It is only necessary to survey the number of vehicles in the road network during a survey period of t. A volunteer is assigned to each starting and ending point of each road section. A volunteer selects a reference vehicle at the starting point of the road section and records the license plate number. The volunteer notifies another volunteer at the end of the road section to start counting the number of vehicles leaving the road section until the reference vehicle leaves the road section. The statistical time and the cumulative number of vehicles on the road section are recorded. The number of vehicles counted on all sections in the road network in the urban renewal area can be accumulated as the number of vehicles in the initial period of the road network. The survey content includes time, location, direction, vehicle type, quantity, etc.

[0057] After investigating the above traffic information, S1 specifically includes:

[0058] (1) Based on the traffic flow information of the urban renewal area, determine the number of vehicles leaving the urban renewal area and the number of vehicles currently operating on the road network of the urban renewal area during each survey period.

[0059] First, the sum of the second number of vehicles and the fourth number of vehicles in each survey period is obtained, and the sum is used as the number of vehicles leaving the urban renewal area in each survey period.

[0060] Specifically, the number of second vehicles leaving the urban renewal area from the urban renewal area boundary within the t+1 period is and the fourth number of vehicles entering the internal parking area from the urban renewal area in the t+1 period By adding them together, we can get the number of vehicles leaving the urban renewal area in period t+1 G(N(t+1)). The specific calculation formula is as follows.

[0061]

[0062] Then, the sum of the first number of vehicles and the third number of vehicles in each survey cycle is obtained, and the sum is used as the number of vehicles entering the urban renewal area in each survey cycle; then, the sum of the number of vehicles in the starting period and the number of entering vehicles in each survey cycle is obtained, and the difference between the sum and the number of vehicles leaving in the corresponding survey cycle is used as the current number of operating vehicles in the road network of the urban renewal area in each survey cycle.

[0063] Specifically, the current number of operating vehicles on the road network in the urban renewal area at time t+1 is calculated according to the following formula.

[0064]

[0065] Among them, N(t+1) is the current number of running vehicles on the road network of the urban renewal area at time t+1; N(t) is the current number of running vehicles on the road network of the urban renewal area at time t, that is, the number of vehicles in the starting period of the road network of the urban renewal area; is the number of vehicles entering the urban renewal area from the boundary of the urban renewal area in the t+1 period, that is, the first number of vehicles; is the number of vehicles that leave the urban renewal area from the boundary of the urban renewal area in the t+1 period, that is, the second number of vehicles; is the number of vehicles that enter the urban renewal area from the internal parking area of ​​the urban renewal area in the t+1 period, that is, the third number of vehicles; It is the number of vehicles entering the internal parking area from the urban renewal area within the t+1 period, that is, the fourth number of vehicles.

[0066] (2) Determine the ideal number of operating vehicles on the road network in the urban renewal area based on the number of vehicles leaving the area and the number of vehicles currently in operation.

[0067] Specifically: obtain the average value of the current number of operating vehicles during the survey period corresponding to the top M number of departing vehicles, and use the average value as the ideal number of operating vehicles in the road network of the urban renewal area.

[0068] Wherein, M is a preset value, which is not limited in the embodiment of the present invention, and can be 5, 8 or 10, etc. by way of example.

[0069] According to the above method, the number of vehicles leaving the urban renewal area road network in real time and the number of vehicles currently operating on the urban renewal area road network are continuously calculated every t moment and recorded in chronological order. The top five largest numbers of vehicles leaving the urban renewal area are selected, and then the five currently operating numbers of vehicles on the urban renewal area road network in the corresponding survey period are taken, and the average value is calculated as the ideal number of vehicles N* operating on the urban renewal area road network.

[0070] S2. Determine the optimized travel time of each boundary intersection road from the outer boundary line to the inner part of the urban renewal area based on the traffic flow information, the current number of running vehicles and the ideal number of running vehicles.

[0071] S2 specifically includes:

[0072] (1) Based on the traffic flow information, the current number of running vehicles, and the ideal number of running vehicles, determine the number of vehicles to be controlled at each boundary intersection in the urban renewal area.

[0073] Specifically: when the current number of operating vehicles is greater than the ideal number of operating vehicles, the difference between the current number of operating vehicles and the ideal number of operating vehicles is used as the total number of controlled vehicles that need to be controlled in the periphery of the urban renewal area.

[0074] Compare the ideal number of running vehicles N* of the urban renewal area road network calculated above with the current number of running vehicles in the urban renewal area road network after each survey cycle to obtain the total number of controlled vehicles ΔN*(t+1) that needs to be controlled outside the urban renewal area. The specific calculation formula is as follows:

[0075]

[0076] Among them, ΔN*(t+1) is the total number of controlled vehicles that need to be controlled in the periphery of the urban renewal area in the t+1 period; N(t+1) is the current number of operating vehicles in the road network of the urban renewal area in the t+1 period; N* is the ideal number of operating vehicles in the road network of the urban renewal area.

[0077] When N(t+1)≤N * When , the traffic flow in the urban renewal area is in a non-saturated state. At this time, the traffic volume on the road network is small, and vehicles can smoothly drive into the interior from the periphery of the urban renewal area without queuing. It is judged that the road network state of the urban renewal area is good and no traffic control is required.

[0078] When N(t+1)>N * When the number of vehicles entering the urban renewal area increases gradually and reaches an oversaturated state, the number of vehicles leaving the urban renewal area decreases as the number of vehicles continues to increase, and congestion occurs. Therefore, it is necessary to control the traffic flow and keep the number of vehicles in the congestion close to the ideal number of vehicles, that is, the saturated state. By controlling the entry of peripheral vehicles, the traffic flow is prevented from entering an oversaturated state, thereby ensuring the operating efficiency of the road network.

[0079] After analyzing and judging the road network status of the urban renewal area, the control components of the roads at each boundary intersection in the urban renewal area are analyzed below.

[0080] Specifically, the product of the proportion of the number of vehicles entering the urban renewal area from each boundary intersection road in the first number of vehicles and the total number of controlled vehicles is obtained, and the product is used as the number of vehicles to be controlled on each boundary intersection road in the urban renewal area.

[0081] This step controls the flow by distributing the total number of controlled vehicles to the peripheral boundary intersection roads, as shown in the following formula:

[0082]

[0083] Among them, ΔN i,in (t+1) is the number of vehicles to be controlled assigned to road i at the boundary intersection of the urban renewal area in period t+1; ΔN*(t+1) is the total number of controlled vehicles that need to be controlled outside the urban renewal area in period t+1; is the number of vehicles entering the urban renewal area from the boundary of the urban renewal area in the t+1 period; It is the number of vehicles entering the urban renewal area from the boundary intersection road i of the urban renewal area in the t+1 period.

[0084] (2) Based on traffic flow information and the number of vehicles to be controlled, determine the optimized travel time for each boundary intersection in the urban renewal area.

[0085] Specifically include:

[0086] First, the maximum number of vehicles entering the urban renewal area from each boundary intersection road in all survey cycles is obtained, and the ratio of the maximum value to the duration of the survey cycle is used as the incoming vehicle flow of each boundary intersection road.

[0087] During the survey period, the maximum number of vehicles entering the urban renewal area road network from the boundary intersection road i is selected. Calculate the incoming vehicle flow q of the road network with the corresponding travel time ΔT i,in (t+1), as shown in the following formula:

[0088]

[0089] Among them, q i,in (t+1) is the traffic volume entering the urban renewal area road network from the boundary intersection road i in the t+1 period; is the number of vehicles entering the urban renewal area from the boundary intersection road i of the urban renewal area within the t+1 period; ΔT is the duration of a survey cycle.

[0090] Then, the ratio of the number of vehicles to be controlled and the incoming traffic flow on each boundary intersection road is obtained, and the ratio is used as the optimized travel time of each boundary intersection road in the urban renewal area.

[0091] Taking into account the difference between the current number of running vehicles and the ideal number of running vehicles in the road network of the urban renewal area and the number of vehicles to be controlled at each boundary intersection, the change in the number of vehicles in the system and the import traffic flow in each cycle are calculated. Taking into account the differences in the size and flow of roads at different boundary intersections, a more reasonable green light reduction time ΔT for each cycle is obtained. i,in (t+1) size, as shown in the following formula:

[0092]

[0093] Where, ΔT i,in (t+1) is the green light reduction time of the entrance road of the boundary intersection road i, that is, the traffic optimization time; ΔN i,in (t+1) is the number of vehicles to be controlled assigned to the intersection road i at the boundary of the urban renewal area at time t+1; q i,in (t+1) is the incoming traffic flow from the boundary intersection road i into the urban renewal area road network within the t+1 period.

[0094] S3. Optimize the initial travel time of each boundary intersection road using the optimized travel time to obtain an optimized target travel time.

[0095] Specifically: obtain the difference between the initial travel time and the optimized travel time of each boundary intersection road, and use the difference as the optimized target travel time.

[0096] The green light operation time (i.e. target travel time) of the boundary intersection road i entering the urban renewal area in the next control cycle is T i,in (t+1) can be calculated by the green light running time T of the previous control cycle i,in (t) minus ΔT i,in (t+1) is obtained, see the following formula for details:

[0097] T i,in (t+1)=T i,in (t)-ΔT i,in (t+1) (7)

[0098] Among them, T i,in (t+1) is the green light operation time of road i at the boundary intersection of period t+1 when entering the urban renewal area, that is, the target travel time; T i,in (t) is the green light operation time of road i at the boundary intersection of period t when entering the urban renewal area, that is, the initial travel time; ΔT i,in (t+1) is the green light reduction time of the entrance road of the boundary intersection road i in the t+1 period, that is, the traffic optimization time.

[0099] On the basis of the above, in order to avoid the optimization method causing the queue length of the entrance road to be too long, resulting in overflow of queued vehicles, affecting the traffic efficiency of other sections outside the control area, and to avoid the reduction of the effective green light time in the entrance road direction resulting in insufficient time for pedestrians to cross the street, the present invention also introduces the concept of queuing time limit.

[0100] S3 specifically includes:

[0101] (1) Determine the queue time limit of each boundary intersection road according to the lane information and queue information of each boundary intersection road. The lane information of each boundary intersection road includes the number of lanes; the queue information of each boundary intersection road includes the number of current queued vehicles, the queue limit length, and the average length of vehicles.

[0102] Specifically: First, obtain the product of the queue limit length and the number of lanes of each boundary intersection road, and use the ratio of the product to the average length of the vehicle as the number of vehicles allowed to queue at each boundary intersection road; then, obtain the difference between the current number of vehicles in the queue and the number of vehicles allowed to queue at each boundary intersection road, and use the ratio of the difference to the incoming traffic volume as the queue time limit for each boundary intersection road. For details, please refer to the following formula:

[0103]

[0104] Among them, T d Indicates the queuing time limit, L i represents the maximum queue length allowed at the boundary intersection road i, that is, the queue limit, R i represents the number of lanes of road i at the boundary intersection, l represents the average length of vehicles, and n i Represents the current number of queued vehicles on road i at the boundary intersection.

[0105] (2) The initial travel time of each boundary intersection road is optimized using the optimized travel time and the queuing time limit to obtain the optimized target travel time.

[0106] Specifically: when the queuing time limit is greater than 0, obtain the difference between the initial travel time of each boundary intersection road and its optimized travel time, and use the sum of the difference and the queuing time limit as the optimized target travel time.

[0107] Please refer to the following formula for details:

[0108] T i,in (t+1)=T i,in (t)-ΔT i,in (t+1)+max(0,T d )(9)

[0109] Another embodiment of the present invention provides a method for optimizing traffic signal timing in an urban renewal area, taking the southern area of ​​Xiaozhai business district in Xi'an as the research area (i.e., the urban renewal area), and the specific area is bounded by Xiaozhai West Road and Xiaozhai East Road in the north, Changming Road in the south, Cuihua Road in the east, and the southern section of Zhuque Avenue in the west. Figure 3 The road network layout in the study area includes 22 intersections and 25 road connections. The method specifically includes the following steps:

[0110] Step 1: Investigate traffic information in the urban renewal area.

[0111] 50 volunteers were recruited to investigate the traffic volume of the road network in the urban renewal area, 26 volunteers were assigned to investigate the flow at the regional boundaries, 14 volunteers to investigate the flow within the road network, and 10 volunteers to investigate the mobile vehicles in the internal parking lot. The survey time was 16:00-19:00, and the survey data was recorded every 1 minute. The vehicle data of the west entrance of the southern section of Xiaozhai West Road-Zhuque Avenue are shown in Table 1.

[0112] Table 1 Vehicle data of the west entrance of Xiaozhai West Road-Zhuque Street South Section

[0113]

[0114] Step 2: Calculate the number of vehicles leaving the urban renewal area.

[0115] Based on the traffic volume leaving the urban renewal area boundary and the number of vehicles entering the inner community or parking lot from the road network counted in step 1, the number of vehicles leaving the inner part of the urban renewal area every 1 minute is calculated by formula (1). For example, the number of vehicles leaving the urban renewal area during the time period from 16:05 to 16:06 is calculated.

[0116]

[0117] Some traffic data leaving the urban renewal area are shown in Table 2.

[0118] Table 2 Traffic data leaving the urban renewal area

[0119] time Number of vehicles leaving time Number of vehicles leaving 16：00～16：01 282 16：07～16：08 239 16：01～16：02 269 16：08～16：09 292 16：02～16：03 220 16：09～16：10 247 16：03～16：04 272 16：10～16：11 264 16：04～16：05 209 16：11～16：12 292 16：05～16：06 264 16：12～16：13 214 16：06～16：07 285 16：13～16：14 238

[0120] Step 3: Calculate the current number of vehicles in operation on the road network in the urban renewal area.

[0121] The traffic flow information from 16:00 to 19:00 obtained in step 1 is calculated according to formula (2) to obtain the current number of vehicles running on the urban renewal area road network from 16:01 to 19:00. For example, the current number of vehicles running on the urban renewal area road network at 16:01 is calculated as follows.

[0122]

[0123] Some data on traffic flow of the road network in the urban renewal area are shown in Table 3.

[0124] Table 3 Traffic flow data of road network in urban renewal area

[0125]

[0126] Step 4: Calculate the ideal number of operating vehicles on the road network in the urban renewal area.

[0127] According to the method of step 2 and step 3, the number of vehicles that continuously leave the urban renewal area and the number of vehicles currently running on the urban renewal area road network during the period of 16:00-19:00 are calculated and recorded in chronological order. The top five largest numbers of vehicles leaving the urban renewal area are selected, which are 323, 336, 327, 324, and 317, respectively. The corresponding survey periods are 16:22-16:23, 16:25-16:26, 16:30-16:31, 18:52-18:53, and 18:56-18:57, respectively. The current number of vehicles running on the road network of the five urban renewal areas in the corresponding survey periods is 16186, 16210, 16214, 16314, and 16209, respectively. The average value is calculated as the ideal number of vehicles running on the road network N*.

[0128]

[0129] Step 5: Calculate the total number of vehicles that need to be controlled outside the urban renewal area.

[0130] According to step 4, the ideal number of vehicles in operation on the road network is calculated as N*=16227, and the difference between the number of vehicles in operation on the road network in a certain survey period in step 3 is used to determine the total number of controlled vehicles that need to be controlled in the periphery of the urban renewal area. For example, the total number of controlled vehicles in the survey period from 17:17 to 17:18 is calculated.

[0131] ΔN * (t+1)=N(t+1)-N * =16499-16227=272

[0132] Therefore, ΔN*(t+1)>0, the traffic flow in the urban renewal area is in an oversaturated state. As the number of vehicles continues to increase, the number of vehicles leaving the urban renewal area gradually decreases, resulting in congestion. Therefore, it is necessary to control the traffic flow and keep the number of vehicles in the congestion close to the ideal number of vehicles, that is, the saturated state.

[0133] Step 6: Calculate the number of vehicles to be controlled on each boundary intersection road.

[0134] This step distributes the total number of controlled vehicles in step 5 to the peripheral boundary intersection roads for control, and the number of vehicles entering the north-south entrance road of boundary intersection road 1 from the periphery of the urban renewal area during the period from 17:17 to 17:18 is used. For example, the number of vehicles to be controlled assigned to the boundary intersection road 1 is ΔN 1,in (t+1) is shown below.

[0135]

[0136] Step 7: Calculate the incoming traffic flow of each boundary intersection road.

[0137] During the survey period from 16:00 to 19:00, the maximum number of vehicles entering the urban renewal area road network at the boundary intersection road 1 was selected. The traffic volume q entering the road network can be calculated with the corresponding travel time ΔT 1,in (t+1).

[0138]

[0139] Step 8: Calculate the optimized travel time (i.e., the reduced green light time) of each boundary intersection road.

[0140] Taking into account the difference between the current number of running vehicles and the ideal number of running vehicles in the road network of the urban renewal area and the number of vehicles to be controlled at each boundary intersection, the change in the number of vehicles in the system and the import traffic flow in each cycle are calculated. Taking into account the differences in the size and flow of roads at different boundary intersections, a more reasonable green light reduction time ΔT for each cycle is obtained. 1,in (t+1) size.

[0141]

[0142] Step 9: Calculate the optimized target travel time.

[0143] The green light operation time (i.e. target travel time) of the boundary intersection road 1 entering the urban renewal area in the next control cycle is T 1,in (t+1) can be calculated by the green light running time T of the previous control cycle 1,in (t) minus ΔT 1,in (t+1), and finally the optimized green light operation time (i.e., target travel time) within each system control cycle is obtained.

[0144] T 1,in (t+1)=T 1,in (t)-ΔT 1,in (t+1)=75-12=63

[0145] Finally, it is calculated that the green light time of the north-south entrance of the boundary intersection road 1 is reduced to 63s. If the number of vehicles currently queuing at the entrance is less than the number of vehicles allowed to queue, that is, max(0,T d )=0, no restriction is imposed, and the road network operation status of the urban renewal area can be controlled within the saturation state; if the number of vehicles currently queuing at the entrance is greater than the number of vehicles allowed to queue, that is, max(0,T d )=T d , then use T d To impose constraints.

[0146] The present invention determines the current number of running vehicles and the ideal number of running vehicles in the road network of the urban renewal area by collecting the traffic information of the road network of the urban renewal area. Then, the status of the road network in the urban renewal area is analyzed and judged, and the gap between the operation status of the urban renewal area in the current period and the optimal operation status is determined according to the current number of running vehicles and the ideal number of running vehicles. After comprehensively considering the vehicle operation status of the urban renewal area, the traffic optimization plan of the road network in the urban renewal area is determined, and the traffic signal control plan of the urban renewal area is optimized by using the traffic optimization plan. This method solves the problem that traditional traffic management methods are not suitable for traffic in the new era, realizes the reasonable allocation of vehicles in the road network, and greatly improves the overall operation level of the road network in the urban renewal area. At the same time, this method takes into account the parking lots or internal community vehicles within the regional road network, which is more in line with the actual road network traffic conditions.

[0147] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for optimizing traffic signal timing in an urban renewal area, characterized in that: The method comprises: S1. Determine the current number of running vehicles and the ideal number of running vehicles on the road network of the urban renewal area according to the traffic flow information of the urban renewal area; S2. Determine the optimized travel time of each boundary intersection road from the outer boundary line of the urban renewal area to the inner boundary line according to the traffic flow information, the current number of running vehicles and the ideal number of running vehicles; S3. Utilize the optimized travel time to optimize the initial travel time of each boundary intersection road to obtain an optimized target travel time.

2. The method according to claim 1, characterized in that The S1 specifically includes: According to the traffic flow information of the urban renewal area, determine the number of vehicles leaving the urban renewal area and the number of vehicles currently running on the road network of the urban renewal area in each survey period during the survey period; The ideal number of operating vehicles in the road network of the urban renewal area is determined based on the number of departing vehicles and the current number of operating vehicles.

3. The method according to claim 2, characterized in that The traffic flow information of the urban renewal area includes the number of vehicles in the starting period of the urban renewal area road network, as well as the first number of vehicles entering the urban renewal area from the boundary of the urban renewal area, the second number of vehicles leaving the urban renewal area from the boundary of the urban renewal area, the third number of vehicles entering the urban renewal area from the internal parking area of ​​the urban renewal area, and the fourth number of vehicles entering the internal parking area from the urban renewal area in each survey cycle during the survey period.

4. The method according to claim 2, characterized in that: The determining of the ideal number of operating vehicles in the road network of the urban renewal area according to the number of vehicles leaving and the number of vehicles currently in operation is specifically: The average value of the current number of operating vehicles within the survey period corresponding to the top M number of departing vehicles is obtained, and the average value is used as the ideal number of operating vehicles in the road network of the urban renewal area.

5. The method according to claim 3, characterized in that: The S2 specifically includes: Determine the number of vehicles to be controlled on each boundary intersection road in the urban renewal area according to the traffic flow information, the current number of running vehicles and the ideal number of running vehicles; According to the traffic flow information and the number of vehicles to be controlled, the optimized travel time of each boundary intersection road in the urban renewal area is determined.

6. The method according to claim 5, characterized in that Determining the number of vehicles to be controlled at each boundary intersection road in the urban renewal area according to the traffic flow information, the current number of running vehicles and the ideal number of running vehicles specifically includes: When the current number of running vehicles is greater than the ideal number of running vehicles, the difference between the current number of running vehicles and the ideal number of running vehicles is used as the total number of controlled vehicles that need to be controlled in the periphery of the urban renewal area; Obtain the product of the proportion of the number of vehicles entering the urban renewal area from each boundary intersection road in the first number of vehicles and the total number of controlled vehicles, and use the product as the number of vehicles to be controlled at each boundary intersection road in the urban renewal area.

7. The method according to claim 5, characterized in that Determining the optimized travel time of each boundary intersection road in the urban renewal area according to the traffic flow information and the number of vehicles to be controlled specifically includes: Obtain the maximum number of vehicles entering the urban renewal area from each boundary intersection road in all survey cycles, and use the ratio of the maximum value to the duration of the survey cycle as the incoming vehicle flow of each boundary intersection road; The ratio of the number of vehicles to be controlled and the traffic flow entering each boundary intersection road is obtained, and the ratio is used as the optimized travel time of each boundary intersection road in the urban renewal area.

8. The method according to claim 1, characterized in that The S3 specifically includes: Determine the queuing time limit of each boundary intersection road according to the lane information and queuing information of each boundary intersection road; The initial travel time of each boundary intersection road is optimized using the optimized travel time and the queuing time limit to obtain an optimized target travel time.

9. The method according to claim 8, characterized in that The lane information of each boundary intersection road includes the number of lanes; the queue information of each boundary intersection road includes the number of current queued vehicles, queue limit length, and average vehicle length; Determining the queuing time limit of each boundary intersection road according to the lane information and queuing information of each boundary intersection road specifically includes: Obtaining the product of the queue limit length of each boundary intersection road and the number of its lanes, and taking the ratio of the product to the average length of the vehicles as the number of vehicles allowed to queue at each boundary intersection road; The difference between the current number of queuing vehicles and the allowed number of queuing vehicles of each boundary intersection road is obtained, and the ratio of the difference to the incoming vehicle flow is used as the queuing time limit of each boundary intersection road.

10. The method according to claim 8, characterized in that The initial travel time of each boundary intersection road is optimized by using the optimized travel time and the queuing time limit to obtain the optimized target travel time, which is specifically: When the queuing time limit is greater than 0, the difference between the initial travel time and the optimized travel time of each boundary intersection road is obtained, and the sum of the difference and the queuing time limit is used as the optimized target travel time.

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