Secondary queuing early warning method and system based on vehicle passing data

Abstract

The invention discloses a secondary queuing early warning method and system based on vehicle passing data, and the method comprises the steps: obtaining all gate vehicle passing data of a fixed time length, and carrying out the matching to generate a vehicle passing pair data set of an adjacent intersection; screening and eliminating passing vehicle data which is parked and detained between adjacent intersections in the passing vehicle pair data set to obtain a primary screening data set; performing secondary queuing judgment on the data according to passing vehicles in the primary screening data set to obtain an initial secondary queuing set; correcting the vehicle queuing state deviation generated by entering the waiting area in the initial secondary queuing set to obtain a final secondary queuing set; and when the data in the final secondary queuing set meets a preset standard, carrying out secondary queuing alarm. According to the method, the problem of secondary queuing false alarm caused by travel time prolonging due to the fact that the vehicle is parked and detained on the roadside or the gate data is acquired in advance after the vehicle enters the waiting area at the previous intersection is considered, so that the final secondary queuing result is more accurate.

Description

Technical Field

[0001] The present invention relates to the field of intelligent transportation technology, and in particular to a secondary queuing warning method and system based on vehicle passing data. Background Art

[0002] With the rapid development of social economy and the rapid growth of urban scale, congestion at signal-controlled intersections has become a difficult problem for cities. Traditional traffic signal control methods can no longer effectively solve the increasingly serious traffic congestion problem, which puts forward new requirements for urban traffic signal control technology. Traffic signal control systems make adaptive timing adjustments according to changes in traffic flow, which is an effective measure to improve intersection operation efficiency and reduce congestion. Changes in traffic flow can be reflected by the queue length at the intersection, the average speed of traffic at the intersection, or the secondary queue of vehicles at the intersection. Secondary queue refers to the situation where vehicles have to stop and wait twice or more before leaving the intersection. Secondary queue means that vehicles need to pass two or more red lights before leaving the intersection, which reflects the traffic congestion at the intersection. The more congested the situation, the more vehicles there are in the secondary queue. If there are no vehicles in the secondary queue, it means that the traffic condition at the intersection is good. In the prior art, a method for determining whether a vehicle has a secondary queue is to directly determine whether the difference between the actual travel time of the vehicle through the road section and the free-flow travel time is greater than the signal cycle length of the intersection; however, it does not take into account the problem of false alarms of secondary queues caused by the extension of the travel time due to the vehicle being parked and stranded on the roadside or the checkpoint data being obtained in advance after the vehicle enters the waiting area at the previous intersection.

[0003] "A method for calculating queue length based on electronic police data" disclosed in Chinese patent literature has a publication number of CN113380036A and a publication date of 2021.09.10, including step S1: data collection: combining the kinematic laws of traffic waves, obtaining the vehicle's license plate number, vehicle type, and time data for leaving the stop line from the START traffic diagnosis and optimization system; step S2: data preprocessing: cleaning abnormal data, missing data, and duplicate data in the electronic police; step S3: determining the number of times the vehicle stops on the road section based on the distribution of travel time; step S4: constructing a method for calculating the queue length at the intersection based on the number of vehicle stops and the time when the vehicle leaves the stop line at the upstream intersection and the time when the vehicle leaves the stop line at the intersection. The method for calculating the number of road stop times in this technical solution is also obtained by comparing the difference between the vehicle's travel time and the free-flow driving time with the length of the intersection signal cycle, that is, it is still the traditional secondary queue calculation method. It also does not take into account the problem of secondary queue false alarms caused by the extension of the travel time due to vehicles parking on the roadside or obtaining the checkpoint data in advance after entering the waiting area at the previous intersection. Summary of the invention

[0004] The present invention aims to overcome the problem of secondary queue false alarms in the prior art, in which the secondary queue calculation is obtained only by comparing the difference between the vehicle's travel time and the free flow travel time with the length of the intersection signal cycle, without considering the problem of secondary queue false alarms caused by the extension of the travel time due to the vehicle parking at the roadside or the acquisition of the checkpoint data in advance after the vehicle enters the waiting area at the previous intersection.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A secondary queue warning method based on vehicle passing data, comprising: Obtain all the vehicle passing data of the checkpoints with a fixed time length, and match and generate a data set of vehicle pairs at adjacent intersections; The vehicle pair data set is filtered to exclude the vehicle data that stops and stays between adjacent intersections, and a filtered data set is obtained; Perform secondary queuing judgment on the data according to the passing vehicles in the primary screening data set to obtain an initial secondary queuing set; Correct the vehicle queue state deviation caused by entering the waiting area in the initial secondary queue set to obtain the final secondary queue set; When the data in the final secondary queuing set meets the preset standard, a secondary queuing alarm is issued.

[0006] The present invention further improves and modifies the secondary queue judgment method of the prior art, taking into account the problem of lengthened travel time caused by reasons such as vehicles being delayed in the middle of driving on the road section between adjacent intersections and vehicles entering the waiting area at the upstream intersection and having their checkpoint data recorded in advance. The screened data used as the basis for judgment focuses on the part of the travel time length caused by the secondary queue, while excluding the data of the travel time length caused by other reasons, thereby obtaining a more accurate secondary queue judgment result. Due to the difference between vehicle delay and early recording at the checkpoint, it is impossible to eliminate both influencing factors at the same time. Therefore, according to the judgment method of the secondary queue and the source of the vehicle pair data, the vehicle pair data due to vehicle delay is first screened and excluded, so that the vehicles passing the road section basically meet the first-in-first-out and the corresponding error range (some vehicles are overtaken by the following vehicles due to driving speed or lane change, but the overtaking time will not exceed a certain time range), thereby obtaining the initial secondary queue result; on this basis, according to the reason for the early recording time caused by entering the waiting area, the status of the vehicles evaluated as the secondary queue is corrected to obtain the final secondary queue result, and according to the result, choose to alarm or not.

[0007] Preferably, the matching and generating of the vehicle pair datasets at adjacent intersections includes: Based on the data of vehicles passing through the checkpoint, all license plates are traversed and the data of the same license plate are arranged in chronological order; Match the vehicle data of the license plate on the road section between adjacent intersections, including the time of entering the upstream intersection and the time of entering the downstream intersection; Based on the flow direction corresponding to the lane where the vehicle enters the downstream intersection, the matching vehicle pair data for each flow direction is recorded.

[0008] Preferably, obtaining the initial secondary queue set comprises: For each pair of vehicles in the filtered data set, calculate the travel time between adjacent intersections; Calculate the free flow travel time of the road sections between adjacent intersections based on the free flow speed of the road sections; In the first screening data set, the vehicle pairs whose travel time minus the free flow travel time is greater than the intersection signal cycle are determined to be secondary queues, and the initial secondary queue set is obtained.

[0009] Preferably, the filtering and excluding of the passing vehicle data set of the passing vehicle data that are parked and stranded between adjacent intersections comprises: For any two pairs of vehicles entering the downstream intersection with the same flow direction; The filter excludes the vehicle pair data that enters the upstream intersection earlier but enters the downstream intersection later, and the difference between the travel time and the travel time of another vehicle pair data exceeds the time difference threshold.

[0010] Preferably, obtaining the final secondary queue set comprises: The initial secondary queue is concentrated, divided according to the lane where the vehicle enters the downstream intersection, and arranged in the order of the time of entering the downstream intersection; for two adjacent pairs of vehicles in the same lane, if the current pair of vehicles is in the secondary queue and the next pair of vehicles is in the non-secondary queue, and the difference in travel time between the current pair of vehicles and the next pair of vehicles is less than the minimum green light time, the current pair of vehicles will be corrected to the non-secondary queue.

[0011] Preferably, the preset criteria for the secondary queuing alarm include: The number of passing vehicle pairs in the final secondary queue set is greater than the sample quantity threshold, and Finally, the ratio of the number of passing vehicle pairs in the secondary queuing set to the number of passing vehicle pairs in the primary screening data set is greater than a preset ratio threshold.

[0012] Preferably, the matching and generating of the vehicle pair data set at adjacent intersections further comprises: Corresponding to the checkpoint vehicle passing data within a fixed time length, if a license plate only matches the vehicle passing data of one intersection, the fixed time length is rolled back to expand the checkpoint vehicle passing data, and the vehicle passing data of the license plate is re-matched.

[0013] Preferably, the free flow travel time of the road sections between adjacent intersections is calculated according to the road section free flow speed, comprising: collecting the historical vehicle travel speeds of the road sections between adjacent intersections within a fixed time period and arranging them in descending order, taking a pre-set percentage of speed samples and averaging them to obtain the road section free flow speed; The free-flow travel time is obtained by dividing the length of the road section between adjacent intersections by the free-flow speed of the road section.

[0014] A secondary queue warning system based on vehicle passing data, comprising: The vehicle passing data collection module collects the vehicle passing data at the checkpoints at the intersection; The matching and screening module matches and generates a data set of passing vehicles at adjacent intersections, and screens and excludes the passing vehicle data of parked vehicles; The queue evaluation module evaluates the secondary queue status of the passing vehicle data and obtains the initial secondary queue set; The correction module corrects the vehicle queue state deviation caused by the vehicle entering the waiting area for the initial secondary queue evaluation result.

[0015] The secondary queue warning system in the present invention is a system covering a large area of ​​road network. A vehicle passing data collection module is set for each intersection to collect vehicle information entering the intersection and the corresponding time, which can also include the time when the vehicle leaves the intersection. After the paving is completed, the secondary queue warning method of the present invention can be used for any two adjacent intersections to perform secondary queue alarm. After determining the two adjacent intersections, the direction of the road section and the checkpoint passing data of vehicles passing the upstream intersection and the downstream intersection in the same direction are determined according to the upstream and downstream relationships between the intersections. In the matching and screening module, matching is generated and a vehicle pair data set is generated and screened and excluded to obtain a primary screening data set; then, a secondary queue evaluation is performed in the queue evaluation module to obtain an initial secondary queue set, and finally, the vehicle status in the initial secondary queue set is corrected in the correction module to obtain a final secondary queue set, so that the secondary queue of vehicles can be judged more accurately.

[0016] Preferably, the vehicle passing data collection module includes a collection unit arranged at each entrance of each intersection; the collection unit collects the time and lane information of the vehicle entering the intersection through the corresponding entrance; The intersection is an area surrounded by the parking lines of each entrance and their extension lines.

[0017] The present invention has the following beneficial effects: after matching the data of passing vehicle pairs between adjacent intersections, firstly, according to the order of entry and exit and the time difference between the order of entry and exit between any two pairs of passing vehicle data, the passing vehicle data with prolonged travel time due to parking and detention are screened out, and the secondary queue false alarm caused by the parking and detention of vehicles in the road section is eliminated; then, after the secondary queue judgment is performed to obtain the initial secondary queue set, the secondary queue state of the vehicle is corrected according to the travel time difference relationship between adjacent vehicles in the same lane, so as to avoid the secondary queue judgment error caused by the vehicle entering the waiting area of ​​the upstream intersection and the entry time of the intersection being recorded in advance, thereby obtaining a more accurate secondary queue judgment result. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of the secondary queuing warning method in the present invention.

[0019] Figure 2 It is a schematic diagram of adjacent intersections in the present invention.

[0020] Figure 3 It is a schematic diagram of the advance recording time of entering the waiting area in the present invention.

[0021] Figure 4 It is a flow chart of screening the passing data of parked and stranded vehicles in the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0023] In the existing method for judging secondary queues at traffic intersections, the travel time of vehicles on the road section between adjacent intersections is first calculated, and then the free flow speed of the corresponding section is obtained to obtain the corresponding free flow travel time. The delay time is subtracted from the travel time, and the delay time is compared with the intersection signal cycle of the downstream intersection. If the delay time is greater than the intersection signal cycle, it means that the vehicles have a secondary queue. If the delay time is less than or equal to the intersection signal cycle, it means that the vehicles have not a secondary queue.

[0024] For the existing secondary queue judgment method, the free flow travel time of the road section is determined according to the actual road section, and the intersection signal cycle is a setting specific to the corresponding intersection. Both are relatively stable parameters with little change, and are not affected by the change factors of individual vehicles. However, the travel time of the vehicle will change according to the different states of the current vehicle and various external factors, including the secondary queue caused by congestion at the downstream intersection, which will prolong the travel time, and the parking and detention of vehicles on the side of the road to get on and off, which will prolong the travel time, and the acquisition unit of the checkpoint will record the time of the vehicle entering the intersection in advance after the vehicle enters the waiting area and waits for the green light, which will prolong the travel time. In order to accurately judge the situation of the secondary queue, it is necessary to exclude the part of the data that causes the travel time to be prolonged due to other factors, and only retain the passing vehicle data pairs whose travel time is prolonged due to the secondary queue, and then make an accurate judgment on the secondary queue.

[0025] Embodiment 1 Figure 1 As shown, a secondary queue warning method based on vehicle passing data includes: Obtain all the vehicle passing data of the checkpoints with a fixed time length, and match and generate a data set of vehicle pairs at adjacent intersections; The vehicle pair data set is filtered to exclude the vehicle data that stops and stays between adjacent intersections, and a filtered data set is obtained; Perform secondary queuing judgment on the data according to the passing vehicles in the primary screening data set to obtain an initial secondary queuing set; Correct the vehicle queue state deviation caused by entering the waiting area in the initial secondary queue set to obtain the final secondary queue set; When the data in the final secondary queuing set meets the preset standard, a secondary queuing alarm is issued.

[0026] It should be noted that the present invention further improves and modifies the secondary queue judgment method of the prior art, taking into account the problem of lengthened travel time caused by reasons such as vehicles being delayed in the middle of driving on the road section between adjacent intersections and vehicles entering the waiting area at the upstream intersection and having their checkpoint data recorded in advance. The screened data used as the basis for judgment focuses on the part of the travel time length caused by the secondary queue, while excluding the data of the travel time length caused by other reasons, thereby obtaining a more accurate secondary queue judgment result.

[0027] Due to the difference between vehicle delay and early recording at the checkpoint, it is impossible to eliminate both influencing factors at the same time. Therefore, according to the judgment method of the secondary queue and the source of the vehicle pair data, the vehicle pair data due to vehicle delay is first screened and excluded, so that the vehicles passing the road section basically meet the first-in-first-out and the corresponding error range (some vehicles are overtaken by the following vehicles due to driving speed or lane change, but the overtaking time will not exceed a certain time range), thereby obtaining the initial secondary queue result; on this basis, according to the reason for the early recording time caused by entering the waiting area, the status of the vehicles evaluated as the secondary queue is corrected to obtain the final secondary queue result, and according to the result, choose to alarm or not.

[0028] It is worth mentioning that the secondary queuing alarm of the present invention is a secondary queuing alarm method at the flow direction level. In actual traffic conditions, left turns, straight driving and right turns correspond to different lanes. When the right-turn traffic light is ignored, the street light time periods for left turns and straight driving in the same traffic signal cycle are different. There are also situations where left turns are more congested and there are a large number of secondary queues while straight driving is relatively smooth. Therefore, at the same entrance of the same intersection, the secondary queuing situation is judged separately according to different flow directions.

[0029] As a specific embodiment, obtaining all the vehicle passing data of the checkpoints of a fixed time length and matching and generating a vehicle pair data set of adjacent intersections includes: Based on the data of vehicles passing through the checkpoint, all license plates are traversed and the data of the same license plate are arranged in chronological order; Match the vehicle data of the license plate on the road section between adjacent intersections, including the time of entering the upstream intersection and the time of entering the downstream intersection; Based on the flow direction corresponding to the lane where the vehicle enters the downstream intersection, the matching vehicle pair data for each flow direction is recorded.

[0030] It should be noted that the vehicle passing data at the checkpoint includes the vehicle's license plate, the ID number of the entry intersection, the lane number entering the intersection and the flow direction corresponding to the lane, the time of entry into the intersection, and the direction of the driving section; for the same license plate, the order of its passing data is determined according to the chronological order, that is, the intersections passed by the vehicle are arranged in chronological order.

[0031] For the matching of vehicle passing data pairs, first determine the road section that needs to judge the secondary queuing status, so as to determine the specific data of the road section, including the number id of the upstream intersection, the number id of the downstream intersection, the length and direction of the road section; match the data of the road section with the vehicle passing data at the checkpoint, find out the vehicle passing data with the same upstream and downstream intersection id and direction of the road section, and add the license plate of the vehicle passing data, the number id of the upstream intersection, the number id of the downstream intersection, the length and direction of the road section, the lane number entering the intersection and the flow direction corresponding to the lane to the vehicle passing data set.

[0032] The data of passing vehicles is obtained by identifying the license plate of the vehicle. The license plate recognition technology automatically identifies and records the license plate number and license plate color of the vehicle in the road network. The obtained license plate data has the advantages of high data accuracy and large detection sample size. The license plate matching algorithm is used to match the license plate data passing through adjacent intersections, and then the vehicle travel time and the time passing through each intersection are deduced based on the time when the vehicle appeared on the road network last time. With the in-depth study of license plate recognition data, the travel time of the vehicle and the time passing through each intersection can be obtained more accurately. After obtaining the data, the upstream and downstream license plate numbers are compared through the algorithm, and the information of the license plate numbers with the same number is integrated to obtain the travel time, driving direction and other travel data of the vehicle. Since the license plate recognition technology can be implemented using existing technology, it is not described in detail.

[0033] like Figure 2 The figure shows a schematic diagram of adjacent intersections. According to the road section direction indicated by the arrow direction, the left side between adjacent intersections is the upstream intersection and the right side is the downstream intersection. The distance from the entrance stop line of the upstream intersection to the entrance stop line of the downstream intersection is the road section length L, which is used to calculate the free flow travel time of the vehicle and determine the travel time of the vehicle.

[0034] The shadow area surrounded by the stop lines at the four entrances of the upstream intersection and the extension lines of the stop lines is the intersection range detected by the passing vehicle data detection module. When a vehicle passes through the stop lines and enters the intersection range, the detection unit records the entrance and time of the corresponding vehicle entering the intersection, as well as the lane number and flow direction of entering the intersection; similarly, the shadow area surrounded by the stop lines at the four entrances of the downstream intersection and the extension lines of the stop lines is the intersection range detected by the passing vehicle data detection module.

[0035] As a specific embodiment, the data is subjected to secondary queuing judgment according to the passing vehicles in the primary screening data set, and the initial secondary queuing set is obtained, including: For each pair of vehicles in the filtered data set, calculate the travel time between adjacent intersections; Calculate the free flow travel time of the road sections between adjacent intersections based on the free flow speed of the road sections; In the first screening data set, the vehicle pairs whose travel time minus the free flow travel time is greater than the intersection signal cycle are determined to be secondary queues, and the initial secondary queue set is obtained.

[0036] It should be noted that the present invention also uses the comparison of the difference between the travel time and the free flow travel time with the intersection signal cycle when making the secondary queue judgment. When making the initial secondary queue judgment, it is necessary to classify according to the flow direction corresponding to the lane entering the downstream intersection, and make independent secondary queue judgments for each flow direction, and then summarize them to obtain the initial secondary queue set. In the initial secondary queue set, the main categories are first divided based on the flow direction, and then divided based on the lane under the same flow, and then arranged in order according to the time when the vehicles entered the downstream intersection under the same lane.

[0037] Specifically, for each pair of passing vehicles, they are sorted according to the downstream intersection, the entrance direction of the downstream intersection, and the lane number. According to the free flow speed of the current section, the free flow travel time of the section is calculated by dividing the section length L by the free flow speed of the section. For each pair of passing vehicles, when the travel time minus the free flow travel time is greater than the intersection signal cycle, the passing vehicle pair is marked as a secondary queue state, otherwise it is marked as a non-secondary queue state.

[0038] Here, travel time T0 refers to the time required for the vehicle to reach the stop line of the downstream intersection from the stop line of the upstream intersection, that is, the difference between the time when the vehicle enters the downstream intersection and the time when it enters the upstream intersection; by matching the license plates, the specific time when the vehicle enters the upstream and downstream intersections can be obtained, and the time difference between the vehicle entering the upstream intersection and entering the downstream intersection is the vehicle's travel time T0; the calculation of this part of the travel time can be obtained through the passing vehicle data.

[0039] Optionally, calculating the free flow travel time of a road section between adjacent intersections according to the free flow speed of the road section includes: Collect the historical vehicle speeds of sections between adjacent intersections within a fixed time period and arrange them in descending order, take the speed samples of the previous set percentage and average them to obtain the free flow speed of the section; The free-flow travel time is obtained by dividing the length of the road section between adjacent intersections by the free-flow speed of the road section.

[0040] The free-flow speed of a road section refers to the speed at which vehicles travel freely and unimpeded on the road section. The free-flow travel time can be obtained by dividing the length of the road section by the free-flow speed of the road section. Specifically, for the selection of the free-flow speed of a certain road section, the historical vehicle speed data of the road section in the previous week can be selected, and all speeds are arranged in descending order. The speed data in the first ninth are selected to calculate the average value to obtain the free-flow speed of the road section.

[0041] The selection of the free-flow speed of the road section for the day can be judged based on the historical data of the previous week (the length of the time period can be selected as needed, such as one day, three days, one week, etc.), and a rolling update can be performed accordingly. That is, for the calculation of the free-flow speed of the road section on any day, the historical data of the previous week of that day can be selected for calculation, and the free-flow speed can be dynamically updated.

[0042] Optionally, the situation of vehicles that had a shorter travel time through the upstream and downstream stop lines on the previous day, i.e., those that did not queue up twice, can be analyzed to find that these vehicles were traveling on a clear road and that the light happened to be green when they passed the intersection; the average travel time of the top 5% of vehicles with the shortest travel time on the previous day can be used as the free-flow travel time for the section.

[0043] As a specific embodiment, when the data in the final secondary queuing set meets the preset standard, a secondary queuing alarm is performed. The preset standard of the secondary queuing alarm includes: The number of passing vehicle pairs in the final secondary queue set is greater than the sample quantity threshold, and Finally, the ratio of the number of passing vehicle pairs in the secondary queuing set to the number of passing vehicle pairs in the primary screening data set is greater than a preset ratio threshold.

[0044] It should be noted that the secondary queue alarm requires not only that the number of vehicles judged as being in the secondary queue state meets the requirement, but also that the proportion of the number of vehicles judged as being in the secondary queue in the total number of samples also meets the requirement. Because the secondary queue judgment is based on the data of vehicles passing through the checkpoint with a fixed time length as the data source, the fixed time length includes several signal cycle lengths of the intersection. When the traffic volume is large and the average speed of vehicles is high, although a certain number of secondary queues may appear, the actual number of vehicles passing through the intersection is greater, and the traffic status is still relatively good, which cannot be used as a basis for alarm judgment; only when both conditions are met can the secondary queue alarm be more able to reflect the current traffic status of the intersection.

[0045] Specifically, the sample quantity threshold of the final secondary queuing set can be set to m (such as 5 vehicles), and the ratio threshold can be set to n (such as 0.25). That is, when the number of vehicle pairs marked as secondary queuing in the final secondary queuing set is greater than 5, and the ratio of the number of vehicle pairs in the final secondary queuing set to the number of process pairs in the primary screening data set is greater than 0.25, it indicates that a secondary queuing alarm is required.

[0046] Furthermore, the time when the secondary queuing alarm is required can be set in advance. Generally, the night is a traffic trough period with fewer vehicles on the road; the day is a peak period of human activity with more vehicles on the road, which is prone to traffic congestion; therefore, a no-alarm period at night can be set (such as 11 pm to 5 am), during which the secondary queuing alarm system does not work and only records the passing data of vehicles entering each intersection; outside of this period, it is in a working state, and an alarm is issued when it is detected that the final secondary queuing set meets the preset standard, otherwise no alarm is issued.

[0047] In addition to providing a secondary queue warning method based on vehicle passing data, the present invention also provides a secondary queue warning system based on vehicle passing data, including: The vehicle passing data collection module collects the vehicle passing data at the checkpoints at the intersection; The matching and screening module matches and generates a data set of passing vehicles at adjacent intersections, and screens and excludes the passing vehicle data of parked vehicles; The queue evaluation module evaluates the secondary queue status of the passing vehicle data and obtains the initial secondary queue set; The correction module corrects the vehicle queue state deviation caused by the vehicle entering the waiting area for the initial secondary queue evaluation result; the alarm module issues a secondary queue alarm when the final secondary queue set meets the preset standard.

[0048] It should be noted that the secondary queue warning system in the present invention is a system covering a large area of ​​road network. A vehicle passing data collection module is set for each intersection to collect vehicle information entering the intersection and the corresponding time, which may also include the time when the vehicle leaves the intersection. After the paving is completed, the secondary queue warning method of the present invention can be used for any two adjacent intersections to perform secondary queue alarms. After determining the two adjacent intersections, the direction of the section and the checkpoint passing data of vehicles passing the upstream intersection and the downstream intersection in the same direction are determined according to the upstream and downstream relationships between the intersections. In the matching and screening module, a matching and generation of a vehicle pair data set is performed and screened and excluded to obtain a primary screening data set; then, a secondary queue evaluation is performed in the queue evaluation module to obtain an initial secondary queue set; finally, the vehicle status in the initial secondary queue set is corrected in the correction module to obtain a final secondary queue set, which can more accurately determine the secondary queue of vehicles.

[0049] Further, the vehicle passing data collection module includes a collection unit arranged at each entrance of each intersection; The collection unit collects the time and lane information of the vehicle entering the intersection through the corresponding entrance; The intersection is the area enclosed by the parking lines of each entrance and their extension lines.

[0050] like Figure 2The figure shows a schematic diagram of adjacent intersections. According to the road section direction indicated by the arrow direction, the left side between adjacent intersections is the upstream intersection and the right side is the downstream intersection. The distance from the entrance stop line of the upstream intersection to the entrance stop line of the downstream intersection is the road section length L, which is used to calculate the free flow travel time of the vehicle and determine the travel time of the vehicle.

[0051] The shadow area surrounded by the stop lines at the four entrances of the upstream intersection and the extension lines of the stop lines is the intersection range detected by the passing vehicle data detection module. When a vehicle passes through the stop lines and enters the intersection range, the detection unit records the entrance and time of the corresponding vehicle entering the intersection, as well as the lane number and flow direction of entering the intersection; similarly, the shadow area surrounded by the stop lines at the four entrances of the downstream intersection and the extension lines of the stop lines is the intersection range detected by the passing vehicle data detection module.

[0052] Embodiment 2: A secondary queue warning method based on vehicle passing data in this embodiment is basically the same as that in Embodiment 1 in terms of method steps, and the main difference lies in the process of matching and generating a vehicle pair data set of adjacent intersections according to the vehicle passing data at the checkpoint, including: Obtain all vehicle passing data at checkpoints of a fixed time length, and match and generate a dataset of vehicle pairs at adjacent intersections.

[0053] It should be noted that in the process of matching and acquiring the vehicle pair data set, the checkpoint vehicle passing data of a fixed time length is intercepted, and the actual travel time required for the vehicle to complete the corresponding road section is less than the fixed time length. Therefore, except for the vehicles whose fixed time length includes the complete travel time of the vehicle, they can directly match and generate process pair data of adjacent intersections. For vehicles that have entered and left the downstream intersection at the beginning time period of the fixed time length, vehicles that have just entered the upstream intersection at the end time period of the fixed time length, and vehicles for which only the checkpoint vehicle passing data of one intersection is recorded within the fixed time length due to other reasons, there is only process data of one intersection and the matching of the vehicle pair data cannot be completed.

[0054] In these cases, some vehicles are indeed in the secondary queue state, but they are not included in the vehicle pair data set because the matching of the vehicle pair data cannot be completed. This will cause the missed judgment of the secondary queue and affect the accuracy. Based on this problem, this embodiment improves the method of obtaining the checkpoint vehicle data as the data source before matching and obtaining the vehicle pair data set.

[0055] Specifically, for the checkpoint vehicle data within a fixed time length, if a license plate only matches the vehicle data of one intersection, the fixed time length is rolled back to expand the checkpoint vehicle data, and the vehicle data of the license plate is re-matched. The fixed time long queue corresponds to the update time interval of the secondary queue warning.

[0056] In a specific embodiment, if the checkpoint vehicle passing data is obtained every five minutes, there may be a situation where the time when the vehicle enters the upstream intersection is before the five-minute time period, and the time when the vehicle enters the downstream intersection is within the five-minute time period; in this case, only the vehicle passing data at the downstream intersection can be matched, and the complete upstream and downstream intersection vehicle passing data cannot be obtained. If this vehicle is in a secondary queue state on this section of road within these five minutes, it cannot be judged by the vehicle passing data pair, so it is necessary to expand the checkpoint vehicle passing data to find the time when the vehicle enters the upstream intersection, that is, roll back a fixed time length, and add the checkpoint vehicle passing data of the previous five-minute period on the basis of these five minutes to complete the matching of the vehicle passing data.

[0057] If the vehicle data at the checkpoint is rolled back for five minutes, that is, expanded to a time period of ten minutes, and still cannot match the time when the vehicle enters the upstream intersection, then the data will be rolled back and expanded to three fixed time lengths to match the vehicle data. If the time when the vehicle enters the upstream intersection still cannot be matched, the expansion and matching will not be continued, because from this part of the vehicle data, the travel time of the vehicle through the road section is far longer than normal, and there may be a situation of staying in the parking lot near the road section or related branches for a long time. Therefore, only the vehicle data related to the time when the vehicle enters the downstream intersection can be matched within a fixed time length.

[0058] In another specific embodiment, if the vehicle passing data at the checkpoint is obtained every five minutes, there may be a situation where the time when the vehicle enters the upstream intersection is within the five-minute time period, but the time when the vehicle enters the downstream intersection is outside the five-minute time period. At this time, this part of the vehicle passing data that only includes the time of entering the upstream intersection can be ignored, because no matter whether the vehicle is stranded or parked somewhere on the road section for more than a fixed time length, it still needs to enter the downstream intersection in the end, that is, within a certain fixed time length period that is continuously updated and collected subsequently, the vehicle passing data entering the downstream intersection will be matched. At this time, the situation is the same as the previous specific embodiment, that is, the time when the vehicle enters the upstream intersection is before a certain five-minute time period, and the time when the vehicle enters the downstream intersection is within the five-minute time period.

[0059] After completing the expansion of the checkpoint passing vehicle data and matching and generating the passing vehicle pair data set of adjacent intersections, the passing vehicle pair data set is screened and excluded from the passing vehicle data of vehicles parked and stranded between adjacent intersections to obtain a filtered data set; Perform secondary queuing judgment on the data according to the passing vehicles in the primary screening data set to obtain an initial secondary queuing set; Correct the vehicle queue state deviation caused by entering the waiting area in the initial secondary queue set to obtain the final secondary queue set; When the data in the final secondary queuing set meets the preset standard, a secondary queuing alarm is issued.

[0060] As an optional embodiment, in some cases, although vehicles can only be matched to the passing data of vehicles entering the downstream intersection, these vehicles may also have the problem of secondary queuing; for example, a vehicle that drives out from a branch parking lot on a road section between adjacent intersections enters the downstream intersection after driving onto the road section. If the vehicle in front of its lane is also waiting in line at a red light, the vehicle may be in a secondary queue. In order to make the judgment of the secondary queue more accurate, vehicles that are only matched to the passing data of a single intersection and are screened out before matching the passing vehicle data set also need to be added to the consideration of the secondary queue judgment in the appropriate judgment process.

[0061] Specifically, for the vehicle passing data that only has the time of entering the downstream intersection, it is excluded from the vehicle passing data set and combined into an additional data set, which includes the vehicle license plate, the time of entering the downstream intersection, the lane number and the corresponding flow direction. In the correction process of obtaining the final secondary queue set, the vehicle passing data in the final secondary queue set is also arranged in time order according to each lane number. The vehicle passing data in the additional data set is inserted into the final secondary queue set according to the same lane number and in time order for further correction. At this time, there are three situations: (1) If a vehicle in the additional data set (which may be one or several consecutive vehicles) is between two vehicles in the secondary queue state, the vehicle is also marked as being in the secondary queue state.

[0062] (2) If the previous vehicle of the vehicle in the additional data set (which may be one or several consecutive vehicles) is in a non-secondary queue and the next vehicle is in a secondary queue, the difference between the time when the additional data vehicle enters the downstream intersection and the time when the previous vehicle (marked as a non-secondary queue vehicle) enters the downstream intersection is used to make a judgment. If the difference is greater than the minimum green light time, the vehicle is marked as being in a secondary queue.

[0063] (3) If the previous vehicle of the vehicle in the additional data set (which may be one or several consecutive vehicles) is in the secondary queue and the next vehicle is in the non-secondary queue state, the vehicle is marked as the secondary queue state based on the difference between the time when the additional data vehicle enters the downstream intersection and the time when the previous vehicle (marked as the non-secondary queue vehicle) enters the downstream intersection. If the difference is greater than the minimum green light time, the vehicle is marked as the secondary queue state.

[0064] After the correction is completed, a new final secondary queue set is obtained, which can obtain a more complete and accurate secondary queue situation of vehicles.

[0065] Then, the sample quantity threshold of the final secondary queuing set is set to m (such as 5 vehicles), and the ratio threshold is set to n (such as 0.25). That is, when the number of vehicle pairs marked as secondary queuing in the final secondary queuing set is greater than 5, and the ratio of the number of vehicle pairs in the final secondary queuing set to the number of process pairs in the primary screening data set is greater than 0.25, it indicates that a secondary queuing alarm is required.

[0066] Embodiment 3. This embodiment is an improvement on Embodiment 1 or Embodiment 2, and provides an optional method for screening out the data of passing vehicles that are parked and stranded between adjacent intersections in the vehicle pair data set, as well as an optional method for correcting the deviation of the vehicle queue state caused by entering the waiting area in the initial secondary queue set.

[0067] A secondary queue warning method based on vehicle passing data, comprising: Obtain all the vehicle passing data at the checkpoints of a fixed time length, and match them to generate a dataset of vehicle pairs at adjacent intersections.

[0068] Based on the data of vehicles passing through the checkpoint, all license plates are traversed and the data of the same license plate are arranged in chronological order; Match the vehicle data of the license plate on the road section between adjacent intersections, including the time of entering the upstream intersection and the time of entering the downstream intersection; exclude or add the vehicle data that only matches the time of entering the downstream intersection to the additional data set; Based on the flow direction corresponding to the lane where the vehicle enters the downstream intersection, the matching vehicle pair data for each flow direction is recorded.

[0069] The data set of passing vehicles is filtered out to exclude the passing vehicle data that stops and stays between adjacent intersections, and a filtered data set is obtained.

[0070] As a specific embodiment, filtering and excluding the passing vehicle data set of the passing vehicle pair that stops and stays between adjacent intersections includes: For any two pairs of vehicles entering the downstream intersection with the same flow direction; The filter excludes the vehicle pair data that enters the upstream intersection earlier but enters the downstream intersection later, and the difference between the travel time and the travel time of another vehicle pair data exceeds the time difference threshold.

[0071] It should be noted that the problem of prolonged travel time due to short-term parking of vehicles in the section between adjacent intersections can be judged based on the order of vehicles entering the upstream intersection and the order of vehicles entering the downstream intersection, as well as the comparison of travel time differences. Considering that even if a vehicle does not stop or linger in the process of the section, it may be overtaken by the rear vehicle due to the driver's personal driving habits or vehicle lane changes, resulting in the problem that the vehicle enters the upstream intersection first and then enters the downstream intersection later (first in, last out), a time difference threshold can be set, that is, the first in, last out vehicles whose travel time difference exceeds the time difference threshold will be screened out.

[0072] Furthermore, in order to reduce the amount of calculation for the subsequent secondary queue judgment of the primary screening data set, the remaining samples can be cleaned after filtering out the first-in-last-out vehicle data with a travel time difference exceeding the time difference threshold. For the secondary queue, the vehicle must have waited for more than a complete intersection signal cycle after the secondary queue. Therefore, the vehicle pair data set is further cleaned to remove the samples with a travel time greater than the intersection signal cycle, and a further narrowed primary screening data set can be obtained. For the vehicle pair samples with a travel time less than the intersection signal cycle, they must not have encountered a red light or only waited for a red light, and there will be no secondary queue, so they do not need to be considered.

[0073] In this embodiment, the intersection signal cycle selected is to obtain the intersection signal cycle of the downstream intersection. If there is no intersection signal cycle data for the downstream intersection, the default is 120 seconds according to normal circumstances; if the obtained intersection signal cycle time of the downstream intersection is less than 60 seconds, the default is 60 seconds.

[0074] The data is judged for secondary queuing according to the passing vehicles in the primary screening data set to obtain the initial secondary queuing set.

[0075] For each pair of vehicles in the filtered data set, calculate the travel time of the road section between adjacent intersections; calculate the free flow travel time of the road section between adjacent intersections according to the free flow speed of the road section; In the first screening data set, the vehicle pairs whose travel time minus the free flow travel time is greater than the intersection signal cycle are determined to be secondary queues, and the initial secondary queue set is obtained.

[0076] The vehicle queue state deviation caused by entering the waiting area in the initial secondary queue set is corrected to obtain the final secondary queue set.

[0077] As a specific embodiment, obtaining the final secondary queue set includes: The initial secondary queue is concentrated, divided according to the lane where the vehicle enters the downstream intersection, and arranged in the order of the time of entering the downstream intersection; for two adjacent pairs of vehicles in the same lane, if the current pair of vehicles is in the secondary queue and the next pair of vehicles is in the non-secondary queue, and the difference in travel time between the current pair of vehicles and the next pair of vehicles is less than the minimum green light time, the current pair of vehicles will be corrected to the non-secondary queue.

[0078] It should be noted that the process of correcting the initial secondary queue set to obtain the final secondary queue set is mainly to correct the problem that after the vehicle enters the waiting area of ​​the upstream intersection, the collection unit of the upstream intersection records the time when the vehicle enters the upstream intersection in advance, which prolongs the travel time and causes deviations in the secondary queue judgment results.

[0079] like Figure 3 The figure shows a schematic diagram of the time of entering the upstream intersection recorded in advance by the collection unit after the vehicle enters the waiting area. The shaded rectangle in the figure represents the vehicle, and the vehicle beyond the stop line is the vehicle entering the waiting area. Under normal circumstances, vehicles wait for the red light to end and turn green after the stop line. In this case, after the vehicle crosses the stop line and enters the upstream intersection, it will directly drive along the section between adjacent intersections to enter the downstream intersection. Therefore, the time it enters the upstream intersection is the starting time of driving along the section, and the time it enters the downstream intersection is the end time of driving along the section. The difference between the two is the accurate travel time.

[0080] However, in order to improve the traffic efficiency of vehicles, most existing intersections will set up a waiting area in front of the stop line. Vehicles can enter the waiting area and wait for the green light within a certain period of time before the intersection signal light turns green. In this case, since the waiting area belongs to the scope of the intersection, after the vehicle enters the waiting area, it will be directly recorded by the acquisition unit as entering the upstream intersection, but in fact the vehicle is still waiting for the red light to turn green before passing. That is, the time of entering the upstream intersection and the time of entering the downstream intersection are recorded in the vehicle passing data, but the actual travel time is the difference between the time of leaving the waiting area and the time of entering the downstream intersection, which is less than the time difference of entering the upstream and downstream intersections in the vehicle passing data. Therefore, when the time difference of entering the upstream and downstream intersections is used as the travel time to judge the secondary queue, it is easy to judge vehicles in a non-secondary queue state as a secondary queue.

[0081] Therefore, the passing data of two adjacent vehicles in the same lane entering the downstream intersection are compared. On the basis that the state of the rear vehicle is non-secondary queuing, whether the front vehicle needs to make a secondary queuing state correction is determined based on whether the difference in travel time between the front vehicle and the rear vehicle is less than the minimum green light time. The reason is that for the vehicle entering the waiting area at the upstream intersection, the rear vehicle may be parked behind the stop line waiting for the green light and has not entered the upstream intersection. They pass through the upstream intersection in the same green light cycle. The time difference between the two entering the upstream intersection is the time the front vehicle enters the waiting area in advance and the travel time difference between the front and rear vehicles. For vehicles passing through the intersection in the same green light cycle, the time difference between the front vehicle and the rear vehicle corresponds to the minimum green light time. Therefore, the minimum green light time can be used as the travel time difference standard to determine whether a secondary queuing state correction is needed.

[0082] Specifically, the minimum green light time during the secondary queue state correction process is the minimum green light time corresponding to the upstream intersection, and the corresponding minimum green light time can be directly obtained through the road section information, or it is 25 seconds by default. In this embodiment, when the initial secondary queue set is corrected, the vehicle pair with the rear vehicle in the non-secondary queue state and the front vehicle in the secondary queue state is first selected, and then correction is started from the back to the front until all state corrections are completed.

[0083] When the data in the final secondary queuing set meets the preset standard, a secondary queuing alarm is issued.

[0084] As an optional embodiment, in some cases, although the data of passing vehicles that stop and stay between adjacent intersections are screened out and the problem of misjudgment of secondary queues is avoided, these vehicles that stop and stay midway may also have the problem of secondary queues (that is, although the situation where there is no secondary queue but it is misjudged as a secondary queue is avoided; however, the situation where a secondary queue exists but is screened out and not counted in the secondary queue may be missed); that is, a vehicle stops midway on the road section between adjacent intersections, and at the same time, it also has a secondary queue at the downstream intersection; in order to make the judgment of the secondary queue more accurate, for the vehicles excluded in the process of screening out the first screening data set, it is also necessary to add them to the consideration of the secondary queue judgment in the appropriate judgment process.

[0085] Specifically, for the passing vehicle data with intermediate stops, they are excluded from the primary screening data set and separately combined into a secondary additional data set, which includes the vehicle's license plate, time of entering the downstream intersection, lane number and corresponding flow direction. In the correction process of obtaining the final secondary queue set, the passing vehicle data in the final secondary queue set is also arranged in chronological order according to each lane number. The passing vehicle data in the secondary additional data set is inserted into the final secondary queue set according to the same lane number and in chronological order for further correction. At this time, there are three situations: (1) If a vehicle in the secondary additional data set (which may be one or several consecutive vehicles) is between two vehicles in the secondary queue state, the vehicle is also marked as being in the secondary queue state.

[0086] (2) If the previous vehicle in the secondary additional data set (which may be one or several consecutive vehicles) is in a non-secondary queue and the next vehicle is in a secondary queue, the vehicle is marked as in a secondary queue based on the difference between the time when the secondary additional data vehicle enters the downstream intersection and the time when the previous vehicle (marked as a non-secondary queue vehicle) enters the downstream intersection. If the difference is greater than the minimum green light time, the vehicle is marked as in a secondary queue.

[0087] (3) If the vehicle in the secondary additional data set (which may be one or several consecutive vehicles) has a previous vehicle in the secondary queue and a subsequent vehicle in a non-secondary queue state, the vehicle is marked as being in the secondary queue state based on the difference between the time when the secondary additional data vehicle enters the downstream intersection and the time when the previous vehicle (marked as a non-secondary queue vehicle) enters the downstream intersection. If the difference is greater than the minimum green light time, the vehicle is marked as being in the secondary queue state.

[0088] After the correction is completed, a new final secondary queue set is obtained, which can obtain a more complete and accurate secondary queue situation of vehicles. In this embodiment, the vehicles in the secondary additional data set and the vehicles in the additional data set in embodiment 2 can be simultaneously inserted into the correction process of the final secondary queue set.

[0089] Then, the sample quantity threshold of the final secondary queuing set is set to m (such as 5 vehicles), and the ratio threshold is set to n (such as 0.25). That is, when the number of vehicle pairs marked as secondary queuing in the final secondary queuing set is greater than 5, and the ratio of the number of vehicle pairs in the final secondary queuing set to the number of process pairs in the primary screening data set is greater than 0.25, it indicates that a secondary queuing alarm is required.

[0090] Embodiment 4. Compared with Embodiment 3, this embodiment improves the method for screening and excluding the data of passing vehicles that are concentrated in adjacent intersections. Compared with the method of comparing and screening any two pairs of passing vehicles with the same flow direction entering the downstream intersection in Embodiment 3, this embodiment sorts the passing vehicles according to the time of entering the upstream intersection and the time of entering the downstream intersection, and screens the passing vehicle pairs whose travel time difference is greater than the time difference threshold in the order of first in and last out according to the sorting order, thereby saving the calculation amount of screening and comparison, and also enabling more thorough data cleaning.

[0091] A secondary queue warning method based on vehicle passing data, characterized by comprising: Obtain all the vehicle passing data at the checkpoints of a fixed time length, and match them to generate a dataset of vehicle pairs at adjacent intersections.

[0092] The data set of passing vehicles is filtered out to exclude the passing vehicle data that stops and stays between adjacent intersections, and a filtered data set is obtained.

[0093] As a specific example, Figure 4 The flowchart of screening the data of parked and stranded vehicles is shown. Based on matching and generating the vehicle pair data set of adjacent intersections, the vehicle pairs in the vehicle pair data set are arranged according to the time sequence of entering the upstream intersection, with the vehicle pairs entering the upstream intersection first being placed in front.

[0094] Starting from the first passing vehicle pair, traverse all the passing vehicle pairs in the passing vehicle pair data set, determine whether the time when the current passing vehicle pair enters the downstream intersection is later than the time when its subsequent passing vehicle pair data enters the downstream intersection, and determine whether the difference between the travel time of the current passing vehicle pair and the travel time of the corresponding passing vehicle pair is greater than the travel difference threshold when the time when the current passing vehicle pair enters the downstream intersection is later than the time when a subsequent passing vehicle pair enters the downstream intersection. If so, add the current passing vehicle pair to the intermediate data set until the judgment of all passing vehicle pairs is completed.

[0095] The vehicle pairs in the intermediate data set are arranged according to the time sequence of entering the downstream intersection, with the vehicle pairs that enter the downstream intersection first being placed in front.

[0096] Starting from the first passing vehicle pair in the intermediate data set, traverse all passing vehicle pairs, determine whether the time when the current passing vehicle pair enters the upstream intersection is earlier than the time when its subsequent passing vehicle pair data enters the upstream intersection, and determine whether the difference between the travel time of the current passing vehicle pair and the travel time of the corresponding passing vehicle pair is greater than the travel difference threshold when the time when the current passing vehicle pair enters the upstream intersection is earlier than the time when a subsequent passing vehicle pair enters the upstream intersection. If so, add the current passing vehicle pair to the first screening data set until the judgment of all passing vehicle pairs is completed.

[0097] The data is judged for secondary queuing according to the passing vehicles in the primary screening data set to obtain the initial secondary queuing set.

[0098] The vehicle queue state deviation caused by entering the waiting area in the initial secondary queue set is corrected to obtain the final secondary queue set.

[0099] When the data in the final secondary queue set meets the preset standard, a secondary queue alarm is issued. The sample quantity threshold of the final secondary queue set is set to m (such as 5 vehicles), and the ratio threshold is set to n (such as 0.25). That is, when the number of vehicle pairs marked as secondary queue in the final secondary queue set is greater than 5, and the ratio of the number of vehicle pairs in the final secondary queue set to the number of process pairs in the primary screening data set is greater than 0.25, it indicates that a secondary queue alarm is required.

[0100] The above embodiments are further elaborations and illustrations of the present invention for ease of understanding, and are not limitations of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A secondary queue warning method based on vehicle passing data, characterized in that: include: Obtain all the vehicle passing data of the checkpoints with a fixed time length, and match and generate a data set of vehicle pairs at adjacent intersections; The vehicle pair data set is filtered to exclude the vehicle data that stops and stays between adjacent intersections, and a filtered data set is obtained; Perform secondary queuing judgment on the data according to the passing vehicles in the primary screening data set to obtain an initial secondary queuing set; Correct the vehicle queue state deviation caused by entering the waiting area in the initial secondary queue set to obtain the final secondary queue set; When the data in the final secondary queuing set meets the preset standard, a secondary queuing alarm is issued.

2. The secondary queuing warning method based on vehicle passing data according to claim 1 is characterized in that: The matching and generation of the vehicle pair data set at adjacent intersections includes: Based on the data of vehicles passing through the checkpoint, all license plates are traversed and the data of the same license plate are arranged in chronological order; Match the vehicle data of the license plate on the road section between adjacent intersections, including the time of entering the upstream intersection and the time of entering the downstream intersection; Based on the flow direction corresponding to the lane where the vehicle enters the downstream intersection, the matching vehicle pair data for each flow direction is recorded.

3. A secondary queuing warning method based on vehicle passing data according to claim 1 or 2, characterized in that: The obtaining of the initial secondary queue set comprises: For each pair of vehicles in the filtered data set, calculate the travel time between adjacent intersections; Calculate the free flow travel time of the road sections between adjacent intersections based on the free flow speed of the road sections; In the first screening data set, the vehicle pairs whose travel time minus the free flow travel time is greater than the intersection signal cycle are determined to be secondary queues, and the initial secondary queue set is obtained.

4. A secondary queuing warning method based on vehicle passing data according to claim 1 or 2, characterized in that: The screening and exclusion of the passing vehicle data set includes the following passing vehicle data that stops and stays between adjacent intersections: For any two pairs of vehicles entering the downstream intersection with the same flow direction; The filter excludes the vehicle pair data that enters the upstream intersection earlier but enters the downstream intersection later, and the difference between the travel time and the travel time of another vehicle pair data exceeds the time difference threshold.

5. The secondary queuing warning method based on vehicle passing data according to claim 1 is characterized in that: The final secondary queue set is obtained by: The initial secondary queue is concentrated, divided by the lane where the vehicles enter the downstream intersection, and arranged in the order of time of entering the downstream intersection; For two adjacent pairs of vehicles in the same lane, if the current pair of vehicles is in secondary queuing and the next pair of vehicles is in non-secondary queuing, and the difference in travel time between the current pair of vehicles and the next pair of vehicles is less than the minimum green light time, the current pair of vehicles will be corrected to non-secondary queuing.

6. A secondary queuing warning method based on vehicle passing data according to claim 1, 2 or 5, characterized in that: The preset standards for the secondary queuing alarm include: The number of passing vehicle pairs in the final secondary queue set is greater than the sample quantity threshold, and Finally, the ratio of the number of passing vehicle pairs in the secondary queuing set to the number of passing vehicle pairs in the primary screening data set is greater than a preset ratio threshold.

7. The secondary queuing warning method based on vehicle passing data according to claim 2 is characterized in that: The matching and generation of the vehicle pair data set at adjacent intersections also includes: Corresponding to the checkpoint vehicle passing data within a fixed time length, if a license plate only matches the vehicle passing data of one intersection, the fixed time length is rolled back to expand the checkpoint vehicle passing data, and the vehicle passing data of the license plate is re-matched.

8. The secondary queuing warning method based on vehicle passing data according to claim 3 is characterized in that: Calculating the free flow travel time of a road section between adjacent intersections according to the road section free flow speed includes: Collect the historical vehicle speeds of sections between adjacent intersections within a fixed time period and arrange them in descending order, take the speed samples of a pre-set percentage and average them to obtain the free flow speed of the section; The free-flow travel time is obtained by dividing the length of the road section between adjacent intersections by the free-flow speed of the road section.

9. A secondary queue warning system based on vehicle passing data, applicable to the secondary queue warning method according to any one of claims 1 to 8, characterized in that: include: The vehicle passing data collection module collects the vehicle passing data at the checkpoints at the intersection; The matching and screening module matches and generates a data set of passing vehicles at adjacent intersections, and screens and excludes the passing vehicle data of parked vehicles; The queue evaluation module evaluates the secondary queue status of the passing vehicle data and obtains the initial secondary queue set; The correction module corrects the vehicle queue state deviation caused by the vehicle entering the waiting area for the initial secondary queue evaluation result.

10. The secondary queue warning system based on vehicle passing data according to claim 9 is characterized in that: The vehicle passing data collection module includes a collection unit arranged at each entrance of each intersection; The collection unit collects the time and lane information of the vehicle entering the intersection through the corresponding entrance; The intersection is an area surrounded by the parking lines of each entrance and their extension lines.

Images