71 results about "Saturation flow rate" patented technology

The invention discloses a reversible-lane-based intersection signal control method. The method comprises the following steps of, firstly, at eligible intersections, mounting detectors, and laying annunciators, main signal lights, pre-signal lights, reversible lane dynamic signs, wherein the annunciators are provided with computer programs, and the main signal lights, the pre-signal lights and the reversible lane dynamic signs are associated with reversible lanes; secondly, according to historical data, determining approaches where the reversible lanes can be arranged, and starting reversible lane control schemes; thirdly, according to the left turn and straight traffic flow of the approaches and the relation between the number of lanes and the saturation flow, judging the operating directions of the reversible lanes; lastly, according to the directions of the reversible lanes, determining appropriate signal matching schemes. The reversible-lane-based intersection signal control method can improve the traffic capacity of the intersections, reduce delay at the intersections and guarantee vehicle driving safety of the intersections.

The invention relates to a method for obtaining traffic status based on a sensor network and a device thereof. The method and the device adopt a transmission mode where a site bus is combined with a mass-data transmission network to form the sensor network for obtaining the traffic status. A sensor access node and a compound node have data processing capability. Such traffic status parameters, which reflect the traffic status at the section, as traffic flow, time occupancy factor, vehicle instantaneous speed, average speed at a section, and distribution feature of flow at the section over time, are obtained at the access node of the sensor network; fusion of logistic level is finished at the compound node to obtain such parameters reflecting zone traffic status as delay time, saturation flow rate, average queue length, average queue time at a road section, average driving time, average journey time, average driving speed, traffic coefficient, and average delay time at a small granule area; and fusion of business level is finished in a central computer to obtain such parameters reflecting large granule traffic status as average journey time at different routes, traffic coefficient at different routes and zone traffic jam degree.

An arbiter for a switch maintains a pair of counters for each flow of traffic at each input port: one counter (also called “first counter”) to indicate an ideal transfer of traffic, and another counter (also called “second counter”) to indicate the actual transfer of traffic. Both counters are incremented when traffic is received by the input port, and the second counter is decremented when a unit of traffic (such as a cell or packet) is about to be transmitted whereas the first counter is decremented in a fractional manner (relative to the unit of traffic) in each period of arbitration, based on available bandwidth. The arbiter selects one of the output ports (also called “winning output port”) of the switch, based at least partially on values of the two counters for each flow from the input port to one of the output ports, and generates a signal to approve transfer of traffic from the input port to the winning output port. In several embodiments, the above-described flow can be for either high priority traffic or for low priority traffic, and any bandwidth leftover from transferring high priority traffic is used in transferring low priority traffic. Specifically, the arbiter maintains additional counters for each port indicative of total bandwidth being used, and the additional counters are used to allocate leftover bandwidth in an iterative manner, until a flow from an input port to an output port is saturated, at which time the saturated flow is removed from iteration.

The invention discloses a correction method of bicycle impact on saturation volume rate of turning motor vehicles at a signalized intersection, which can be applied to calculating timing of signal control at the intersection. The correction method divides a conflict between bicycles and turning motor vehicles into two phases by studying different states of bicycles which cross the intersection and defines a conflict area; in the first stage, the gathered waiting bicycles during the red light period cross the intersection in the manner of bicycle groups with high density and low freedom, and the conflict is analyzed based on time occupation ratio of the conflict area by bicycles; in the second stage, bicycles arriving randomly at the intersection in a random manner with low density and high freedom, and the conflict is analyzed based on a crosscutting gap theory, and an influence coefficient of the bicycles on the saturation volume rate of turning motor vehicles is calculated. By applying the timing at intersection calculated by adopting the correction method of the bicycle impact on saturation volume rate of turning motor vehicles at a signalized intersection to the practice, the conflict between motor vehicles and non-motorized vehicles at the intersection can be relieved, traffic capacity of the intersection can be improved, and delay of motor vehicles at the intersection can be reduced.

The invention relates to a traffic overflow inhibition method based on high altitude video information. Compared with the prior art, the traffic overflow inhibition method based on the high altitude video information overcomes the defect that no automation inhibition method for solving the problem of traffic overflow exists in the prior art. The traffic overflow inhibition method based on the high altitude video information includes following steps: erecting a high altitude camera, and communicating the camera and a signal controller with an information center through a wired network or a wireless network; performing distance calibration on a camera image and actual distance of a road; setting overflow queuing length threshold value; calculating saturation flow and traffic capacity of a lane; calculating the maximum queuing length and saturation in each signal cycle of the lane; judging out a mapping relation of average increasing velocity and the saturation of the queuing length; forecasting a cycle reaching the overflow length threshold value; adjusting matching time of upstream and downstream signal lamps. The traffic overflow inhibition method based on the high altitude video information can grasp increasing and dissipating rules of the queuing length before the traffic overflow occurs, and forecasts an occurring cycle of the traffic overflow.

The invention discloses a hidden Markov chain based intersection real-time saturation flow rate estimation method. The method includes steps of a, collecting traffic flow data, including time headway itself, influencing saturation time headway; b, training parameters of a hidden Markov chain model through the collected traffic flow data; c, performing real time collection on time headway in front of a stop line of the intersection, estimating a hidden time headway state behind a time headway sequence and obtaining a continuous stable time headway sequence; d, averaging the stable time headway sequence and utilizing the reciprocal of the average value as the saturation flow rate corresponding to the stop line. The method provided by the invention can be used for real time estimation of the saturation flow rate and provides parameter basis for traffic control.

The invention discloses a crossroad traffic signal lamp real time dynamic timing method, relating to the road traffic control field. The crossroad traffic signal lamp real time dynamic timing method comprises steps of defining phases of various traffic flow directions of a crossroad, determining a saturation flow of each phase, measuring multiple current flows of each phase, obtaining a biggest current flow of each phase, calculating a relative biggest flow ratio of each phase and crossroad flow intensity, designing a target function and solving the target function to obtain a theoretical effective green light time of each phase, determining a signal lamp cycle time according to the theoretical effective green light time of each phase and crossroad signal lamp total loss time, and determining the practical effective green light time of each phase according to a ratio of the relative biggest flow ratio of each phase to crossroad flow intensity in the signal lamp cycle. The crossroad traffic signal lamp real time dynamic timing method avoids the fact that the vehicle starts and stops frequently in a congestion road due to the short cycle, improves a traffic capacity of the congestion road, reduces the parking rate of the congestion rate and has good robustness.

The invention discloses a single-point control method under dynamic traffic conditions. The relevant constraint and the input information of the intersection are constructed by combining the traffic states of the adjacent upstream and downstream intersections; the phase sequence conversion caused by the change of the traffic demand of the intersection is considered; the method for updating the time interval and the saturation flow of the saturated head is further considered, so as to ensure that the currently used data is the data closest to the current traffic state; the corresponding signalcontrol strategies are formulated for different traffic states, the problem that the solution difficulty is increased due to the fact that the models are complex is avoided, and meanwhile, the stability and the flexibility of the control scheme are comprehensively considered; and different tolerance saturation can be set for each phase according to experience, road weight and the like so as to adjust the signal control strength, so as to enhance the controllability of implementation.

The invention discloses a real-time calculating method for saturation flow rate of a signal intersection. The real-time calculating method comprises the steps of calculating a time headway of vehiclesin an inlet channel in a period; if the number of the vehicles in the inlet channel in the period is lower than a vehicle threshold, calculating the saturation flow rate of the inlet channel in the period by means of an empirical saturation time headway; if the number of the vehicles in the inlet channel in the period is higher than or equal with the vehicle threshold, setting a saturation time headway threshold interval according to the vehicle type, thereby obtaining the time headway in the saturation state; if the number of the vehicles in the saturation state of the inlet channel in the period is lower than the vehicle threshold in the saturation state, calculating the saturation flow rate of the inlet channel in the period through the empirical saturation time headway; if the numberof the vehicles of the inlet channel in the saturation state in the period is higher than or equal with the vehicle threshold in the saturation state, calculating the saturation time headway of the inlet channel in the period, and obtaining the corrected saturation flow rate of the inlet channel in the period through a mean value correction method. The real-time calculating method improves calculation accuracy and satisfies a requirement for dynamically extracting the saturation flow rate.

The invention discloses a channelizing and signal timing method of a three-entrance way intersection provided with a public transportation lane. The channelizing and signal timing method comprises the following steps of: step 10) judging whether a left turning lane and a right turning lane can satisfy a combining condition: when the combining condition is satisfied, combining the left turning lane and the right turning lane, and entering a step 20); when the combining condition is not satisfied, stopping judgment; step 20), determining a position of every lane of an entrance way; step 30), channelizing the intersection; step 40), determining saturated flow of every lane; step 50), performing Webster signal timing on a road: performing the Webster signal timing on the basis of every turning flow at the intersection obtained in step 10) and the saturated flow of every lane confirmed in step 40), and checking whether the shortest green light time length when passengers cross a street. By adopting the method, a problem of insufficient space caused by arranging the public transportation lane at a cross intersection is solved, and reduction of the public transportation lane on social vehicle traffic capacity is reduced.

The invention discloses an intersection signal optimizing control method in a heterogeneous traffic state. The method comprises the following steps that an intersection with heterogeneous traffic flow convergence serves as a research object, a video detector is installed on the intersection, and heterogeneous traffic characteristics of all entrance lanes are identified; a vehicle driving simulation model is established according to the heterogeneous traffic characteristics of all the entrance lanes, heterogeneous traffic flows are simulated, and saturation flows of all the entrance lanes are obtained; signal parameters are optimized on the basis of an all-phase equisaturation principle, and a signal timing plan of the intersection is obtained. By means of the intersection signal optimizing control method in the heterogeneous traffic state, maximum utilization of traffic capacity of the intersection can be achieved, delay of the heterogeneous traffic flows for passing through the intersection is greatly reduced, and the operating efficiency of the signal intersection is improved.

The invention discloses a saturation flow rate calculating method for an urban road intersection. The method includes collecting traffic data of the urban road intersection; performing pre-treatment on the traffic data and storing result data obtained through the pre-treatment; performing real time calculation according to a Grubbs algorithm and storing average time headway of the urban road intersection in single cycle; according to a K-means clustering algorithm, performing clustering analysis on the average time headway of the urban road intersection in single cycle in identical weather conditions and acquiring a clustering analysis result; calculating the mean value of time headway in a saturation condition and acquiring the saturation flow rate of the urban road intersection in different weather conditions. The method provided by the invention improves precision of the saturation flow rate of the urban road intersection in different weather conditions.

The invention discloses a signal timing optimization method of an intersection with a construction area. The method comprises the following steps: step 1, calculating the saturation flow rate of an island type construction area; step 2, calculating the time when the release rate state of the inlet channel changes; step 3, calculating the vehicle delay of the entrance road of the intersection; step4, calculating the phase emptying time under the condition of having the construction area; and step 5, establishing an objective function and solving an optimal solution as the signal timing in caseof having the construction area. The FVD model is improved and the saturation flow rate model of the island type construction area at the signal intersection is put forward. The island type construction area intersection signal optimization model is proposed on the basis of the vehicle arrival-departure delay model so as to ensure the traffic safety of motor vehicles and non-motor vehicles to themaximum extent at the intersection of the island type construction area. The island type intersection has better signal optimization and the passengers are ensured to have better travel experience.

An evaluation method for motor vehicle exhaust gas diffusion at a structured intersection comprises the following steps of: 1, calculating the intensity of an emission source of a road segment line source according to parameters such as traffic flow of vehicles passing through a road segment, the proportions of various vehicle models and an emission factor; 2, converting idling emission of a queuing road segment into the intensity of a virtual line source according to parameters such as traffic flow arrival rate of the traffic flow queuing road segment, traffic signal green ratio, lane saturation flow rate, the proportions of various vehicle models and the emission factor and with reference to a CAL3QHC mode of an intersection exhaust gas diffusion mode; 3, building a coordinate system by taking an intersection center as an original point, and calculating corresponding concentration component values CA, CB, CC and CD of an arbitrary receiving point in an intersection region on a plane with a height value z in intersections A, B, C and D respectively, wherein CA is in the intersection A and is the pollutant concentration far away from the virtual line source 1 by L1; 4, calculating the pollutant concentration C of the receiving point according to the concentration of two segments of street canyons and a wind angle Theta in an upwind direction of the receiving point in the intersections; and 5, acquiring the pollutant concentration value C of the receiving point of which the concentration is within the period.

The embodiment of the invention discloses a saturation flow determination method and a device, belongs to the intelligent transportation field, and is used for automatically reckoning the saturation flow value. The invention comprises the following steps: acquiring pulse data output by a detector at the inlet passage of the signal crossing; counting the car head time interval at the inlet passage; and determining the saturation flow value according to the counted car head time interval. Therefore, an automatic saturation flow reckoning scheme is realized.

The invention discloses a signal control plane intersection variable guiding lane attribute dynamic adjustment threshold value setting method. The method comprises the following steps: acquiring an intersection geometrical parameter, a signal control parameter and basic traffic data; calculating saturation flow rate of each lane of approaches before and after variation of the variable guiding laneattribute; establishing a variable guiding lane attribute variation threshold value setting model; solving a turn-left vehicle stream threshold value corresponding to a plurality of straight-going vehicle flow rates; performing data fitting, and generating a threshold value curve. The invention provides a dynamic adjustment threshold value setting method for a lane steering function of a variableguiding lane. The method can provide parameter basis for traffic control, is effectively adaptive to dynamic fluctuations of each steering traffic streams of approaches of intersections, and is beneficial for improvement and promotion of time-space resource of the intersections.

The present invention discloses an intersection signal time assignment method with a contraflow variable lane. The method comprises the following steps: 1) arranging a contraflow variable lane intersection ring structure signals phase sequence design; 2) determining the saturation flow of a contraflow variable lane; 3) setting contraflow variable lane intersection signal time assignment parameter calculation; 4) controlling the determination of variable constraint conditions; 5) constructing and solving a cooperation optimized objective function; and 6) outputting optimal signal control schemes. The intersection signal time assignment method with a contraflow variable lane fully considers the influence of arrangement of a variable lane on vehicles at an intersection, the signal phase sequence design is performed based on a ring structure, the minimum of the average vehicle delay time at the intersection and the contraflow variable lane starting time are taken as optimal targets, a cooperation optimized model of the contraflow variable lane control parameters and signal time assignment parameters is established, and an optimal contraflow variable lane and signal time assignment scheme is searched in the operation safety constraint condition so as to realize the maximum control benefit in the condition of the maximum safety of the contraflow variable lane.

An automated system and integrated method for traffic volume estimation that collects GPS data from available sources, furnished with the novel algorithm which uses and analyzes the information on road patterns and traffic signal timing along with the accumulated GPS data, and estimates the value of traffic volume for a road section which may consist of one or more segments on a basis of the values of travel times and probes collected from GPS sources available for each road segment, with the use of the saturation flow value, defined with the consideration of road geometry, traffic signal timing, and registered traffic events of traffic volumes for each timing interval for each section of the road in a road network.

The invention discloses a two-way two-lane highway construction area optimal construction length setting method. Firstly the traffic data of a construction road are acquired by aiming at the typical two-way two-lane national and provincial highway and county and township roads, including traffic flow arrival rate, speed and saturation flow rate, etc.; and delay cost, average construction time of the road per kilometer, the fixed cost of a single construction area and other parameters are inputted; secondly, total effective green light time of one period is calculated, and the effective green light time is allocated according to the principle of isosaturation; and queue clearance time of the maximum queue length point within the single period and the total vehicle delay within the period are accordingly calculated through combination with the traffic flow fluctuation theory; then the total delay cost of the vehicle and the fixed cost in the construction period are calculated; and finally a calculation model of the optimal construction length of the highway construction area is established. According to the method, the mathematical model is established to quantitatively calculate the optimal construction length of the construction area by using the mode of alternate releasing through signal control so that the traffic flow delay and the total cost can be reduced.

The invention provides a Gaussian process regression saturation flow rate detection method. The method comprises the steps that 1) original passing time data of a certain lane of an intersection at astop line during a period of interest are acquired; 2) the original passing time data are pre-processed to acquire passing time data; 3) instantaneous flow data and the passing time data in a cycle are calculated by using a timing scheme and the passing time data; 4) a Gaussian process regression method is used to fit an instantaneous flow rate curve based on the instantaneous flow rate data and the passing time data in the cycle; and 5) the maximum value of the instantaneous flow rate curve is solved and is used as the detection value of the saturation flow rate. Compared with the prior art,the method provided by the invention fully exploits intermittent traffic flow information contained in passing time big data at the stop line at the intersection, and acquires the saturation flow ratedetection value which is more accurate.

The invention discloses an intersection lane division detailed traffic parameter acquisition method based on double cameras. Due to the inherent defects of a single low-angle camera, two low-angle cameras with opposite visual angles are used for jointly monitoring the entrance road section of the intersection. Firstly, double cameras are installed at an entrance road section of an intersection, and offline setting of a region of interest is carried out; secondly, vehicle robust detection represented by a vehicle head and a vehicle tail is realized for each camera, and the position of each vehicle on each lane is divided by using stable features; after the exact time of the vehicle passing through the predetermined detection line and the parking line is further estimated, the real-time estimation of the cumulative curve of arrival and departure of the vehicle in different lanes can be realized. And finally, based on the cumulative input and output model, calculating traffic detail parameters such as the average arrival rate and the departure saturation flow rate of the divided lanes and the queuing length of the vehicles in the divided lanes by utilizing the arrival and departure cumulative curves of the vehicles in the divided lanes. The method has important significance in intelligent traffic monitoring and intersection traffic parameter acquisition.

The invention provides an intelligent rail transit main branch intersection traffic signal control method; a branch and main road flow ratio and an intersection total flow and saturation flow ratio are taken as input, an initial signal period is calculated through a fuzzy controller, and calculation is carried out through a Webster timing method to obtain a complete signal timing scheme; by arranging a special lane-borrowing indicator lamp, when an intelligent rail runs, inductive adjustment is carried out on intersection signal timing; and when the intelligent rail does not run, other motor vehicles are allowed to run by borrowing a lane. Simulation test results show that compared with fixed timing and pure fuzzy control, the method better adapts to signal control when the intelligent rail passes through the intersection of a trunk road and a branch road. According to the method, evaluation indexes such as the vehicle queuing length, the average delay and the parking frequency are improved, the carrying capacity of urban public transport and the control efficiency of the mixed flow of the vehicle with the intelligent rail are improved, and a research basis is provided for automatic driving and manual driving mixed traffic flow to pass through the intersection of the main road and the branch road.

The invention provides a system, a method and a device for determining traffic saturation, and relates to the field of traffic signal lamp control. The method includes acquiring vehicle occupation data in red lamp phase durations; determining demand traffic volumes of corresponding lanes of to-be-detected phase according to comparison results of occupation time of the vehicle occupation data and preset occupation time; determining the traffic saturation according to the demand traffic volumes of the corresponding lanes of the to-be-detected phase, saturation flow rates and timing information of signal periods to which the red lamp phase durations belong. The vehicle occupation data are transmitted by upstream detectors in the corresponding lanes of the to-be-detected phase. The traffic saturation corresponds to the to-be-detected phase. The system, the method and the device have the advantages that separate point detectors of the corresponding lanes of the to-be-detected phases and thetiming information of the signal periods corresponding to the to-be-detected phase are combined with one another, accordingly, the traffic demand volumes of the corresponding lanes of the to-be-detected phase can be accurately measured, and the computational accuracy of the traffic saturation can be improved.

The invention discloses a lane function division method and device, electronic equipment and a storage medium. The method comprises the following steps: determining a sum value of green light time ina single period of a lane with each function, and taking a product of a specific value of flow and quantity of the lane with the function and the sum value as effective green light time of the lane with the function for the lane with each function; according to the effective green light time of the lane of each function, a preset single-lane saturation flow rate, a preset signal lamp period lengthand a traffic capacity parameter calculation formula, determining the target number of each lane when the traffic capacity parameter takes the maximum value; and performing lane function division according to the target number of each lane. When lane function division is carried out according to the target number of each lane, the traffic capacity of the intersection is optimal, so that a problemof intersection congestion is solved to the greatest extent.

The invention provides a calculation method for the saturation flow rate of lanes based on electronic police data. A highly efficient and precise method is provided for acquisition and processing of timing data of signal lights at an intersection. Firm data support is provided for optimization of the timing of signal lights at the intersection. The calculation method plays an important role in improving of efficiency of intersection signal timing schemes, and in improving implementation effects of urban traffic control and operation efficiency of the whole traffic system. According to the invention, in the calculation of the lanes, the time headway and the saturation flow rate are used as important factors in determination of periods of signal timing; by differentiating weather factors like sunny days, rainy days and snowy days, based on a large number of history data, precise data calibration is performed on parameters; functions of big data are fully played in calibration of the parameters; and data basis is provided for precise scene type signal timing.

The invention discloses a debugging method for improving the failure working mode consistency of triplex-redundancy servo valves. The debugging method comprises the following steps of (1) conducting debugging to improve the failure state saturation flow before starting of first-redundancy failure debugging or when the first-redundancy failure flow curve of the redundancy servo valves is saturatedand the saturation flow is reduced obviously; (2) conducting debugging to improve the flow curve linearity when the redundancy servo valve first-redundancy failure flow curve has a turning point wherethe flow grain suddenly increases; and (3) conducting debugging to improve the consistency of different channel first-redundancy failure flow curves when the problems that different channel first-redundancy failure flow curve gains or inconsistent linearity occur to the redundancy servo valves arise. Through the debugging method, the servo valves can be debugged in a targeted mode, the debuggingefficiency is improved, and the good performance of the servo valves under the failure working state and the consistency of the working performance of the servo valves in different working modes are ensured.

The embodiment of the invention provides an information processing method and device, a traffic control method and device, equipment and a storage medium. The information processing method comprises the steps that at least one traffic phase set at a traffic intersection is determined; the saturation flow rate and the traffic demand of each traffic phase are determined, wherein the saturation flowrate represents the maximum traffic flow in unit time corresponding to each traffic phase, and the traffic demand represents the traffic flow actually required to be passed and corresponding to each traffic phase; the effective passing time of each traffic phase is obtained through calculation by utilizing the traffic demand and the saturation flow rate of each traffic phase; and the signal periodof the traffic intersection is obtained according to the respective effective passing time of the at least one traffic phase. According to the technical scheme provided by the embodiment of the invention, the accuracy of the traffic intersection signal period is improved.

The invention discloses a vehicle queuing length estimation method based on Kalman filtering in an Internet of Vehicles environment. The method is applied to the technical field of traffic engineering, and aims to solve the problems that an existing Kalman filtering method cannot provide estimation of second-level queuing length in queue length estimation and does not fully utilize real-time Internet of Vehicles data. The method comprises the following steps: estimating traffic volume, saturated flow and permeability according to the Internet of Vehicles trajectory data; and then, consideringthe estimation error, proposing a Kalman filtering method to estimate the queuing length in real time based on the estimated parameters (namely traffic volume, saturated flow and permeability) and traffic signal timing data. According to the method provided by the invention, second-level queuing length estimation can be realized, and the method has very important significance for evaluating the traffic signal performance and optimizing the traffic signal timing.

The invention provides an adaptive signal control optimization method for an urban main and branch intersection. The method comprises the following steps: establishing a combined algorithm based on fuzzy control and machine learning, determining a signal period according to a real-time saturation flow rate (RS) and a flow change ratio (RR) of the intersection, and calculating according to a Q-learning algorithm to obtain the green light duration of each phase. The method can adaptively optimize the time length of the signal lamp at the main and branch intersection of the city according to the change of the traffic operation environment, improves the traffic efficiency, safety and stability of the traffic flow at the intersection, saves the manual intervention cost, and is wide in application range and easy to popularize.

The invention relates to a signal control intersection traffic capacity determination method considering man-machine mixed driving traffic flow. The method comprises the following steps: S1, setting that a traffic flow in an intersection comprises two types of motor vehicles including human-driven vehicles and intelligent network connection automatic driving vehicles; S2, obtaining the occupancy rates of HDV and CAV; S3, obtaining operation indexes such as saturation flow rates, green light loss time and the like of the HDV and the CAV through actual measurement; S4, obtaining running indexes such as the saturation flow rate and the like in a lane through actual measurement; S5, obtaining the saturation flow rate and the green light loss time of the man-machine mixed driving traffic flow at the signal control intersection; S6, obtaining a probability distribution function of the traffic capacity of the signal control intersection considering the man-machine mixed driving traffic flow; and S7, adopting deterministic expression and probabilistic expression as an expression mode of the traffic capacity. According to the invention, the heterogeneous traffic flow of man-machine mixed driving is considered, the essence of the traffic capacity of the intersection can be reflected, and the probabilistic expression of the traffic capacity is innovatively given.