177 results about "Time headway" patented technology

The present invention extends to methods, systems, and computer program products for monitoring signalized traffic flow. A processor in a sensor system or traffic controller interface estimates the time-of-arrival and other traffic flow estimates of one or more vehicles to an intersection stop bar, while the vehicles are within a continuous range of one or more transducers view of the sensor system. A level of efficiency and safety within the signalized traffic flow is estimated by the sensor system based upon one or more of the estimated time-of-arrival and other flow variables estimates and then communicated to the control unit of the traffic signal system. Other flow estimates for each vehicle include but are not limited to: position relative to the stop bar, lane position, velocity, acceleration, time headway and classification.

The invention discloses an automotive adaptive cruise control method taking multiple targets into consideration. A layer control strategy is utilized, upper layer control can decide an expected longitudinal acceleration according to a target vehicle and a current state of a controlled vehicle, and lower layer control can track the expected longitudinal acceleration through a reverse recursion method. The automotive adaptive cruise control method comprises the following steps: a mutual longitudinal dynamitic model between two vehicles is established, a design model predicating controller can obtain the expected distance between two vehicles according to a constant time headway strategy, a model prediction control algorithm is utilized to decide an expected longitudinal acceleration for tracking the expected distance between the two vehicles, vehicle control work conditions are divided into a driving work condition and a braking work condition, reverse longitudinal dynamic models for the two work conditions are established respectively according to a vehicle driving equation, an expected throttle percentage is obtained according to the vehicle reverse longitudinal dynamic model and the expected acceleration in the driving work condition, and an expected brake pedal openness is obtained according to the expected acceleration in the braking work condition.

A computer-implemented method for controlling a host vehicle having a vehicle control system that controls motion of the host vehicle relative to a preceding vehicle that is immediately ahead of the host vehicle. The method includes determining a relative headway distance and a relative velocity between the host vehicle and the preceding vehicle, and an acceleration rate of the preceding vehicle. The method includes receiving message packets transmitted from a leading vehicle and the message packets contain parameters of the leading vehicle including an acceleration rate of the leading vehicle. Further, the method includes calculating an acceleration control rate for the host vehicle to maintain the headway reference distance between the host vehicle and the preceding vehicle, based on the relative headway distance, the relative velocity, the acceleration rate of the preceding vehicle, and the acceleration rate of the leading vehicle. The acceleration rate is output to a vehicle controller to control motion of the host vehicle.

A control unit sets a front-end collision risk of a subject vehicle against a front vehicle in accordance with a time headway of the subject vehicle and a margin time to front-end collision of the subject vehicle, and a rear-end collision risk of the subject vehicle by a rear vehicle in accordance with a time headway of the rear vehicle and a margin time to rear-end collision of the subject vehicle, the margin time to rear-end collision having a larger weight than that of the margin time to front-end collision in the front-end collision risk against the front vehicle. Brake control and alarm control are performed in accordance with the front-end collision risk against the front vehicle and the rear-end collision risk by the rear vehicle.

The invention relates to a method for acquiring the mean delay of an urban road junction. The method comprises the following steps of: (1) double section selection: firstly, respectively mounting a plurality of cameras at an inlet passage and an outlet passenger of a junction, and then drawing a virtual detection frame used for detecting vehicles; (2) vehicle detection and traffic flow counting: carrying out information acquisition by utilizing the virtual detection frame, and carrying out vehicle detection in each frame of an acquired video; (3) queue length calculation: detecting the changes of time headway by adopting the virtual detection frame so as to distinguish queue vehicles and non-queue vehicles; and (4) delay value calculation according to a one-to-one principle: calculating according to last data in a inlet passage detector recording list, adopting a calculation policy and eliminating an accumulated error so as to ensure that an error is controlled within the range of theperiod without influencing other periods. The invention has the advantages of simple and convenient calculation, high operation speed, good stability, high reliability, and the like.

The invention discloses an intersection signal timing optimization method based on the queue length of vehicles. The maximum queue length is calculated according to the queue length of the vehicles at the end of a red light, according to the maximum queue length, green time required by a phase position is calculated, according to the green time of the phase position, a signal timing dual-loop structure is optimized, and a nesting phase position is made; compared with classical time-headway-based inductive control, the method obtains a better effect, is not sensitive to queue length error estimation, and can still obtain a good control effect even if some errors exit.

The invention relates to a vehicle adaptive cruise control method, device and system and an automobile in order to solve a problem of too small vehicle following time headway caused by acceleration control overshoot and response delay during vehicle following. The vehicle adaptive cruise control method comprises the steps of obtaining an actual vehicle speed and an actual accelerated speed, an actual vehicle speed of a target vehicle in front of a vehicle, an actual vehicle following distance between the vehicle and the target vehicle and an expected vehicle following time headway input by a user; determining a target accelerated speed of the vehicle according to the actual vehicle speed of the vehicle, the actual vehicle following distance, the actual vehicle speed of the target vehicle and the expected vehicle following time headway input by the user; determining whether the vehicle is in a starting crawling vehicle following condition or not according to the actual accelerated speedand the target accelerated speed; if the vehicle is in the starting crawling vehicle following condition, calculating an accelerated speed reducing amount according to the actual accelerated speed and the target accelerated speed; and controlling a brake system of the vehicle to perform braking moment control according to the accelerated speed reducing amount.

The invention provides an intersection dynamic signal timing optimization method based on time headway. The method comprises the following steps: 1, according to monitored vehicle passing data, an intersection phase ID is acquired; 2, a lane group is defined, that is, in the certain phase, all lanes with right of way in the same road section are defined as one lane group; 3, a core release lane in the phase is searched in the lane group, and if all phases of a lane have the right of way, the lane is removed from the lane group; 4, the flow of each lane in the lane group is calculated; 5, the time headway for phase key lanes in one period is acquired; and 6, the phase waste time is calculated, and the time of a green light is correspondingly adjusted. Through the time headway change in one period, an intersection passing signal timing scheme is analyzed, the corresponding given timing scheme is dynamically optimized in real time, and an important role is played in improvement of the operation efficiency of the whole traffic system.

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.

Provided is a full-induction type comprehensive vehicle waiting control method, which is targeted for a cross intersection, entrance lanes and exit lands of which cannot be expanded, and is characterized by carrying out traffic operation organization by utilizing 2 main signal phases, 4 pre-signal phases and 2 pedestrian phases, establishing two kinds of alternative phase display orders, summarizing 6 green light time distribution principles, arranging a near-end detector and a far-end detector for each lane in the upstream of a main signal stop line in each entrance direction, collecting time headway data in real time, managing green light time of the pre-signal phases according to judgment results of five traffic incidents and managing green light time of the main signal phases according to the judgment results of the five traffic incidents. The method can help drivers understand instructions of traffic control facilities correctly, makes full use of pass space resources of a comprehensive vehicle waiting area, and gives a quick response to dynamic changes of pass demands of motor vehicles, thereby facilitating eliminating traffic accident hidden troubles and improving pass efficiency of the intersection.

The invention discloses a method for predicting bus passenger waiting time range based on IC card data. The method comprises the following steps: step 1, a sample set is created; step2, RVM is modeling and the parameter calibration thereof are performed, steps, the time headways of the Bus A and Bus B on the second target station are predicted; the biggest characteristic of the invention comprises that the method can predict that the next bus which will arrive at some station at some point to some point, the blank of the bus arrival time range prediction is filled, the method has great innovative significance, and provides a more reasonable prediction method than the other patents; the method adopts IC card data to extract a mass of passenger information from a plurality of buses without using the vehicle-mounted GPS, the method is convenient and fast, the data processing cost is reduced, the IC card data can obtain the number of people who get on or off the bus at every station, so that the bus stay time at every station is obtained, and the above number and time can not be provided by the GPS data.

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 method for calculating the traffic capacity in a city expressway entrance interlacing region, and aims at filling a gap that there is short of a calculation method for effectively estimating the traffic capacity. The method comprises the following steps: 1, collecting related traffic parameters of an expressway interlacing region: 1), the mean time headway (shown in the description) of the traffic flow of an expressway trunk line Ls; 2), a critical time gap tC which allows ramp vehicles to merge into the expressway trunk line Ls; 3), the time headway th between two ramp vehicles; 4), the flow Q of the expressway trunk line Ls; 5), the distance L between a nasal tip N and a merging point of an accelerating vehicle La; 6), the design speed V1 of the expressway trunk line Ls; 7), the design speed V of a ramp; 2, calculating the probability distribution parameter K of the time headway of the expressway trunk line Ls; 3, building a method for calculating the traffic capacity of the ramp R; 4, improving the method for calculating the traffic capacity of the ramp R; 5, calculating the traffic capacity of the interlacing region through employing a formula (shown in the description), wherein CM is the traffic capacity of the interlacing region, the unit is vehicles/hour, and delta t is the time different of the ramp vehicle M2 and a trunk line vehicle M1 (unit is second).

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 time headway-based road vehicle change model calibration method, a time headway-based road vehicle lane change decision making method and a device. The vehicle lane change model calibration method comprises the steps of obtaining measured data of a vehicle and a road, wherein the measured data comprises the fact whether the lane of the vehicle has adjacent lanes or not, distances between the vehicle and vehicles in the front and rear on the same lane and the adjacent lanes and speeds of related vehicles; determining a lane change direction and determining whether a lane change motive exists or not and a target lane according to a time headway; constructing a time headway-based logistic vehicle lane change model; and extracting condition data indicating lane changesuccess and lane change rejection of a target vehicle so as to calibrate the vehicle lane change model. The time headway-based road vehicle change model calibration method is low in complexity, strong in applicability, less in data quantity demand, high in calculation efficiency and good in simulation effect, is capable of obtaining reliable vehicle lane change models through less measured data of vehicles and roads to simulate vehicle lane change behaviors, thereby researching the vehicle lane change behaviors, predicting the traffic flow states and providing help to ease the traffic congestion, decrease the hidden trouble of traffic and reduce the resource waste.

The invention discloses an expressway variable speed limit control system and method for rear-end collision risk prevention and control, and relates to an expressway variable speed limit control system and method. The objective of the invention is to solve a problem that the highest speed limit of the expressway cannot be dynamically controlled because the influence of the traffic state on the traffic safety is not considered in the setting of the highest speed limit of vehicles on the expressway. The system comprises an information detection module, a control module and an information releasemodule. The information detection module is used for detecting a section traffic flow, occupancy, a vehicle speed, acceleration and time headway data of a road section in real time and feeding back the data to the control module; the control module is used for receiving the data detected by the information detection module, judging the rear-end collision risk level of the road section, calculating the highest speed limit value of the road section and outputting the highest speed limit value to the information release module; and the information release module is used for publishing the highest speed limit value and early warning information of the road section in real time, prompting a driver to adjust the driving speed in time and ensuring driving safety. The invention belongs to the field of traffic safety.

The invention provides a collecting method for road traffic parameters based on a video technique, in order to overcome the defects of the prior art of low detection accuracy and poor environmental adaptation. The parameters contain flow, time average speed, time occupancy, average time headway, and the like. A pattern drawn in a detection area has better relative brightness combined mode consistency under different light environments, so that the methods of background difference, inter-frame difference, and the like, need not to be adopted when the road traffic parameters are collected. Meanwhile, the operand is less and the detection precision and environmental stability are higher.

The invention discloses a detection system for the unlawful act of using cell phones while driving. The detection system is arranged on a road and can be used for automatically detecting the suspected unlawful vehicles, the drivers of which use cell phones while driving; through comparing the interrelation of the time headways between the front and back adjacent vehicles on the same lanes in the traffic flow, the suspected unlawful vehicles, the drivers of which use cell phones while driving are identified; meanwhile, two identification coefficients of the vehicles, the drivers of which use cell phones while driving are obtained according to the test result and the unlawful act is judged preliminarily; the picture information of the suspected unlawful vehicles are sent to a manual screening platform; therefore, the manual screening workload can be reduced, and the efficiency and the judging accuracy can be improved.

The invention discloses a single-point intersection signal timing plan evaluation method in an unsaturated state and belongs to the technical field of traffic control. The method includes obtaining measured values of different evaluation indexes before and after signal timing plan optimization in the unsaturated state, wherein each evaluation index includes time headway and delay; according to the measured values of the different evaluation indexes before and after signal timing plan optimization, calculating the difference values of the indexes before and after optimization on different phases of a single-point intersection; according to the difference values of the indexes before and after optimization on the different phases of the single-point intersection, evaluating the optimization directions of the different phases in the signal timing plan. According to the invention, by taking the time headway and the delay on the different phases of an entrance way of the single-point intersection as the evaluation indexes of the signal timing plan in the unsaturated state, the optimization directions of the phases can be indicated clearly and an optimized step size is obtained, so that the signal timing plan can be optimized according to the optimization directions of the different phases and phase utilization rate can be increased.

The invention discloses a congested road section intelligent network connection vehicle special lane control method based on traffic simulation, which comprises the following steps of: acquiring basic traffic parameters such as road section traffic capacity, speed, time headway and the like and correlativity thereof, and detecting road traffic flow density and intelligent network connection vehicle permeability; determining a road section congestion critical condition, and judging a road section traffic state; adjusting the layout scheme of the special road for the intelligent networked vehicles, and calculating the traffic density of the road section and the permeability of the intelligent networked vehicles after the layout scheme of the special road is adjusted; according to the road section traffic density and the intelligent network connection vehicle permeability, simulating the road section traffic flow operation state; and by taking the minimum total passing time of the road vehicles as an optimization target, searching an optimal control parameter, and determining a layout control scheme of the intelligent network connection vehicle special lane of the congested road section. The intelligent network vehicle special lane is adjusted in time, the total traffic capacity of road vehicles is minimum, traffic congestion is relieved, and the operation efficiency of a traffic system is improved.

The invention discloses an integrated road traffic information acquisition system including a noise monitoring unit, a video traffic flow detection unit, a data processing and storage unit and a background management unit; the noise monitoring unit records the traffic noise data including weighted sound pressure level data, statistical sound pressure level data and spectral data, and the video traffic flow detection unit is used for acquiring the traffic flow, speed, vehicle type, time headway and other traffic data in real time. The data processing and storage unit is used for storing the traffic noise data acquired by the noise monitoring unit and the traffic flow data acquired by the video traffic flow detection unit. The background management unit is used for performing interactive operation with the data center and the monitoring terminal to localize the instructions of the monitoring terminal and the data center. The integrated road traffic information acquisition system has the characteristics of simple structure, high automation, and all-weather monitoring, can synchronously acquire the traffic noise data and traffic flow data in real time, and provides a large amount of basic data for the road traffic noise source strong emission model.

The invention discloses a method for determining alignment consistency characteristic parameters of tunnel entrances and exits under a dynamic driving environment. The method includes the steps: 1, averagely dividing a tunnel entrance-exit connection section and a tunnel entrance-exit interior into a plurality of zones by taking an entrance or an exit as an origin; 2, measuring illuminance changes of each zone in daytime and at night; 3, calculating a time headway T (L) between two vehicles; 4, calculating average passage time t, 5, selecting a maximum tmax; 6, calculating an initial alignment consistency time T''; 7, calculating final alignment consistency characteristic parameters. By the method for determining the alignment consistency characteristic parameters of the tunnel entrances and exits under the dynamic driving environment, a 'people-vehicle-road-environment' traffic circulation system is effectively harmonized, tunnel entrance-exit alignment consistency time is determined based on a safety headway model, driving alignment requirements are met on the basis of consideration of visual characteristic of drivers, and accordingly driving safety is guaranteed, precision of construction requirements and tunnel design standards can be improved, safety, smoothness and comfort in passing through of tunnels can be guaranteed for the drivers, and accident rate is decreased.