WO2020124305A1

WO2020124305A1 - Systems and methods for determining traffic conditions

Info

Publication number: WO2020124305A1
Application number: PCT/CN2018/121408
Authority: WO
Inventors: Jianfeng Zheng; Weili SUN; Xianghong Liu
Original assignee: Beijing Didi Infinity Technology And Development Co., Ltd.
Priority date: 2018-12-17
Filing date: 2018-12-17
Publication date: 2020-06-25

Abstract

A method for presenting traffic information of a road segment to a user is provided. The method may include obtaining historical track data of a plurality of vehicles that passed the road segment over a period (702), wherein the road segment is linked by an upstream intersection and a downstream intersection; obtaining a cycle pattern of a first traffic light and a cycle pattern of a second traffic light (704), the first traffic light being located at the downstream intersection, the second traffic light being located at the upstream intersection; determining a time-space diagram related to the road segment based on the historical track data of a plurality of vehicles, the cycle pattern of the first traffic light, and the cycle pattern of the second traffic light (706); and generating a graphic user interface for providing the time-space diagram to the user (708).

Description

SYSTEMS AND METHODS FOR DETERMINING TRAFFIC CONDITIONS

TECHNICAL FIELD

The present disclosure generally relates to systems and methods for monitoring road conditions, and in particular, systems and methods for monitoring traffic conditions.

BACKGROUND

With more and more vehicles on the street in urban areas, traffic congestion becomes part of people’s daily lives. Thus, it may be desirable to monitor traffic conditions such as congestion on the street. The traditional traffic monitoring mainly uses fixed cameras such as intersection cameras and induction coils buried in the ground to collect data on the number and speed of vehicles passing through. This monitoring method can only analyze the road conditions within a limited range. The equipment collecting and analyzing the data also consume a lot of computing power and manpower as well as material resources. It may, therefore, be desirable to develop more efficient methods to monitor traffic conditions.

SUMMARY

According to an aspect of the present disclosure, a method for presenting traffic information of a road segment to a user is provided. The method may be implemented on at least one machine each of which has at least one processor and storage. The method may include obtaining, from a server, by the one or more processors, historical track data of a plurality of vehicles that passed the road segment over a period, wherein the road segment is linked by an upstream intersection and a downstream intersection; obtaining, by the one or more processors, a cycle pattern of a first traffic light and a cycle pattern of a second traffic light, the first traffic light being located at the downstream intersection, the second traffic light being located at the upstream intersection; determining, by the one or more processors, a time-space diagram related to the road segment based on the historical track data of a plurality of vehicles, the cycle pattern of the first traffic light, and the cycle pattern of the second traffic light, wherein the time-space diagram includes: a first graphic representation indicating to the cycle pattern of the first traffic light, a second graphic representation indicating to the cycle pattern of the second traffic light, and a third graphic representation indicating a length of a queue on the road segment formed by one or more vehicles of the plurality of vehicles; and generating, by the one or more processors, a graphic user interface for providing the time-space diagram to the user.

In some embodiments, the third graphic representation may include a first section; and determining the time-space diagram may include: determining, by the one or more processors, a free-flow speed of the road segment based on the historical track data of the plurality of vehicles; and determining, by the one or more processors, the first section based on the free-flow speed of the road segment.

In some embodiments, the third graphic representation may include a second section; and determining the time-space diagram may further include determining, by the one or more processors, a back-propagation wave speed of the road segment based on the historical track data of the plurality of vehicles; and determining, by the one or more processors, the second section based on the back-propagation wave speed of the road segment.

In some embodiments, the third graphic representation may include a third section, and determining the time-space diagram may further include: determining, by the one or more processors, a last vehicle in the queue based on the historical track data of the plurality of vehicles; and determining, by the one or more processors, the third section based on a position of the last vehicle in the queue.

In some embodiments, the third section may be parallel to the first graphic representation or the second graphic representation.

In some embodiments, the method may further comprise: determining, by the one or more processors, whether a length of the third section of the third graphic representation is greater than or equal to a length the first graphic representation or a length of the second graphic representation of the time-space diagram; and displaying a visual representation relating to the third section based on a result of the determination that the length of the third section of the third graphic representation is greater than or equal to the length the first graphic representation or the length of the second graphic representation of the time-space diagram.

In some embodiments, the method may further comprise: determining, by the one or more processors, a duration of the queue based on a length of the third section, wherein the visual representation includes an indicator indicating the duration of the queue.

In some embodiments, determining the free-flow speed of the road segment may comprise: determining, by the one or more processors, a first parameter corresponding to a first status of the road segment based on the historical track data of the plurality of vehicles, wherein the first status is that a vehicle flow rate of the road segment is positively correlated to a vehicle density of the road segment corresponding to the vehicle flow rate; and determining, by the one or more processors, the free-flow speed based on the first parameter.

In some embodiments, determining the back-propagation wave speed of the road segment may comprise: determining, by the one or more processors, a second parameter corresponding to a second status of the road segment based on the historical track data of the plurality of vehicles, wherein the second status is that a vehicle flow rate of the road segment is negatively correlated to a vehicle density of the road segment corresponding to the vehicle flow rate; and determining, by the one or more processors, the back-propagation wave speed based on the second parameter.

In some embodiments, the historical track data of the plurality of vehicles may include historical track data determined by and obtained from a user terminal located in a vehicle.

According to an aspect of the present disclosure, a system configured to present traffic information of a road segment to a user is provided. The system may include at least one non-transitory storage medium including a set of instructions; and at least one processor in communication with the at least one non-transitory storage medium. When executing the set of instructions, the at least one processor may be configured to obtain, from a server historical track data of a plurality of vehicles that passed the road segment over a period, wherein the road segment is linked by an upstream intersection and a downstream intersection; obtain a cycle pattern of a first traffic light and a cycle pattern of a second traffic light, the first traffic light being located at the downstream intersection, the second traffic light being located at the upstream intersection; determine a time-space diagram related to the road segment based on the historical track data of a plurality of vehicles, the cycle pattern of the first traffic light, and the cycle pattern of the second traffic light, wherein the time-space diagram includes: a first graphic representation indicating to the cycle pattern of the first traffic light, a second graphic representation indicating to the cycle pattern of the second traffic light, and a third graphic representation indicating a length of a queue on the road segment formed by one or more vehicles of the plurality of vehicles; and generate a graphic user interface for providing the time-space diagram to the user.

According to still another aspect of the present disclosure, a non-transitory computer readable medium embodying a computer program product, the computer program product comprising instructions configured to cause a computing device to perform a method. The method may include obtaining, from a server, by the one or more processors, historical track data of a plurality of vehicles that passed the road segment over a period, wherein the road segment is linked by an upstream intersection and a downstream intersection; obtaining, by the one or more processors, a cycle pattern of a first traffic light and a cycle pattern of a second traffic light, the first traffic light being located at the downstream intersection, the second traffic light being located at the upstream intersection; determining, by the one or more processors, a time-space diagram related to the road segment based on the historical track data of a plurality of vehicles, the cycle pattern of the first traffic light, and the cycle pattern of the second traffic light, wherein the time-space diagram includes: a first graphic representation indicating to the cycle pattern of the first traffic light, a second graphic representation indicating to the cycle pattern of the second traffic light, and a third graphic representation indicating a length of a queue on the road segment formed by one or more vehicles of the plurality of vehicles; and generating, by the one or more processors, a graphic user interface for providing the time-space diagram to the user.

Additional features will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and the accompanying drawings or may be learned by production or operation of the examples. The features of the present disclosure may be realized and attained by practice or use of various aspects of the methodologies, instrumentalities, and combinations set forth in the detailed examples discussed below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is further described in terms of exemplary embodiments. These exemplary embodiments are described in detail with reference to the drawings. These embodiments are non-limiting exemplary embodiments, in which like reference numerals represent similar structures throughout the several views of the drawings, and wherein:

FIG. 1 is a schematic diagram illustrating an exemplary system for determining traffic conditions according to some embodiments of the present disclosure;

FIG. 2 is a schematic diagram illustrating components of an exemplary computing device according to some embodiments of the present disclosure;

FIG. 3 is a schematic diagram illustrating hardware and/or software components of an exemplary mobile terminal according to some embodiments of the present disclosure;

FIG. 4 is a block diagram illustrating an exemplary processing engine according to some embodiments of the present disclosure;

FIG. 5A is a schematic diagram illustrating an exemplary one-way road network according to some embodiments of the present disclosure;

FIG. 5B illustrates a diagram illustrating exemplary relationships between the traffic flow rate of a road segment and the traffic density of the road segment;

FIGs. 6A and 6B are schematic diagrams illustrating exemplary time-space diagrams according to some embodiments of the present disclosure.

FIG. 6C is a schematic diagram illustrating exemplary queue length trajectories in spillover according to some embodiments of the present disclosure;

FIG. 6D is a schematic diagram illustrating an enlarged view of an exemplary queue length trajectories in spillover according to some embodiments of the present disclosure;

FIG. 6E is a schematic diagram illustrating exemplary queue length trajectories in spillover according to some embodiments of the present disclosure;

FIG. 6F is a schematic diagram illustrating an enlarged view of an exemplary queue length trajectories in spillover according to some embodiments of the present disclosure;

FIG. 7 is a flowchart illustrating an exemplary process for presenting traffic information of a road segment to a user according to some embodiments of the present disclosure;

FIG. 8 is a flowchart illustrating an exemplary process for generating a time-space diagram according to some embodiments of the present disclosure; and,

FIG. 9 is a schematic diagram illustrating an exemplary graphic user interface for providing a time-space diagram to the user.

DETAILED DESCRIPTION

In order to illustrate the technical solutions related to the embodiments of the present disclosure, brief introduction of the drawings referred to in the description of the embodiments is provided below. Obviously, drawings described below are only some examples or embodiments of the present disclosure. Those having ordinary skills in the art, without further creative efforts, may apply the present disclosure to other similar scenarios according to these drawings. Unless stated otherwise or obvious from the context, the same reference numeral in the drawings refers to the same structure and operation.

As used in the disclosure and the appended claims, the singular forms “a, ” “an, ” and “the” include plural referents unless the content clearly dictates otherwise. It will be further understood that the terms “comprises, ” “comprising, ” “includes, ” and/or “including” when used in the disclosure, specify the presence of stated steps and elements, but do not preclude the presence or addition of one or more other steps and elements.

Some modules of the system may be referred to in various ways according to some embodiments of the present disclosure. However, any number of different modules may be used and operated in a client terminal and/or a server. These modules are intended to be illustrative, not intended to limit the scope of the present disclosure. Different modules may be used in different aspects of the system and method.

According to some embodiments of the present disclosure, flowcharts are used to illustrate the operations performed by the system. It is to be expressly understood, the operations above or below may or may not be implemented in order. Conversely, the operations may be performed in inverted order, or simultaneously. Besides, one or more other operations may be added to the flowcharts, or one or more operations may be omitted from the flowchart.

Technical solutions of the embodiments of the present disclosure are described with reference to the drawings as described below. It is obvious that the described embodiments are not exhaustive and are not limiting. Other embodiments obtained, based on the embodiments set forth in the present disclosure, by those with ordinary skill in the art without any creative works are within the scope of the present disclosure.

In one aspect, the present disclosure is directed to systems and methods for monitoring traffic conditions. The system may determine a time-space diagram based on historical track data of the vehicles that passed a road segment over a period. The system may further determine an intersection spillover time (IST) based on the discharge speed and traffic data of the road. The system may also provide a graphic user interface for presenting the time-space diagram to a user.

FIG. 1 is a schematic diagram illustrating an exemplary system for monitoring traffic conditions according to some embodiments of the present disclosure. For example, the system 100 may be a platform for determining the traffic-signal-cycle patterns of traffic lights to avoid or reduce vehicle spillover based on the track data of the vehicles obtained by the system 100. The system 100 may include a server 110, a driver terminal 120, a storage device130, a network 140, and an information source 150. The server 110 may include a processing engine 112.

In some embodiments, the server 110 may perform a plurality of operations to determine the light-cycle patterns of traffic lights. The traffic-signal-cycle pattern of a traffic light refers to a periodical rule of a plurality of repeated cycles of a traffic light being lit. A cycle of a traffic light may include a green-light period (or duration) and a red-light period (or duration) . The green-light period may be a consistent value, and the red-light period may be a consistent value. The server 110 may control the traffic lights according to the determined traffic-signal-cycle patterns. In some embodiments, the server 110 may obtain the track data of a plurality of vehicles. The server 110 may monitor the traffic condition based on the collected traffic data. In some embodiments, the server 110 may be a single server or a server group. The server group may be centralized, or distributed (e.g., the server 110 may be a distributed system) . In some embodiments, the server 110 may be local or remote. For example, the server 110 may access information and/or data stored in the driver terminal 120, the information source 150, and/or the storage device 130 via the network 140. As another example, the server 110 may be directly connected to the driver terminal 120 and/or the storage device 130 to access stored information and/or data. In some embodiments, the server 110 may be implemented on a cloud platform. Merely by way of example, the cloud platform may include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, an inter-cloud, a multi-cloud, or the like, or any combination thereof. In some embodiments, the server 110 may be implemented on a computing device having one or more components illustrated in FIG. 2 in the present disclosure.

In some embodiments, the server 110 may include a processing engine 112 configured to perform the processes described in the present disclosure. For example, the processing engine 112 may determine a traffic-signal-cycle pattern for monitoring traffic conditions. The processing engine 112 may also determine a time-space diagram based on the historical track data of vehicles. In some embodiments, the processing engine 112 may include one or more processing engines (e.g., single-core processing engine (s) or multi-core processor (s) ) . Merely by way of example, the processing engine 112 may include a central processing unit (CPU) , an application-specific integrated circuit (ASIC) , an application-specific instruction-set processor (ASIP) , a graphics processing unit (GPU) , a physics processing unit (PPU) , a digital signal processor (DSP) , a field programmable gate array (FPGA) , a programmable logic device (PLD) , a controller, a microcontroller unit, a reduced instruction-set computer (RISC) , a microprocessor, or the like, or any combination thereof.

In some embodiments, the driver terminal 120 may transmit positioning information associated with a vehicle to the server 110. For example, the driver terminal 120 may be a smartphone equipped with a global positioning system (GPS) chipset capable of determining the position of the smartphone. The driver terminal 120 may determine its positions over time and transmit the position data (also referred as the track data) to the server 110. The server 110 may treat the position data as the track data of a vehicle associated with the user of the driver terminal 120 since the positions of the driver terminal 120 may be the same (or almost the same) as the positions of the vehicle. As another example, the driver terminal 120 may be a computing device installed in a vehicle and equipped with a GPS chipset. The driver terminal 120 may determine its positions over time and transmit the position data to the server 110. The server 110 may further obtain track data corresponding to the positioning information. For example, the track data may include a plurality of positions of the driver terminal 120 and/or the vehicles.

In some embodiments, the driver terminal 120 may include a mobile device, a tablet computer, a laptop computer, and a built-in device in a motor vehicle, or the like, or any combination thereof. In some embodiments, the mobile device may include a smart home device, a wearable device, a smart mobile device, a virtual reality device, an augmented reality device, or the like, or any combination thereof. In some embodiments, the smart home device may include a smart lighting device, a control device of an intelligent electrical apparatus, a smart monitoring device, a smart television, a smart video camera, an interphone, or the like, or any combination thereof. In some embodiments, the wearable device may include a smart bracelet, a smart footgear, a smart glass, a smart helmet, a smartwatch, a smart clothing, a smart backpack, a smart accessory, or the like, or any combination thereof. In some embodiments, the smart mobile device may include a smartphone, a personal digital assistant (PDA) , a gaming device, a navigation device, or the like, or any combination thereof. In some embodiments, the built-in device in the motor vehicle may include an onboard computer, an onboard television, etc. In some embodiments, the driver terminal 120 may include a device with positioning technology for locating the position of the vehicle (e.g., a device equipped with a GPS chipset) .

The storage device 130 may store data and/or instructions. In some embodiments, the storage device 130 may store data obtained/acquired from the driver terminal 120. In some embodiments, the storage device 130 may store data and/or instructions that the server 110 may execute or use to perform exemplary methods described in the present disclosure. In some embodiments, the storage device 130 may include a mass storage, removable storage, a volatile read-and-write memory, a read-only memory (ROM) , or the like, or any combination thereof. Exemplary mass storage may include a magnetic disk, an optical disk, a solid-state drive, etc. Exemplary removable storage may include a flash drive, a floppy disk, an optical disk, a memory card, a zip disk, a magnetic tape, etc. Exemplary volatile read-and-write memory may include random-access memory (RAM) . Exemplary RAM may include a dynamic RAM (DRAM) , a double date rate synchronous dynamic RAM (DDR SDRAM) , a static RAM (SRAM) , a thyristor RAM (T-RAM) , and a zero-capacitor RAM (Z-RAM) , etc. Exemplary ROM may include a mask ROM (MROM) , a programmable ROM (PROM) , an erasable programmable ROM (PEROM) , an electrically erasable programmable ROM (EEPROM) , a compact disk ROM (CD-ROM) , and a digital versatile disk ROM, etc. In some embodiments, the storage device 130 may be implemented on a cloud platform. Merely by way of example, the cloud platform may include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, an inter-cloud, a multi-cloud, or the like, or any combination thereof.

In some embodiments, the storage device 130 may be connected to the network 140 to communicate with one or more components in the system 100 (e.g., the server 110, the driver terminal 120) . One or more components in the system 100 may access the data or instructions stored in the storage device 130 via the network 140. In some embodiments, the storage device 130 may be directly connected to or communicate with one or more components in the system 100 (e.g., the server 110, the driver terminal 120) . In some embodiments, the storage device 130 may be part of the server 110.

The network 140 may facilitate exchange of information and/or data. In some embodiments, one or more components in the system 100 (e.g., the server 110, the driver terminal 120, the storage device 130) may send and/or receive information and/or data to/from another component (s) in the system 100 via the network 140. For example, the server 110 may obtain/acquire the trajectory data of the vehicles from a terminal via the network 140. In some embodiments, the network 140 may be any type of wired or wireless network, or combination thereof. Merely by way of example, the network 140 may include a cable network, a wireline network, an optical fiber network, a tele communications network, an intranet, an Internet, a local area network (LAN) , a wide area network (WAN) , a wireless local area network (WLAN) , a metropolitan area network (MAN) , a wide area network (WAN) , a public telephone switched network (PSTN) , a Bluetooth ^TM network, a ZigBee ^TM network, a near field communication (NFC) network, a global system for mobile communications (GSM) network, a code-division multiple access (CDMA) network, a time-division multiple access (TDMA) network, a general packet radio service (GPRS) network, an enhanced data rate for GSM evolution (EDGE) network, a wideband code division multiple access (WCDMA) network, a high speed downlink packet access (HSDPA) network, a long term evolution (LTE) network, a user datagram protocol (UDP) network, a transmission control protocol/Internet protocol (TCP/IP) network, a short message service (SMS) network, a wireless application protocol (WAP) network, a ultra wide band (UWB) network, an infrared ray, or the like, or any combination thereof. In some embodiments, the system 100 may include one or more network access points. For example, the system 100 may include wired or wireless network access points such as base stations and/or wireless access points 140-1, 140-2, …, through which one or more components of the system 100 may be connected to the network 140 to exchange data and/or information.

The information source 150 may be a source configured to provide other information for the system 100. The information source 150 may provide the system 100 with service information, such as weather conditions, traffic information, information of laws and regulations, news events, or the like. In some embodiments, the information source 150 may include an official traffic database, which provides historical and/or current traffic data (e.g., a spillover time, traffic light pattern) . The server 110 may obtain the cycle length of a traffic light from the information source 150. The cycle length of a traffic light refers to a periodical duration of the traffic light including a green light duration, a red-light period, and/or a yellow light duration. In the present disclosure, the red-light period and the green-light period are discussed while the yellow-light duration is not discussed, but a person having ordinary skill in the art would understand how to include the yellow-light duration in view of the present disclosure without undue experimentation. In some embodiments, the yellow-light duration may be considered to be included in the green-light period or the red-light period. The information source 150 may be implemented in a single central server, multiple servers connected via a communication link, or multiple personal devices. When the information source 150 is implemented in multiple personal devices, the personal devices can generate content (e.g., as referred to as the “user-generated content” ) , for example, by uploading text, voice, image, and video to a cloud server. An information source may be generated by the multiple personal devices and the cloud server.

FIG. 2 is a schematic diagram illustrating exemplary components of a computing device according to some embodiments of the present disclosure. The server 110, the driver terminal 120, and/or the storage device 130 may be implemented on the computing device 200 according to some embodiments of the present disclosure. The particular system may use a functional block diagram to explain the hardware platform containing one or more user interfaces. The computer may be a computer with general or specific functions. Both types of the computers may be configured to implement any particular system according to some embodiments of the present disclosure. Computing device 200 may be configured to implement any components that perform one or more functions disclosed in the present disclosure. For example, the computing device 200 may implement any component of the system 100 as described herein. In FIGs. 1 and 2, only one such computer device is shown purely for convenience purposes. One of ordinary skill in the art would understand at the time of filing of this application that the computer functions relating to the service as described herein may be implemented in a distributed fashion on a number of similar platforms, to distribute the processing load.

The computing device 200, for example, may include COM ports 250 connected to and from a network connected thereto to facilitate data communications. The computing device 200 may also include a processor (e.g., the processor 220) , in the form of one or more processors (e.g., logic circuits) , for executing program instructions. For example, the processor 220 may include interface circuits and processing circuits therein. The interface circuits may be configured to receive electronic signals from a bus 210, wherein the electronic signals encode structured data and/or instructions for the processing circuits to process. The processing circuits may conduct logic calculations, and then determine a conclusion, a result, and/or an instruction encoded as electronic signals. Then the interface circuits may send out the electronic signals from the processing circuits via the bus 210.

The exemplary computing device may include the internal communication bus 210, program storage and data storage of different forms including, for example, a disk 270, and a read-only memory (ROM) 230, or a random access memory (RAM) 240, for various data files to be processed and/or transmitted by the computing device. The exemplary computing device may also include program instructions stored in the ROM 230, RAM 240, and/or another type of non-transitory storage medium to be executed by the processor 220. The methods and/or processes of the present disclosure may be implemented as the program instructions. The computing device 200 also includes an I/O component 260, supporting input/output between the computer and other components. The computing device 200 may also receive programming and data via network communications.

Merely for illustration, only one CPU and/or processor is illustrated in FIG. 2. Multiple CPUs and/or processors are also contemplated; thus, operations and/or method steps performed by one CPU and/or processor as described in the present disclosure may also be jointly or separately performed by the multiple CPUs and/or processors. For example, if in the present disclosure the CPU and/or processor of the computing device 200 executes both step A and step B, it should be understood that step A and step B may also be performed by two different CPUs and/or processors jointly or separately in the computing device 200 (e.g., the first processor executes step A and the second processor executes step B, or the first and second processors jointly execute steps A and B) .

FIG. 3 is a block diagram illustrating exemplary hardware and/or software components of an exemplary mobile device according to some embodiments of the present disclosure. The driver terminal 120 may be implemented on the mobile device 300 according to some embodiments of the present disclosure. As illustrated in FIG. 3, the mobile device 300 may include a communication module 310, a display 320, a graphics processing unit (GPU) 330, a central processing unit (CPU) 340, an I/O 350, a memory 360, and a storage 390. The CPU 340 may include interface circuits and processing circuits similar to the processor 220. In some embodiments, any other suitable component, including but not limited to a system bus or a controller (not shown) , may also be included in the mobile device 300. In some embodiments, a mobile operating system 370 (e.g., iOS ^TM, Android ^TM, Windows Phone ^TM) and one or more applications 380 may be loaded into the memory 360 from the storage 390 in order to be executed by the CPU 340. The applications 380 may include a browser or any other suitable mobile apps for transmitting the trajectory data to the server 110. User interaction with the information stream may be achieved via the I/O devices 350 and provided to the processing engine 112 and/or other components of the system 100 via the network 140.

In order to implement various modules, units and their functions described above, a computer hardware platform may be used as hardware platforms of one or more elements (e.g., a component of the server 110 described in FIG. 1) . Since these hardware elements, operating systems, and program languages are common, it may be assumed that persons skilled in the art may be familiar with these techniques and they may be able to provide information required in the traffic lights controlling according to the techniques described in the present disclosure. A computer with user interface may be used as a personal computer (PC) , or other types of workstations or terminal devices. After being properly programmed, a computer with user interface may be used as a server. It may be considered that those skilled in the art may also be familiar with such structures, programs, or general operations of this type of computer device. Thus, extra explanations are not described for the figures.

FIG. 4 is a block diagram illustrating an exemplary processing engine 112 according to some embodiments of the present disclosure. The processing engine 112 may include an acquisition module 410, a determining module 420, and a graphic user interface (GUI) generation module 430.

The acquisition module 410 may obtain historical track data of a plurality of vehicles that passed a road (or a road segment) , an upstream intersection, and a downstream intersection over a period. In some embodiments, a positioning device (e.g., a smartphone equipped with a GPS chipset) associated with at least one of the plurality of vehicles may transmit the track data to the storage device 130 via the network 140. In some embodiments, the positioning device may be integrated into a user terminal (e.g., the driver terminal 120) . The user terminal may transmit the track data to the storage device 130. The acquisition module 410 may further obtain historical track data of the plurality of vehicles over a period. The historical track data may include spatial information and time information associated with the plurality of vehicles. The time information may include corresponding the time points when the plurality of vehicles are at these positions. The time information may also include traffic light data of an intersection (e.g., a green-light period, a red-light period) , etc. The historical period may include a predetermined period, for example, an hour, a day, a week, a month, etc. The acquisition module 410 may process the historical track data based on the spatial information and time information associated with the plurality of vehicles. For example, the processing engine 112 may determine a space-time diagram using the spatial information and time information.

The acquisition module 410 may obtain the cycle pattern of a first traffic light and the cycle pattern of a second traffic light. The acquisition module 410 may obtain the cycle pattern of a traffic light via the information source 150. The first traffic light may be located at the downstream intersection. The second traffic light may be located at the upstream intersection. The cycle pattern of a traffic light refers to a periodical duration of the traffic light including a green-light period, a red-light period, and/or a yellow-light duration. In the present disclosure, the red-light period and the green-light period are discussed while the yellow-light duration is not discussed, but a person having ordinary skill in the art would understand how to include the yellow-light duration in view of the present disclosure without undue experimentation. In some embodiments, the yellow-light duration may be considered to be included in the green-light period or the red-light period.

The determination module 420 may process the historical track data of the plurality of vehicles to generate a time-space diagram as illustrated in FIG. 6A. Alternatively or additionally, the determination module 420 may process the historical track data of the plurality of vehicles to generate a time- space diagram as illustrated in FIG. 6B. In some embodiments, the time-space diagram illustrated in FIG. 6B may include one or more sections. The time-space diagram as illustrated in FIG. 6B may be generated based on the one or more sections. The one or more section may fall into three categories, which may include a first section, a second section, and a third section.

The determination module 420 may further include a first section determination unit 421, a second section determination unit 422, and a third section determination unit 423. The first section determination unit 421 may determine the first section of the time-space diagram based on a free-flow speed of the road segment. The first section may correspond to a stage in which the queue length increases. As illustrated in FIG. 6B, the queue length trajectory may increase if vehicles from the upstream join the queue (e.g., Stages (2) , (4) , and (9) as shown in FIG. 6B) . A vector representing the first section may indicate a growth of the queue length over a period. A slope of the vector representing the first section may equal to the free-flow speed of the road segment. Detailed descriptions related to the free-flow speed may be found elsewhere in this disclosure (e.g., FIG. 5B and the descriptions thereof) .

The second section determination unit 422 may determine the second section of the time-space diagram based on a back-propagation wave speed of the road segment. The second section may correspond to a stage in which the queue length decreases. As illustrate in FIG. 6B, the queue length trajectory may decrease if vehicles pass through the road segment via the downstream intersection (e.g., Stage (6) , and (11) as shown in FIG. 6B) . A slope of a vector representing the second section may equal to the back-propagation wave speed of the road segment. Detailed descriptions related to the back-propagation wave speed may be found elsewhere in this disclosure (e.g., FIG. 5B and the descriptions thereof) .

The third section determination unit 423 may determine the third section of the time-space diagram based on a position of the last vehicle in the queue. The third section may correspond to a stage in which the queue length remains unchanged if no vehicle comes from the upstream (e.g., Stage (1) , (3) , (5) , and (10) as shown in FIG. 6B) . The third section determination unit 423 may determine a last vehicle in the queue based on the historical track data of the plurality of vehicles, the third section based on a position of the last vehicle in the queue.

The GUI generation module 430 may generate a graphic user interface for providing the time-space diagram to the user. The GUI generation module 430 may generate the graphical user interface, and display the graphic user interface via a physical display (e.g., a display of a generic computer, a display of a mobile device, etc. ) The time-space diagram (e.g., the time-space diagram 610 or the time-space diagram 620) may be displayed in the graphic user interface. Detailed descriptions related to the graphic user interface may be found elsewhere in this disclosure (e.g., FIG. 9 and the descriptions thereof) .

It should be noted that the descriptions above in relation to the processing engine 112 are provided for the purposes of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, various variations and modifications may be conducted under the guidance of the present disclosure. However, those variations and modifications do not depart the scope of the present disclosure. For example, the processing engine 112 may further include a storage module (not shown in FIG. 4) . The storage module may be configured to store data generated during any process performed by any component of in the processing engine 112. As another example, each of components of the processing engine 112 may associate with a storage module. Additionally or alternatively, the components of the processing engine 112 may share a common storage module. Similar modifications should fall within the scope of the present disclosure.

FIG. 5A is a schematic diagram illustrating an exemplary one-way road network according to some embodiments of the present disclosure. FIG. 5A is a simplified one-way road network including an upstream intersection 504 (i.e., the intersection A) and a downstream intersection 506 (i.e., the intersection B) connected by a road segment 502. In some embodiments, the turning movements of vehicles in the one-way road network 500 may be forbidden. In some embodiments, when the traffic condition is gridlock at a period on the road segment 502, a plurality of vehicles in the queue may be stopped to wait on the road segment 502 to pass the downstream intersection 506. If the queue cannot be fully discharged within a cycle of a traffic light at the downstream intersection 506, a residual queue may be formed and even spill to the upstream intersection 504, which may cause the gridlock of the upstream intersection 504. On the other hand, a gridlock may begin with queue spillover on one road segment (or link) and then spread to the adjacent road segment (or link) . If the queue spillover is reduced or controlled, the gridlock may be prevented. More descriptions about the queue spillover may be found elsewhere in the present disclosure (e.g., FIG. 6, 6C-6D, and 6E-6F, and the descriptions thereof) .

It should be noted that the above description is merely provided for the purposes of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, multiple variations and modifications may be made under the teachings of the present disclosure. For example, the one-way road network 500 may include but not limited that two intersections, such as three intersections.

FIG. 5B illustrates a diagram illustrating exemplary relationships between a traffic flow rate of a road segment and a traffic density of the road segment. The term “traffic flow rate” (or “vehicle flow rate” ) of a road segment used in the present disclosure refers to a rate at which vehicles pass a fixed point of the road segment. The term “traffic density” (or “vehicle density” ) of the road segment used in the present disclosure refers to a count of vehicles over a stretch of the road segment. Both the traffic flow rate and traffic density of the road segment may be determined based on traffic data of the road segment collected. For instance, traffic flow rate and traffic density of the road segment may be determined based on a moving observer technique. The traffic data may include a count of vehicles passing the fixed point of the road segment or the velocity of a vehicle passing the fixed point of the road segment. The traffic data may be collected based on a manual counting technique, which may include assigning a person to record traffic as it passes. Alternatively or additionally, traffic data may be collected based on an automatic counting technique, which may include installing a detector on the fixed point of the road segment to record traffic as it passes. Exemplary detector for traffic data collection may include but not limited to pneumatic tubes, inductive loops, weigh-in-motion sensors, radar detectors, video cameras, or the like, or any combination thereof.

As shown in FIG. 5B, several statuses of a road segment may arise, including but not limited to, free-flowing status, saturated status, and capacity status. In the free-flowing status, represented by a first vector from 510 pointing to 520 as shown in FIG. 5B, the traffic density is low enough (inferior to the critical density k _c as shown in FIG. 5B) that vehicles are not impeded by each other and travel at a free-flow speed v, represented by a slope of the first vector as shown in FIG. 5B. In some embodiments, the free-flow speed v may be related to a speed limit of the road segment regulated by the law. In the saturated status, the traffic density is at the maximum and set at jam density k _j, as shown in FIG. 5B. Vehicles may no longer travel and wait in a queue. In the capacity status, represented by a second vector from 520 pointing to 530 as shown in FIG. 5B, the traffic density is between k _c and k _j. As a result, vehicles may impede each other and reduce their speed accordingly. A slope of the second vector may be related to a back-propagation wave speed w. The back-propagation wave speed w may be determined based on Equation (1) as follows:

where q _c and ρ _c denote a traffic flow rate and a traffic density for the capacity status, respectively; and q _j and ρ _j denote a traffic flow rate and a traffic density for the saturated status, respectively.

FIG. 6A is a schematic diagram illustrating exemplary time-space diagram according to some embodiments of the present disclosure. The processing engine 112 may determine the time-space diagram based on the historical track data of the plurality of vehicles. As shown in FIG. 6A, the time-space diagram may include a bar 611 (i.e., the first graphic representation) indicating the cycle pattern of the first traffic light and a bar 612 (i.e., the second graphic representation) indicating the cycle pattern of the second traffic light. The horizontal axis of the time-space diagram denotes the time, which is represented by t. The vertical axis of the time-space diagram denotes the position of a vehicle, which is represented by l. For example, l ₀ denotes the position of the upstream intersection, and l ₁ denotes the position of the downstream intersection. The distance between the upstream intersection and the downstream intersection is denoted by L. Dashed line 613 (i.e., the third graphic representation) denotes a historical trajectory line of a vehicle, which is determined based on its historical track data.

In some embodiments, an intersection spillover time may be determined based on the time-space diagram as shown in FIG. 6A. For example, as shown in FIG. 6A, the time-space diagram may include the historical trajectories of a plurality of vehicles at a plurality of cycles of the traffic lights. Each line represents the track of a vehicle over time. A cycle may include a green-light period and a red-light period. If a portion of a trajectory line is flat in the time-space diagram (e.g.,

sections

614, 615, 616, and 617 as shown in FIG. 6A) , the corresponding vehicle is considered to be still over the period corresponding to the flat portion of the trajectory line. A position corresponding to the flat portion of the trajectory line may be designated as a stop position. If the stop position of the last queued vehicle is beyond the stop line of the upstream intersection (e.g.,

sections

614 and 615 shown in FIG. 6A) , the period corresponding to the flat portion of the trajectory line may be considered as an intersection spillover time. The intersection spillover time (IST) refers to a duration that the queue length trajectory blocks the upstream intersection. In some embodiments, the IST may include two distinct parts, namely, a backward intersection spillover time (BIST) and a perpendicular intersection spillover time (PIST) . The BIST may also be referred to as a green-light spillover duration in the present disclosure. The PIST may also be referred to as a red-light spillover duration in the present disclosure. It should be understood that once a spillover takes place on the road segment, the spillover may spread backward along the road segment, which means vehicles from the upstream cannot enter the road near the end of the green-light period. Thus, a backward intersection spillover time (BIST) that the queue length trajectory impedes upstream traffic entering the link may arise in this situation. In addition, the spillover may spread perpendicular to the road, which means the vehicles from the cross street cannot pass the intersection at the beginning of their green-light period (which is the red-light period for the described road) . Thus, a perpendicular intersection spillover time (PIST) that the queue length trajectory blocks traffic from the cross street may arise in this situation.

FIG. 6B is a schematic diagram illustrating exemplary an exemplary time-space diagram according to some embodiments of the present disclosure. FIG. 6B shows an example how a queue length trajectory (i.e., the position of the last queued vehicle in a road segment) moves in a time-space diagram. The queue length trajectory refers to a path of the last queued vehicle in a road segment. The horizontal axis of the time-space diagram is time, and the vertical axis of the time-space diagram is the position of the last queued vehicle at a time point. A traffic light may be at a downstream intersection (which is also referred herein as the first traffic light) , and a traffic light may be at an upstream intersection (which is also referred herein as the second traffic light) . The downstream intersection (e.g., the downstream intersection 506 shown in FIG. 5A) and the upstream intersection (e.g., the upstream intersection 504 shown in FIG. 5A) may be connected by the road segment (e.g., the road segment 502 shown in FIG. 5A) . L denotes the length of the road segment, which is the distance from the upstream intersection to downstream intersection. z denotes the length of the upstream intersection. Two groups of parallel auxiliary lines, for example, the dashed

auxiliary lines

601, 603, 605 and the dashed

auxiliary lines

602, 604, 606 may be depicted to help the determination of the queue length. One group including the dashed

auxiliary lines

601, 603, and 605 may start from a phase switch time of an upstream traffic signal and move toward the bottom right at a free-flow speed v. The other group including the dashed

auxiliary lines

602, 604, and 606 may start from a phase switch time of a downstream signal and move towards top right at a back-propagate speed w. The queue length trajectory may be shown by a plurality of bold solid lines that consist of many stages such as Stage (1) , Stage (2) , …, and so on.

The queue length trajectory may increase if vehicles from the upstream join the queue (e.g., Stage (4) as shown in FIG. 6B) , and the queue length trajectory may remain unchanged if no vehicle comes from the upstream (e.g., Stage (5) as shown in FIG. 6B) . The decreasing lines (e.g., the bold dashed lines shown in Stage (6) in FIG. 6B) may represent the positions of the last vehicle of the queue during discharging. In some embodiments, the initial condition at time t=t ₀ may be assumed as that a queue with n ₀ vehicles (i.e., the number of the vehicles equal to n ₀) accumulates on the road. The initial queue length l ₀ may be given by l ₀=n ₀×ρ _j. Due to a relatively large initial value of l ₀, the initial queue may be not able to be dissolved in a first cycle but may be dissolved in a second cycle. In this case, l ₀ may satisfy the following inequality (2) :

l _r+l _g<l ₀+l _g≤2 (l _r+l _g) (2) ,

where l _g denotes a first growth parameter of the queue related to a green-light period, and l _r denotes a second growth parameter of the queue related to a red-light period. The first growth parameter may correspond to the growth of the queue length in one green light period, and the second growth parameter may correspond to the growth of the queue length in one red light period. As illustrated in FIG. 6B, the first growth parameter may be determined based on a triangle formed by auxiliary lines 603, 604 and the horizontal axis including a green-light cycle length. The second growth parameter may be determined based on a triangle formed by auxiliary lines 605, 606 and the horizontal axis including a red-light cycle length. The slope of the auxiliary line 603 or 605 may be the free-flow speed v, and the slope of the auxiliary line 604 or 606 may be the back-propagation wave speed w. In some embodiments, l _g may be given by Equation (3) as follows:

where g ₀ denotes a green-light period, and l _r may be given by Equation (4) as follows:

where c denotes a cycle of a traffic light including a green-light period and a red-light period.

The queue length trajectory may finally converge to a cyclic recurrent pattern shown by a combination of stages (7) to (10) in FIG. 6B. A maximum queue length l ^max for this case may be given by Equation (5) as follows:

l ^max=l ₀+2l _g (5) .

In this case, T ^max denotes the duration that the maximum queue length l ^max lasts. Equation (6) may be determined based on the similarity of triangles, as follows:

Then, the value of T ^max may be determined by Equation (7) as follows:

In some embodiments, given different initial values of l ₀, the processing engine 112 may determine a general expression of l ^max and T ^max as follows:

where function ceil (x) rounds x to the nearest integer towards infinity, function floor (x) rounds x to a nearest integer towards minus infinity, and function mod (x, y) refers to a reminder after dividing x by y.

FIG. 6C is a schematic diagram illustrating exemplary queue length trajectories in spillover on one road segment according to some embodiments of the present disclosure. FIG. 6C is a time-space diagram. As shown in FIG. 6C, L denotes the length of the road segment, which is the distance from the upstream intersection to downstream intersection. z denotes the length of the upstream intersection. The first traffic light is at the downstream intersection. The second traffic light is at the upstream intersection.

An actual queue length trajectory on the road segment is bold black lines that consist of many stages in FIG. 6C, while a reference trajectory 631 (i.e., an initial trajectory shown in FIG. 6C) in the first case is also depicted for comparison. At time t=t _s, the queue length trajectory reaches the stop-line of the upstream intersection and the queue spills to the upstream and fully blocks the upstream intersection. The actual maximum queue length (i.e., l _max) that is equal to the length of the road segment (i.e., L) is held until the back-propagation wave from the downstream intersection reaches the upstream intersection when a traffic light has already turned to red. The queue length trajectory may be shown by a plurality of bold black lines that consist of many stages in FIG. 6C. An initial trajectory may be represented by 631. A partial time-space diagram that includes a spillover may be represented by 632. An enlarge time-space diagram about the partial time-space diagram 632 may be shown in FIG. 6D.

A whole intersection spillover time (IST) refers to a duration that the queue length trajectory blocks the upstream intersection. In some embodiments, the whole intersection spillover time (IST) may include two distinct parts, namely, a backward intersection spillover time (BIST) and a perpendicular intersection spillover time (PIST) . The BIST may also be referred to as a green-light spillover duration in the present disclosure. The PIST may also be referred to as a red-light spillover duration in the present disclosure. It should be understood that once spillover takes place on the road segment, the spillover may spread backward along the road segment, which means vehicles from the upstream cannot enter the road near the end of the green light duration. Thus, a backward intersection spillover time (BIST) that the queue length trajectory impedes upstream traffic entering the link may arise in this situation. In addition, the spillover may spread perpendicular to the road, which means vehicles from the cross street cannot pass the intersection at the beginning of their green-light period (which is red-light period for the described road) . Thus, a perpendicular intersection spillover time (PIST) that the queue length trajectory blocks traffic from the cross street may arise in this situation. The spillover part of the time-space diagram may be denoted by a dashed box 632. In some embodiments, the whole intersection spillover time may be described by Equation (1) as follows:

IST=BIST+PIST (10) .

FIG. 6D shows an enlarged view of the box 632 (i.e., spillover portion) in FIG. 6C. As shown in FIG. 6D, the box ACDE may be a parallelogram. Consequently, the IST (indicated by a length of AC in FIG. 6D) may equal to T ^max, which may be indicated by the length of DE in FIG. 6D determined by Equation (11) as follows:

In this case, the length of AB represents BIST, and the length of BC represents PIST. According to the similarity of triangles EAB, XCB and XDE, BIST and PIST may be determined according to Equation (12) and Equation (13) , respectively, as follows:

where X is the nearest crossover point to the upstream intersection that is on both the upstream red wave and downstream green wave simultaneously. A value of l ^max and a vale of T ^max are given in Equations (8) and (9) , and the position of X may be determined according to Equation (14) as follows:

In some embodiments, the BIST may be equal to zero, and the IST may equal to the PIST. For instance, the dashed circle 643 as shown in FIG. 6D. PIST may be equal to the length of B’ C’ .

Nevertheless, the case as illustrated in FIG. 6C and FIG. 6D is not the only case. In some embodiments, the crossover point X is beyond the link length, as shown in FIG. 6E and FIG. 6F. FIG. 6E is a schematic diagram illustrating exemplary queue length trajectories in a spillover on one road according to some embodiments of the present disclosure, and FIG. 6F is an enlarged view of the spillover part 652 in FIG. 6E.

The case as illustrated in FIG. 6E and FIG. 6F may occur when the discharge wave starting from the downstream intersection reaches the upstream stop line during its green-light time. In the second case, a queue that stops at the upstream intersection may be able to be dissolved at the same green duration in which the queue reaches the upstream intersection. As a consequence, no PIST arises, and the perpendicular side street is not affected. For FIG. 6E, the expressions of BIST and PIST may be derived directly from Equations (15) and (16) as follows:

BIST=T ^max (15) ,

PIST=0 (16) .

FIG. 7 is a flowchart illustrating an exemplary process for presenting traffic information of a road segment to a user according to some embodiments of the present disclosure. The process 700 may be executed by the system 100. For example, the process 700 may be implemented as a set of instructions (e.g., an application) stored in the storage device 130. The processing engine 112 may execute the set of instructions and, when executing the instructions, it may be configured to perform the process 700. The operations of the illustrated process presented below are intended to be illustrative. In some embodiments, the process 700 may be accomplished with one or more additional operations not described and/or without one or more of the operations discussed. Additionally, the order in which the operations of the process as illustrated in FIG. 7 and described below is not intended to be limiting.

In 702, the processor (e.g., the acquisition module 410 of the processing engine 112) may obtain historical track data of a plurality of vehicles that passed a road, an upstream intersection, and a downstream intersection over a period. The upstream intersection and the downstream intersection may be at two ends of the road segment. For example, as shown in FIG. 5A, upstream intersection A and downstream intersection B are at two ends of road segment 502. The plurality of vehicles may flow from upstream intersection A to downstream intersection B along road segment 502. In some embodiments, a positioning device (e.g., a smartphone equipped with a GPS chipset) associated with at least one of the plurality of vehicles may transmit the track data to the storage device 130 via the network 140. In some embodiments, the positioning device may be integrated into a user terminal (e.g., the driver terminal 120) . The user terminal may transmit the track data to the storage device 130. The acquisition module 410 may further obtain historical track data of the plurality of vehicles over a period. The historical track data may include spatial information and time information associated with the plurality of vehicles. For example, the spatial information may include positions of the plurality of vehicles traveling on the road segment 502. The time information may include corresponding the time points when the plurality of vehicles are at these positions. The time information may also include traffic light data of an intersection (e.g., a green light duration, a red-light period) , etc. The historical period may include a predetermined period, for example, an hour, a day, a week, a month, etc. The processor (e.g., the acquisition module 410 of the processing engine 112) may process the historical track data based on the spatial information and time information associated with the plurality of vehicles. For example, the processing engine 112 may determine a space-time diagram using the spatial information and time information.

In 704, the processor (e.g., the acquisition module 410 of the processing engine 112) may obtain the cycle pattern of a first traffic light and the cycle pattern of a second traffic light. In some embodiments, the processor (e.g., the acquisition module 410 of the processing engine 112) may obtain the cycle pattern of a traffic light via the information source 150. The first traffic light may be located at the downstream intersection. The second traffic light may be located at the upstream intersection. The cycle pattern of a traffic light refers to a periodical duration of the traffic light including a green-light period, a red-light period, and/or a yellow-light duration. In the present disclosure, the red-light period and the green-light period are discussed while the yellow-light duration is not discussed, but a person having ordinary skill in the art would understand how to include the yellow-light duration in view of the present disclosure without undue experimentation. In some embodiments, the yellow-light duration may be considered to be included in the green-light period or the red-light period.

In 706, the processor (e.g., the determination module 420 of the processing engine 112) may determine and generate a time-space diagram related to the road segment based on the historical track data of a plurality of vehicles, the cycle pattern of the first traffic light, and the cycle pattern of the second traffic light. In some embodiments, the time-space diagram includes a first graphic representation indicating to the cycle pattern of the first traffic light, a second graphic representation indicating to the cycle pattern of the second traffic light, and a third graphic representation indicating a length of a queue on the road segment formed by one or more vehicles of the plurality of vehicles.

In some embodiments, the processor (e.g., the determination module 420 of the processing engine 112) may process the historical track data of the plurality of vehicles to generate a time-space diagram as illustrated in FIG. 6A. FIG. 6A is a schematic diagram illustrating exemplary time-space diagram 610 according to some embodiments of the present disclosure. The processor (e.g., the determination module 420 of the processing engine 112) may determine the time-space diagram based on the historical track data of the plurality of vehicles. As shown in FIG. 6A, the time-space diagram may include a bar 611 (i.e., the first graphic representation) indicating the cycle pattern of the first traffic light, a bar 612 (i.e., the second graphic representation) indicating the cycle pattern of the second traffic light. The horizontal axis of the time-space diagram is time, which is represented by t. The vertical axis of the time-space diagram is the position of a vehicle, which is represented by l. For example, l ₀ denotes the position of the upstream intersection, and l ₁ denotes the position of the downstream intersection. The distance between the upstream intersection and the downstream intersection is denoted by L. Dashed line 613 (i.e., the third graphic representation) denotes a historical trajectory line of a vehicle, which is determined based on its historical track data. The processing engine 112 may convert the historical track data of the plurality of vehicles into corresponding trajectory lines. Detailed descriptions related to time-space diagram 610 may be found elsewhere in this disclosure (e.g., FIG. 6A and the descriptions thereof) .

Alternatively or additionally, the processor (e.g., the determination module 420 of the processing engine 112) may process the historical track data of the plurality of vehicles to generate a time-space diagram as illustrated in FIG. 6B. FIG. 6B shows an exemplary time-space diagram 620 illustrating a queue length trajectory (i.e., the position of the last queued vehicle in a road segment) moves in a time-space diagram. The queue length trajectory refers to a path of the last queued vehicle in a road segment. The horizontal axis of the time-space diagram may represent time, and the vertical axis of the time-space diagram may represent a position of the last queued vehicle at a time point. The time-space diagram 620 may include a bar 621 (i.e., the first graphic representation) indicating the cycle pattern of the first traffic light, a bar 622 (i.e., the second graphic representation) indicating the cycle pattern of the second traffic light. The time-space diagram 620 may further include a curve 623 (i.e., the third graphic representation) indicating the length of the queue on the road segment formed by the one or more vehicles of the plurality of vehicles. Detailed descriptions related to time-space diagram 620 may be found elsewhere in this disclosure (e.g., FIG. 6B and the descriptions thereof) .

In some embodiments, the time-space diagram illustrated in FIG. 6B may include one or more sections. The time-space diagram as illustrated in FIG. 6B may be generated based on the one or more sections. The one or more section may fall into three categories, which may include a first section, a second section, and a third section. Detailed descriptions related to the three categories of the one or more sections may be found elsewhere in this disclosure (e.g., FIG. 8 and the descriptions thereof) .

In 708, the processor (e.g., the GUI generation module 430 of the processing engine 112) may generate a graphic user interface for providing the time-space diagram to the user. The time-space diagram (e.g., the time-space diagram 610 or the time-space diagram 620) may be displayed in the graphic user interface. Detailed descriptions related to the graphic user interface may be found elsewhere in this disclosure (e.g., FIG. 9 and the descriptions thereof) .

It should be noted that the above description of the process for presenting traffic information of a road segment to a user is provided for the purpose of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, modules may be combined in various ways, or connected with other modules as sub-systems. Various variations and modifications may be conducted under the teaching of the present disclosure. However, those variations and modifications may not depart from the spirit and scope of this disclosure.

FIG. 8 is a flowchart illustrating an exemplary process for generating a time-space diagram according to some embodiments of the present disclosure. The process 800 may be executed by the system 100. For example, the process 800 may be implemented as a set of instructions (e.g., an application) stored in the storage device 130. The processing engine 112 may execute the set of instructions and, when executing the instructions, it may be configured to perform the process 800. The operations of the illustrated process presented below are intended to be illustrative. In some embodiments, the process 800 may be accomplished with one or more additional operations not described and/or without one or more of the operations discussed. Additionally, the order in which the operations of the process as illustrated in FIG. 8 and described below is not intended to be limiting.

In 802, the processor (e.g., the determination module 420 or the first section determination unit 421 of the processing engine 112) may determine a first section of the time-space diagram based on a free-flow speed of the road segment. The first section may correspond to a stage in which the queue length increases. As illustrated in FIG. 6B, the queue length trajectory may increase if vehicles from the upstream join the queue (e.g., Stage (2) , (4) , and (9) as shown in FIG. 6B) . A vector representing the first section may indicate the growth of the queue length over a period. The slope of the vector representing the first section may equal to the free-flow speed of the road segment. Detailed descriptions related to the free-flow speed may be found elsewhere in this disclosure (e.g., FIG. 5B and the descriptions thereof) . The processor (e.g., the determination module 420 or the first section determination unit 421 of the processing engine 112) may determine the free-flow speed of the road segment based on the historical track data of the plurality of vehicles, then determine the first section based on the free-flow speed of the road segment.

In 804, the processor (e.g., the determination module 420 or the second section determination unit 422 of the processing engine 112) may determine a second section of the time-space diagram based on a back- propagation wave speed of the road segment. The second section may correspond to a stage in which the queue length decreases. As illustrate in FIG. 6B, the queue length trajectory may decrease if vehicles pass through the road segment via the downstream intersection (e.g., Stage (6) , and (11) as shown in FIG. 6B) . The slope of a vector representing the second section may equal to the back-propagation wave speed of the road segment. Detailed descriptions related to the back-propagation wave speed may be found elsewhere in this disclosure (e.g., FIG. 5B and the descriptions thereof) . The processor (e.g., the determination module 420 or the second section determination unit 422 of the processing engine 112) may determine back-propagation wave speed of the road segment based on the historical track data of the plurality of vehicles, then determine the second section based on the back-propagation wave speed of the road segment.

In 806, the processor (e.g., the determination module 420 or the third section determination unit 423 of the processing engine 112) may determine a third section of the time-space diagram based on the position of the last vehicle in the queue. The third section may correspond to a stage in which the queue length remains unchanged if no vehicle comes from the upstream (e.g., Stage (1) , (3) , (5) , and (10) as shown in FIG. 6B) . The processor (e.g., the determination module 420 or the third section determination unit 423 of the processing engine 112) may determine a last vehicle in the queue based on the historical track data of the plurality of vehicles, the third section based on a position of the last vehicle in the queue.

It should be noted that the above description of the process for generating a time-space diagram is provided for the purpose of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, modules may be combined in various ways, or connected with other modules as sub-systems. Various variations and modifications may be conducted under the teaching of the present disclosure. However, those variations and modifications may not depart from the spirit and scope of this disclosure.

FIG. 9 is a schematic diagram illustrating exemplary a graphic user interface for providing the time-space diagram to the user. Specifically, FIG. 9 is a schematic diagram illustrating exemplary a graphic user interface for providing the time-space diagram as illustrated in FIG. 6B. The GUI generation module 430 may generate the graphical user interface, which may be displayed in a physical display (e.g., a display of a computer, a display of a mobile device, etc. ) As illustrated in FIG. 9, the graphic user interface, for providing the time-space diagram to the user, may include a road selection field 902, a time period selection field 904, a traffic light selection field 906, and a time-space diagram display field 908. The user may input any character string, related to a certain road or street (e.g., “Summit St. ” , “Graham Ave. ” , etc. ) , into the road selection field 902 to obtain a time-space diagram of that certain street. The user may input any characters string, related to any two traffic lights of that certain road or street (e.g., “2, ” which represents the second traffic light from a certain origin on the road, and “3, ” which represents the third traffic light from the certain origin on the road, etc. ) , into the traffic light selection field 906 to obtain a time-space diagram of a road segment, of that certain road or street, formed by the two certain traffic lights as illustrated in FIG. 5A. The user may input any character string, related to a certain time period (e.g., “5: 00 PM” , “21: 51” , etc. ) , in the time period selection field 904, to obtain a time-space diagram of that certain time period. The GUI generation module 430 may generate and display a time-space diagram in the time-space diagram display field 908, based on the character string input by the user in the road selection field 902, the time period selection field 904, or the traffic light selection field 906.

In some embodiments, the GUI generation module 430 may determine whether some part of the time-space diagram (e.g., the third section as illustrated in FIG. 6B and FIG. 8) reaches or touches the first graphic representation or the second graphic representation of the time-space diagram. If some part of the time-space diagram (e.g., the third section as illustrated in FIG. 6B and FIG. 8) reaches or touch the first graphic representation or the second graphic representation of the time-space diagram, a spillover may exist around the first traffic light represented by the first graphic representation or the second light represented by the second graphic representation. For example, as illustrated in FIGs. 6C and 6D, at time t=t _s, the queue length trajectory reaches the stop-line of the upstream intersection, and the third section AC touches the first graphic representation (i.e., the bar representing the cycle pattern of the first traffic light) . The queue spills to the upstream and fully blocks the upstream intersection. After the GUI generation module 430 determines some part of the time-space diagram (e.g., the third section as illustrated in FIG. 6B and FIG. 8) reaches or touches the first graphic representation or the second graphic representation of the time-space diagram, the GUI generation module 430 may display a visual representation relating to the third section. For example, as illustrated in FIG. 9, when the GUI generation module 430 determines that the third section 910 touches the first graphic representation, the GUI generation module 430 may display an information box 914 near a location where the third section 910 of the time-space diagram touches the first graphic representation. When the GUI generation module 430 determines that the third section 912 reaches or touches the first graphic representation, the GUI generation module 430 may display an information box 916 near a location where the third section 912 of the time-space diagram touches the first graphic representation. In some embodiments, the processor (e.g., the determination module 420 or the third section determination unit 423 of the processing engine 112) may determine the duration of the queue based on a length of the third section, and the visual representation may include an indicator indicating the duration of the queue. For example, as shown in FIG. 9, the processor (e.g., the determination module 420 or the third section determination unit 423 of the processing engine 112) may determine an IST related to the third section 910 based on the length of the third section 901, and the information box 914 generate by the processor (e.g., the GUI generation module 430) may include information of the IST.

It should be noted that the above description of the process for determining a green-light spillover duration and/or a red-light spillover duration is provided for the purpose of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, modules may be combined in various ways, or connected with other modules as sub-systems. Various variations and modifications may be conducted under the teaching of the present disclosure. However, those variations and modifications may not depart from the spirit and scope of this disclosure.

To implement various modules, units, and their functionalities described in the present disclosure, computer hardware platforms may be used as the hardware platform (s) for one or more of the elements described herein. A computer with user interface elements may be used to implement a personal computer (PC) or any other type of work station or terminal device. A computer may also act as a server if appropriately programmed.

Having thus described the basic concepts, it may be rather apparent to those skilled in the art after reading this detailed disclosure that the foregoing detailed disclosure is intended to be presented by way of example only and is not limiting. Various alterations, improvements, and modifications may occur and are intended to those skilled in the art, though not expressly stated herein. These alterations, improvements, and modifications are intended to be suggested by this disclosure and are within the spirit and scope of the exemplary embodiments of this disclosure.

Moreover, certain terminology has been used to describe embodiments of the present disclosure. For example, the terms “one embodiment, ” “an embodiment, ” and/or “some embodiments” mean that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Therefore, it is emphasized and should be appreciated that two or more references to “an embodiment” or “one embodiment” or “an alternative embodiment” in various portions of this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined as suitable in one or more embodiments of the present disclosure.

Further, it will be appreciated by one skilled in the art, aspects of the present disclosure may be illustrated and described herein in any of a number of patentable classes or context including any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof. Accordingly, aspects of the present disclosure may be implemented entirely hardware, entirely software (including firmware, resident software, micro-code, etc. ) or combining software and hardware implementation that may all generally be referred to herein as a “unit, ” “module, ” or “system. ” Furthermore, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer-readable media having computer readable program code embodied thereon.

A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including electromagnetic, optical, or the like, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that may communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable signal medium may be transmitted using any appropriate medium, including wireless, wireline, optical fiber cable, RF, or the like, or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of the present disclosure may be written in any combination of one or more programming languages, including an object-oriented programming language such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB. NET, Python or the like, conventional procedural programming languages, such as the "C" programming language, Visual Basic, Fortran 2003, Perl, COBOL 2002, PHP, ABAP, dynamic programming languages such as Python, Ruby and Groovy, or other programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN) , or the connection may be made to an external computer (e.g., through the Internet using an Internet Service Provider) or in a cloud computing environment or offered as a service such as a Software as a Service (SaaS) .

Furthermore, the recited order of processing elements or sequences, or the use of numbers, letters, or other designations, therefore, is not intended to limit the claimed processes and methods to any order except as may be specified in the claims. Although the above disclosure discusses through various examples what is currently considered to be a variety of useful embodiments of the disclosure, it is to be understood that such detail is solely for that purpose, and that the appended claims are not limited to the disclosed embodiments, but, on the contrary, are intended to cover modifications and equivalent arrangements that are within the spirit and scope of the disclosed embodiments. For example, although the implementation of various components described above may be embodied in a hardware device, it may also be implemented as a software-only solution, e.g., an installation on an existing server or mobile device.

Similarly, it should be appreciated that in the foregoing description of embodiments of the present disclosure, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure aiding in the understanding of one or more of the various embodiments. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed subject matter requires more features than are expressly recited in each claim. Rather, claimed subject matter may lie in less than all features of a single foregoing disclosed embodiment.

Claims

A method implemented on a computing device for presenting traffic information of a road segment to a user, the computing device including a memory and one or more processors, the method comprising:

obtaining, from a server, by the one or more processors, historical track data of a plurality of vehicles that passed the road segment over a period, wherein the road segment is linked by an upstream intersection and a downstream intersection;

obtaining, by the one or more processors, a cycle pattern of a first traffic light and a cycle pattern of a second traffic light, the first traffic light being located at the downstream intersection, the second traffic light being located at the upstream intersection;

determining, by the one or more processors, a time-space diagram related to the road segment based on the historical track data of a plurality of vehicles, the cycle pattern of the first traffic light, and the cycle pattern of the second traffic light, wherein the time-space diagram includes:

a first graphic representation indicating to the cycle pattern of the first traffic light,

a second graphic representation indicating to the cycle pattern of the second traffic light, and

a third graphic representation indicating a length of a queue on the road segment formed by one or more vehicles of the plurality of vehicles; and

generating, by the one or more processors, a graphic user interface for providing the time-space diagram to the user.
The method of claim 1, wherein

the third graphic representation includes a first section; and

determining the time-space diagram includes:

determining, by the one or more processors, a free-flow speed of the road segment based on the historical track data of the plurality of vehicles; and

determining, by the one or more processors, the first section based on the free-flow speed of the road segment.
The method of claim 1 or claim 2, wherein

the third graphic representation includes a second section; and

determining the time-space diagram further includes:

determining, by the one or more processors, a back-propagation wave speed of the road segment based on the historical track data of the plurality of vehicles; and

determining, by the one or more processors, the second section based on the back-propagation wave speed of the road segment.
The method of any one of claims 1 to 3, wherein

the third graphic representation includes a third section, and

determining the time-space diagram further includes:

determining, by the one or more processors, a last vehicle in the queue based on the historical track data of the plurality of vehicles; and

determining, by the one or more processors, the third section based on a position of the last vehicle in the queue.
The method of claim 4, wherein the third section is parallel to the first graphic representation or the second graphic representation.
The method of claim 4 or claim 5, wherein the method further comprises:

determining, by the one or more processors, whether a length of the third section of the third graphic representation is greater than or equal to a length the first graphic representation or a length of the second graphic representation of the time-space diagram; and

displaying a visual representation relating to the third section based on a result of the determination that the length of the third section of the third graphic representation is greater than or equal to the length the first graphic representation or the length of the second graphic representation of the time-space diagram.
The method of claim 6, wherein the method further comprising:

determining, by the one or more processors, a duration of the queue based on a length of the third section, wherein the visual representation includes an indicator indicating the duration of the queue.
The method of claim 2, wherein determining the free-flow speed of the road segment comprises:

determining, by the one or more processors, a first parameter corresponding to a first status of the road segment based on the historical track data of the plurality of vehicles, wherein the first status is that a vehicle flow rate of the road segment is positively correlated to a vehicle density of the road segment corresponding to the vehicle flow rate; and

determining, by the one or more processors, the free-flow speed based on the first parameter.
The method of claim 3, wherein determining the back-propagation wave speed of the road segment comprises:

determining, by the one or more processors, a second parameter corresponding to a second status of the road segment based on the historical track data of the plurality of vehicles, wherein the second status is that a vehicle flow rate of the road segment is negatively correlated to a vehicle density of the road segment corresponding to the vehicle flow rate; and

determining, by the one or more processors, the back-propagation wave speed based on the second parameter.
The method of any one of claims 1 to 9, wherein the historical track data of the plurality of vehicles includes historical track data determined by and obtained from a user terminal located in a vehicle.
A system configured for presenting traffic information of a road segment to a user, comprising:

at least one non-transitory storage medium including a set of instructions; and

one or more processors in communication with the at least one non-transitory storage medium, wherein when executing the set of instructions, the one or more processors is directed to:

obtain, from a server historical track data of a plurality of vehicles that passed the road segment over a period, wherein the road segment is linked by an upstream intersection and a downstream intersection;

obtain a cycle pattern of a first traffic light and a cycle pattern of a second traffic light, the first traffic light being located at the downstream intersection, the second traffic light being located at the upstream intersection;

determine a time-space diagram related to the road segment based on the historical track data of a plurality of vehicles, the cycle pattern of the first traffic light, and the cycle pattern of the second traffic light, wherein the time-space diagram includes:

a first graphic representation indicating to the cycle pattern of the first traffic light,

a second graphic representation indicating to the cycle pattern of the second traffic light, and

a third graphic representation indicating a length of a queue on the road segment formed by one or more vehicles of the plurality of vehicles; and

generate a graphic user interface for providing the time-space diagram to the user.
The system of claim 11, wherein

the third graphic representation includes a first section; and

to determine the time-space diagram, the one or more processors are further directed to:

determine a free-flow speed of the road segment based on the historical track data of the plurality of vehicles; and

determine the first section based on the free-flow speed of the road segment.
The system of claim 11 or claim 12, wherein

the third graphic representation includes a second section; and

to determine the time-space diagram, the one or more processors are further directed to:

determine a back-propagation wave speed of the road segment based on the historical track data of the plurality of vehicles; and

determine the second section based on the back-propagation wave speed of the road segment.
The system of any one of claims 11 to 13, wherein

the third graphic representation includes a third section, and

to determine the time-space diagram, the one or more processors are further directed to:

determine a last vehicle in the queue based on the historical track data of the plurality of vehicles; and

determine the third section based on a position of the last vehicle in the queue.
The system of claim 14, wherein the third section is parallel to the first graphic representation or the second graphic representation.
The system of claim 14 or claim 15, wherein the one or more processors are further directed to:

determine whether a length of the third section of the third graphic representation is greater than or equal to a length the first graphic representation or a length of the second graphic representation of the time-space diagram; and

display a visual representation relating to the third section based on a result of the determination that the length of the third section of the third graphic representation is greater than or equal to the length the first graphic representation or the length of the second graphic representation of the time-space diagram.
The system of claim 16, wherein the one or more processors are further directed to:

determine a duration of the queue based on a length of the third section, wherein the visual representation includes an indicator indicating the duration of the queue.
Thesystem of claim 12, wherein determining the free-flow speed of the road segment comprises:

determining, by the one or more processors, a first parameter corresponding to a first status of the road segment based on the historical track data of the plurality of vehicles, wherein the first status is that a vehicle flow rate of the road segment is positively correlated to a vehicle density of the road segment corresponding to the vehicle flow rate; and

determining, by the one or more processors, the free-flow speed based on the first parameter.
The system of claim 13, wherein determining the back-propagation wave speed of the road segment comprises:

determine a second parameter corresponding to a second status of the road segment based on the historical track data of the plurality of vehicles, wherein the second status is that a vehicle flow rate of the road segment is negatively correlated to a vehicle density of the road segment corresponding to the vehicle flow rate; and

determine the back-propagation wave speed based on the second parameter.
The system of any one of claims 11 to 19, wherein the historical track data of the plurality of vehicles includes historical track data determined by and obtained from a user terminal located in a vehicle.
A non-transitory computer readable medium comprising executable instructions that, wherein when executed by at least one processor, the executable instructions cause the at least one processor to effectuate a method comprising:

obtaining, from a server, by the one or more processors, historical track data of a plurality of vehicles that passed the road segment over a period, wherein the road segment is linked by an upstream intersection and a downstream intersection;

obtaining, by the one or more processors, a cycle pattern of a first traffic light and a cycle pattern of a second traffic light, the first traffic light being located at the downstream intersection, the second traffic light being located at the upstream intersection;

determining, by the one or more processors, a time-space diagram related to the road segment based on the historical track data of a plurality of vehicles, the cycle pattern of the first traffic light, and the cycle pattern of the second traffic light, wherein the time-space diagram includes:

a first graphic representation indicating to the cycle pattern of the first traffic light,

a second graphic representation indicating to the cycle pattern of the second traffic light, and

a third graphic representation indicating a length of a queue on the road segment formed by one or more vehicles of the plurality of vehicles; and

generating, by the one or more processors, a graphic user interface for providing the time-space diagram to the user.