WO2022055452A1

WO2022055452A1 - Methods and systems for approach direction and lane specific vehicle detection at signalized roadway intersections and coordinated traffic signal control

Info

Publication number: WO2022055452A1
Application number: PCT/TR2021/050887
Authority: WO
Inventors: Emrah METLI
Original assignee: Metli Emrah
Priority date: 2020-09-08
Filing date: 2021-09-06
Publication date: 2022-03-17
Also published as: TR202014158A2

Abstract

The invention relates in general to systems and methods for vehicle detection at signalized roadway intersections and control of traffic signals at intersections, more specifically, detection of vehicles utilizing individual radio frequency signals emitted from onboard devices in vehicles and regulating the timing of traffic signals according to the detected number of vehicles at each approach direction of an intersection. A remote server receives vehicle information to determine the approach direction of vehicles to the intersection and the vehicle demand for each approach direction and then determines a timing plan for the traffic signals at the intersection according to the vehicle demand, taking into account the arrival time of vehicles from neighboring intersections.

Description

Methods and systems for approach direction and lane specific vehicle detection at signalized roadway intersections and coordinated traffic signal control

Field of the invention

The present disclosure relates in general to systems and methods for vehicle detection at signalized roadway intersections and control of traffic signals at intersections, more specifically, detection of vehicles utilizing individual radio frequency signals emitted from onboard devices in vehicles and regulating the timing of traffic signals according to the detected number of vehicles at each approach direction of an intersection.

Description of the prior art

There are two methods of traffic signal control at intersections; fixed time signal controllers operate according to predetermined fixed time slots allotted to each approach of an intersection and adaptive signal controllers which get information from vehicle detecting sensors installed at an intersection and regulate the timing of traffic signal lights according to changing demand in time for each approach of an intersection. Vehicle detection sensors utilized for adaptive traffic signal control and available on the market today include inductive loop detectors, magnetic detectors, microwave radar, infrared, ultrasonic, acoustic, and video image processor. Apart from these technologies, there are systems and methods known in the art which utilize radio frequency (RF) signals for vehicle detection purposes. These techniques are mainly based on the detection of RF signals emitted from an onboard device in a vehicle or response of a radio frequency identification tag (RFID) in a vehicle to an emitted RF signal for detection.

U.S. patent No. 9,922,556 discloses a system and method for allocating green light time of a traffic light at a given intersection by counting the number of vehicles located in an approach to a given intersection. The patent proposes mounting a control unit at an intersection, having directional antennas each of which facing a corresponding approach of the intersection and receiving periodically transmitted wireless identifying signals from mobile communication devices located in the vicinity of the intersection. Wireless identifying signals originated from passengers of a common vehicle or pedestrians are disregarded according to a value change of received signal strength indication. The location of a vehicle at a given approach of an intersection is also determined according to the received signal strength indication.

Japan patent application No. 2012008752 discloses a traffic signal system including traffic signals, a communication device, a storage device, and a signal light control device. The communication device receives vehicle information transmitted from radio equipment mounted on a vehicle, from each vehicle around an intersection, and stores it in the storage device. Vehicle information includes vehicle position and vehicle direction. The signal light control device regulates the signal light timing of each approach to an intersection according to the number of passing vehicles at each approach direction. One shortcoming of this patent application is the absence of explanation and clarity on how the approach direction of vehicles to an intersection is determined i.e. vehicle directions are not associated with the geometrical orientation of the approach lanes to the intersection.

U.S. patent No. 8,035,530 discloses a system and method for regulating the flow of traffic at a roadway intersection having one or more traffic signals by positioning a processor in the vicinity of the intersection to store cycle times of the traffic flow directions, mounting an RFID reader in the vicinity of each traffic signal in communication with the processor, interrogating with the RFID reader, an RFID tag on each vehicle at the intersection to count the number of vehicles present in each traffic flow direction at the intersection, calculating an unused time slice of the cycle time for a traffic flow direction and regulating the cycle time accordingly. One shortcoming of this patent is that even if an individual RFID reader is installed for every approach to an intersection to detect vehicles at that approach, for the reason that RF signals dissipate concentrically, each RFID reader will detect vehicles approaching from other directions as well as the intended approach of that individual RFID reader.

U.S. patent application No. 20090051568 discloses a computer-implemented method, apparatus, and computer usable program code for controlling traffic. A set of vehicles is monitored moving from one radio frequency identification tag sensor to another radio frequency identification tag sensor in a network of radio frequency identification tag sensors to detect movement of the set of vehicles. A set of traffic patterns is identified in response to detecting the movement of the set of vehicles. A determination is made as to whether a traffic pattern in the set of traffic patterns is a delayed traffic pattern. In response to a determination that the traffic pattern in the set of traffic patterns is the delayed traffic pattern for a traffic control light at an intersection, the timing of the traffic control light is changed to increase traffic flow through the intersection. U.S. patent No. 8,386,156 discloses a roadside equipment system and a corresponding method that can be used for controlling traffic signals. A method includes wirelessly receiving vehicle data from an onboard equipment system connected to a vehicle, the vehicle data including location data, time data, and vehicle identification. The method includes determining motion data (direction of travel) for the vehicle and determining the current state (the current phase of the traffic signal in a direction corresponding to the location data of the vehicles) of at least one traffic device. The method includes determining a roadway lane corresponding to the vehicle based on the motion data and the current state of the at least one traffic device and storing the vehicle and associated roadway lane. The roadside equipment system uses a processor to automatically self-learn the location and geometry of roadway lanes based on a historic correlation of vehicle movements to signal phase changes.

All of these methods and systems have certain limitations that can be solved by the desired characteristics of the present invention. Traditional vehicle detection sensors available today are either intrusive, meaning that they need to be installed under the pavement closing the lanes to vehicle traffic when installing and servicing, or unreliable and need regular maintenance such as inductive loop detectors and magnetic detectors or expensive such as microwave radar, ultrasonic, acoustic or sensitive to inclement weather such as video image processor and infrared. Vehicle detection methods and systems utilizing RF signals have also certain limitations as mentioned above which can be solved with the characteristic features of the present invention.

Summary of the invention

Accordingly, a general object of the present invention is to provide a novel and useful vehicle detection system and method in which the aforementioned disadvantages of the prior art are eliminated. Aspects and advantages of the invention will be outlined in part in the following description or may be learned through practice of the invention.

It is an object of the present invention to provide a method and system for detecting only RF signals of devices which are associated with vehicles so that eliminating other unrelated RF signals such as originating from pedestrians or passengers of vehicles in the vicinity of an intersection. It is an additional object of the present invention to provide a method and system for eliminating the use of unreliable received signal strength indication (RSSI) values of RF signals to determine unrelated sources other than vehicles, approach directions, and location of a vehicle at a given approach.

It is an additional object of the present invention to provide a method and system for eliminating the use of directional antennas to determine the approach directions of vehicles to an intersection.

It is an additional object of the present invention to provide a method and system for coordinating neighboring intersections to smooth out traffic at a city level.

It is an additional object of the present invention to provide a method and system for eliminating the need to install specific transceiver devices such as RFID tags in a vehicle.

It is an additional object of the present invention to provide a method and system for identifying movement or progress of individual vehicles along a route or path for purposes of coordination between neighboring intersections.

It is an additional object of the present invention to provide a method and system for eliminating the need to process location data received from vehicles to determine by selflearning the location and the geometry of roadway lanes based on a historic correlation of vehicle movements to signal phase changes so that eliminating the need of powerful processing by the roadside devices deployed at the intersections.

One exemplary embodiment of the present invention provides a computer-implemented method of vehicle detection at signalized intersections for traffic signal phase and timing control. The method includes initiating a wireless connection or communication link between a road-side unit and at least an onboard device. Receiving an identification number of the road-side unit and transmitting this identification number and vehicle information such as vehicle or onboard device ID, heading and, RSSI to a remote server by at least an onboard device. Determining by the server, the approach direction of the vehicle to the intersection, taking into account the heading information of the vehicle and orientation information of the intersection. Determining by the server whether the vehicle is moving or stationary according to the change in received RSSI value from the onboard device and associating the vehicle with a lane and a corresponding traffic signal light which controls that lane, taking into account the current phase of the traffic signal lights at that intersection. Determining by the server the vehicle demand, i.e. the number of vehicles passing or waiting at each approach direction and each lane of the intersection. Determining by the server a timing plan for the traffic signals at the intersection according to the vehicle demand, taking into account the arrival time of vehicles from neighboring intersections. Transmitting by the server the determined timing plan to the traffic signal controller at the intersection and executing the timing plan by the traffic signal controller.

As mentioned herein, various features can be used in various combinations for any embodiment. In a particular implementation of this exemplary embodiment, heading information as a piece of vehicle information is generated by the onboard device utilizing either GPS or a digital compass associated with the onboard device. In another particular implementation of this exemplary embodiment, vehicle information is transmitted to the remote server by the onboard device at regular intervals e.g. at every one second or another predefined period. In another particular implementation of this exemplary embodiment, communication between the onboard device and the remote server is accomplished utilizing the cellular network data connection of the onboard device through the Internet. In another particular implementation of this exemplary embodiment, orientation (i.e. geographical positioning or geometry) information of the intersection and identification number of the roadside unit associated with that intersection are stored in advance in the memory of the remote server.

Another exemplary embodiment of the present invention provides a data processing system of vehicle detection at signalized intersections for traffic signal phase and timing control. The system includes a road-side unit placed at a roadway intersection comprising wireless communication technologies, processor and memory; at least an onboard device associated with a vehicle and in communication with a remote server, comprising wireless communication technologies, screen, speaker, processor and memory, initiating connection or communication link with a road-side unit, receiving a road-side unit identification number and transmitting the road-side unit identification number and vehicle information such as vehicle or onboard device ID, heading and RSSI to the remote server; one of a GPS module or a digital compass associated with the onboard device, determining the heading of the vehicle; a remote server comprising processor and memory, storing orientation information of intersections and all connected vehicle information, receiving from at least an onboard device, an identification number of the road-side unit and vehicle information, determining the approach direction of each vehicle to the intersection taking into account the heading information of each vehicle and orientation information of the intersection, determining whether a vehicle is moving or stationary according to the change in received RSSI value from the onboard device and associating each vehicle with a lane and a corresponding traffic signal light which controls that lane, taking into account the current phase of the traffic signal lights at that intersection, determining the vehicle demand i.e. the number of vehicles passing or waiting at each approach direction and each lane of the intersection, determining a timing plan for the traffic signals at the intersection according to the vehicle demand, taking into account the arrival time of vehicles from neighboring intersections and transmitting the determined timing plan to the traffic signal controller at the intersection; a traffic signal controller located at the roadway intersection and in communication with the remote server, receiving and executing the timing plans determined by the remote server.

As mentioned herein, various features can be used in various combinations for any embodiment. In a particular implementation of this exemplary embodiment, the onboard device can act as a wireless access point or gateway to a backend network which houses a server with its possession of wireless communication technologies and software application configured to transmit a received identification number of a road-side unit and vehicle information to a remote server.

In another particular implementation of this exemplary embodiment, the onboard device can be an electronic device such as a smartphone associated with a vehicle and in communication with a remote server, comprising wireless communication technologies, one of a GPS module or a digital compass, processor, memory, screen, speaker and software application configured to communicate with the remote server, initiate connection or communication link with the road-side unit, receive the road-side unit identification number and transmit the road-side unit identification number and vehicle information such as vehicle or onboard device ID, heading and RSSI to the remote server.

Another exemplary embodiment of the present invention provides another computer- implemented method of vehicle detection at signalized intersections for traffic signal phase and timing control. The method includes initiating a wireless connection or communication link between a road-side unit and at least an onboard device. Receiving vehicle information such as vehicle or onboard device ID, heading, and RSSI and transmitting this vehicle information and identification number of the road-side unit to a remote server by the roadside unit. Determining by the server, the approach direction of the vehicle to the intersection, taking into account the heading information of the vehicle and orientation information of the intersection. Determining by the server whether the vehicle is moving or stationary according to the change in received RSSI value from the onboard device and associating the vehicle with a lane and a corresponding traffic signal light which controls that lane, taking into account the current phase of the traffic signal lights at that intersection. Determining by the server the vehicle demand, i.e. the number of vehicles passing or waiting at each approach direction and each lane of the intersection. Determining by the server a timing plan for the traffic signals at the intersection according to the vehicle demand, taking into account the arrival time of vehicles from neighboring intersections. Transmitting by the server the determined timing plan to the traffic signal controller at the intersection and executing the timing plan by the traffic signal controller.

As mentioned herein, various features can be used in various combinations for any embodiment. In a particular implementation of this exemplary embodiment, heading information as a piece of vehicle information is generated by the onboard device utilizing either GPS or a digital compass associated with the onboard device. In another particular implementation of this exemplary embodiment, vehicle information is transmitted to the roadside unit by the onboard device at regular intervals e.g. at every one second or another predefined period. In another particular implementation of this exemplary embodiment, communication between the road-side unit and the remote server is accomplished utilizing a communication network such as Wide Area Network (WAN) or cellular network etc. In another particular implementation of this exemplary embodiment, orientation (i.e. geographical positioning or geometry) information of the intersection and identification number of the road-side unit associated with that intersection are stored in advance in the memory of the remote server.

Another exemplary embodiment of the present invention provides another data processing system of vehicle detection at signalized intersections for traffic signal phase and timing control. The system includes a road-side unit placed at a roadway intersection comprising wireless communication technologies, processor and memory; at least an onboard device associated with a vehicle and in communication with the road-side unit, comprising wireless communication technologies, screen, speaker, processor and memory, initiating connection or communication link with the road-side unit, and transmitting vehicle information such as vehicle or onboard device ID, heading and RSSI to the road-side unit; one of a GPS module or a digital compass associated with the onboard device, determining the heading of the vehicle; a remote server comprising processor and memory, storing orientation information of intersections and all connected vehicle information, receiving from the road-side unit, an identification number of the road-side unit and connected vehicle information, determining the approach direction of each vehicle to the intersection taking into account the heading information of each vehicle and orientation information of the intersection, determining whether a vehicle is moving or stationary according to the change in received RSSI value from the road-side unit and associating each vehicle with a lane and a corresponding traffic signal light which controls that lane, taking into account the current phase of the traffic signal lights at that intersection, determining the vehicle demand i.e. the number of vehicles passing or waiting at each approach direction and each lane of the intersection, determining a timing plan for the traffic signals at the intersection according to the vehicle demand, taking into account the arrival time of vehicles from neighboring intersections and transmitting the determined timing plan to the traffic signal controller at the intersection; a traffic signal controller located at the roadway intersection and in communication with the remote server, receiving and executing the timing plans determined by the remote server.

As mentioned herein, various features can be used in various combinations for any embodiment. In a particular implementation of this exemplary embodiment, the onboard device can be an electronic device such as a smartphone associated with a vehicle and in communication with a road-side unit, comprising wireless communication technologies, one of a GPS module or a digital compass, processor, memory, screen, speaker and software application configured to communicate with the road-side unit, initiate connection or communication link with the road-side unit, and transmit the vehicle information such as vehicle or onboard device ID, heading and RSSI to the road-side unit.

Another exemplary embodiment of the present invention provides a non -transitory computer- readable storage medium comprising instructions in code which when loaded into a memory and executed by a processor of a computing device cause the computing device to determine the approach directions of vehicles to a roadway intersection taking into account the heading information of the vehicles and orientation information of the intersection; determine whether each individual vehicle is moving or stationary according to the change in received RSSI value from the onboard devices or the road-side unit and associate each vehicle with a lane and a corresponding traffic signal light which controls that lane, taking into account the current phase of the traffic signal lights at that intersection; determine the vehicle demand, i.e. the number of vehicles passing or waiting at each approach direction and each lane of the intersection and determine a timing plan for the traffic signals at the intersection according to the vehicle demand, taking into account the arrival time of the vehicles from neighboring intersections. Structural and characteristic features and all advantages of the present invention will be better understood with reference to the figures and detailed explanations and must be evaluated in light of these detailed explanations with reference to the figures.

Brief description of the drawings

Figure 1 , illustrates an exemplary vehicle detection system and method at a signalized intersection for traffic signal phase and timing control.

Figure 2, illustrates another exemplary vehicle detection system and method at a signalized intersection for traffic signal phase and timing control.

Figure 3, is a depiction of an onboard device.

Figure 4, is a depiction of a road-side unit.

Description of the preferred embodiments

In this detailed description, a few exemplary embodiments of the invention are explained via figures solely for the purposes of better understanding of the subject and not limitations of the invention to these examples. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention.

As will be appreciated by one skilled in the art, the present invention may be embodied as a method, system or computer program product. Any of the methods disclosed herein may be implemented in hardware, software, firmware or any combination thereof. Where implemented as software, the method steps, acts or operations may be programmed or coded as computer-readable instructions and recorded electronically, magnetically or optically on a fixed, permanent, non-volatile or non-transitory computer-readable medium, computer-readable memory, machine-readable memory or computer program product. In other words, computer-readable memory or computer-readable medium comprises instructions in code which when loaded into a memory and executed on a processer of a server or other computing device cause the computing device to perform one or more of the foregoing methods.

Furthermore, the invention can take the form of a computer program product accessible from a computer-usable or computer-readable medium providing program code for use by or in connection with a computer or any instruction execution system. For the purposes of this description, a computer-usable or computer-readable medium can be any apparatus that can contain, store, communicate, propagate or transport the program for use by or in connection with the instruction execution system, apparatus or device. The computer-useable medium may include a propagated data signal with the computer-usable program code embodied therewith either in baseband or as part of a carrier wave. The computer-useable program code may be transmitted using any appropriate medium including but not limited to the Internet, wireline, optical fiber cable, radio frequency etc.

The technology discussed herein makes reference to servers, access points, gateways, software applications and other computer-based and electronic systems as well as actions taken and information sent to and from such systems. One of ordinary skill in the art will recognize that the inherent flexibility of computer-based systems allows for a great variety of possible configurations of components. For example, server processes discussed herein may be implemented using a single server or multiple servers working in combination. Applications may be implemented on a single system or distributed across multiple systems. Distributed components may operate sequentially or in parallel.

The present disclosure also makes reference to the relay of communicated data over one or more communications networks. It should be appreciated that network communications can comprise sending and/or receiving information over one or more networks of various forms. For example, a network can comprise a local area network (LAN), wide area network (WAN), the Internet, cellular networks or other type(s) of networks. A network may comprise any number and/or combination of hard-wired, wireless or other communication links.

As used herein, the term orientation of intersections is intended to refer to geographical positioning or geometry of intersections. The term geographical positioning is intended to refer to the direction of every roadway such as north, south, east, west or any other direction in between of those coming together at an intersection which can be defined as the point of crossing of two or more roadways. As used herein, the term GPS is intended to refer to all global navigation satellite systems that have different names in different countries.

As used herein, the term heading is intended to refer to the moving directions formed by the changing coordinates of the vehicles in time, determined by GPS, resulting from the movements of the vehicles or the current direction of a vehicle determined by a digital compass.

As used herein, with the association of an onboard device with a vehicle it is meant that an onboard device is situated within and carried with a vehicle and detecting the movements and current direction of the vehicle.

As used herein, the term phase of the traffic signal lights is intended to describe every individual component of these lights in red, yellow and green colors.

Generally, the present disclosure is directed to computer implemented methods, data processing systems and a non-transitory computer readable storage medium to detect vehicles at signalized intersections for traffic signal phase and timing control. Figure 1 illustrates an exemplary vehicle detection system and method at a signalized intersection for traffic signal phase and timing control according to an exemplary embodiment of the present disclosure. As depicted by way of example in Figure 1 , the onboard devices (not shown) in groups of vehicles 101 , 102, 103 and 104 approaching an intersection from different directions initiate a wireless connection as soon as they enter wireless communication range with a road-side unit (105) located near the intersection. After initiating a wireless connection, the onboard devices in groups of vehicles 101 , 102, 103 and 104 receive the identification number of the road-side unit (105) and transmit this identification number of the road-side unit (105) and own vehicle information such as vehicle or onboard device ID, heading and RSSI to a remote server 110. Vehicle information such as heading is generated by the onboard devices associated with the vehicles. Heading of the vehicles are determined either by GPS modules (not shown) associated with the onboard devices and in communication with GPS satellites 106 or by digital compasses (not shown) associated with the onboard devices. Vehicle information is transmitted to the remote server by the onboard device at regular intervals e.g. at every one second or another predefined period. In this particular implementation, onboard devices with their possession of wireless communication technologies and software application, act as wireless access points or gateways to a backend network which houses the remote server 110, utilizing one or more cellular network base stations 107, network gateway 108, and a data network 109 (e.g. the Internet) to transmit the identification number of the road-side unit (105) and vehicle information to the remote server 110. The orientation information of all intersections and identification number of all road-side units are associated with each other and stored in a database on a local memory of the remote server 110 or a separate database 111 and the intersection which the group of vehicles 101 , 102, 103 and 104 are approaching is determined from the received identification number of the road-side unit 105. The approach direction of each vehicle to the intersection is determined by the remote server 110 with the software and algorithm it possesses, utilizing the orientation information of the intersection and heading of the vehicles. In the exemplary embodiment of Figure 1 , the orientation of the intersection in compass grades is defined as 0°, 90°, 180°, 270° and vehicle group 101 moving towards west with a heading of 270° is associated with the approach direction 270° and traffic signals controlling that direction, vehicle group 102 moving towards south with a heading of 180° is associated with the approach direction 180° and traffic signals controlling that direction, vehicle group 103 moving towards east with a heading of 90° is associated with the approach direction 90° and traffic signals controlling that direction and vehicle group 104 moving towards north with a heading of 0° is associated with the approach direction 0° and traffic signals controlling that direction. Every individual intersection is designated differently according to the unique orientation of that intersection. Whether a vehicle is moving or stationary is also determined by the remote server 110 according to the change in received RSSI value from the onboard device and the intersection situation map 100 as illustrated in the exemplary embodiment of Figure 1 is generated by the remote server 110 with the software and algorithm it possesses, associating each vehicle with a lane and corresponding traffic signal light which controls that lane, taking into account the current phase of the traffic signal lights at that intersection, determining the vehicle demand, i.e. the number of vehicles passing or waiting at each approach direction and each lane of the intersection. For example, at a specific approach direction to the intersection, vehicles with a relatively constant RSSI values are associated with the lane which is currently not allowed to proceed i.e. on a red signal and vehicles with changing RSSI values are associated with the lane which is currently allowed to proceed i.e. on a green signal. According to the intersection situation map 100 indicating vehicle demand at each approach direction and lane, a timing plan for the traffic signals is determined by the server 110, taking into account the arrival time of vehicles from neighboring intersections. The information on the arrival time of vehicles from neighboring intersections are determined by the server 110 from the departure time of vehicles from a neighboring intersection and distance between the two intersections. To achieve that, neighboring intersections are associated with each other with the distances between each other in the memory of the remote server 110. The determined timing plan is transmitted to the traffic signal controller 112 at the intersection and executed by it.

The data network 109 represents one or more mechanisms by which a vehicle computer such as an onboard device may communicate with a remote server 110. Accordingly, the data network 109 may be one or more of various wired or wireless communication mechanisms including any desired combination of wired (e.g. cable and fiber) and/or wireless (e.g. cellular, satellite, microwave and radio frequency) communication mechanisms and any desired network topology or topologies when multiple communication mechanisms are utilized.

Figure 2 illustrates another exemplary vehicle detection system and method at a signalized intersection for traffic signal phase and timing control according to an exemplary embodiment of the present disclosure. As depicted by way of example in Figure 1 , the onboard devices (not shown) in groups of vehicles 201 , 202, 203 and 204 approaching an intersection from different directions initiate a wireless connection as soon as they enter wireless communication range with a road-side unit (205) located near the intersection. After initiating a wireless connection, the road side unit 205 receives vehicle information such as vehicle or onboard device ID, heading and RSSI and transmits each individual vehicle information and identification number of the road side unit to a remote server 210. Vehicle information such as heading is generated by the onboard devices associated with the vehicles. Heading of the vehicles are determined either by GPS modules (not shown) associated with the onboard devices and in communication with GPS satellites 206 or by digital compasses (not shown) associated with the onboard devices. Vehicle information is transmitted to the remote server by the road-side unit 205 at regular intervals e.g. at every one second or another predefined period. In this particular implementation, road-side unit with its possession of wireless communication technologies and firmware, act as gateway to a backend network which houses the remote server 210, utilizing one or more wireless access point or router 207, network gateway 208, and a data network 209 (e.g. the Internet) to transmit each vehicle information and the identification number of the road-side unit (205) to the remote server 210. The orientation information of all intersections and identification number of all road-side units are associated with each other and stored in a database on a local memory of the remote server 210 or a separate database 211 and the intersection which the group of vehicles 201 , 202, 203 and 204 are approaching is determined from the received identification number of the road-side unit 205. The approach direction of each vehicle to the intersection is determined by the remote server 210 with the software and algorithm it possesses, utilizing the orientation information of the intersection and heading of the vehicles. In the exemplary embodiment of Figure 2, the orientation of the intersection in compass grades is defined as 0°, 90°, 180°, 270° and vehicle group 101 moving towards west with a heading of 270° is associated with the approach direction 270° and traffic signals controlling that direction, vehicle group 202 moving towards south with a heading of 180° is associated with the approach direction 180° and traffic signals controlling that direction, vehicle group 203 moving towards east with a heading of 90° is associated with the approach direction 90° and traffic signals controlling that direction and vehicle group 204 moving towards north with a heading of 0° is associated with the approach direction 0° and traffic signals controlling that direction. Every individual intersection is designated differently according to the unique orientation of that intersection. Whether a vehicle is moving or stationary is also determined by the remote server 210 according to the change in received RSSI value from the road-side unit and the intersection situation map 200 as illustrated in the exemplary embodiment of Figure 2 is generated by the remote server 210 with the software and algorithm it possesses, associating each vehicle with a lane and corresponding traffic signal light which controls that lane, taking into account the current phase of the traffic signal lights at that intersection, determining the vehicle demand, i.e. the number of vehicles passing or waiting at each approach direction and each lane of the intersection. For example, at a specific approach direction to the intersection, vehicles with a relatively constant RSSI values are associated with the lane which is currently not allowed to proceed i.e. on a red signal and vehicles with changing RSSI values are associated with the lane which is currently allowed to proceed i.e. on a green signal. According to the intersection situation map 200 indicating vehicle demand at each approach direction and lane, a timing plan for the traffic signals is determined by the server 210, taking into account the arrival time of vehicles from neighboring intersections. The information on the arrival time of vehicles from neighboring intersections are determined by the server 210 from the departure time of vehicles from a neighboring intersection and distance between the two intersections. To achieve that, neighboring intersections are associated with each other with the distances between each other in the memory of the remote server 210. The determined timing plan is transmitted to the traffic signal controller 212 at the intersection and executed by it.

The data network 209 represents one or more mechanisms by which a vehicle computer such as an onboard device may communicate with a remote server 210. Accordingly, the data network 209 may be one or more of various wired or wireless communication mechanisms including any desired combination of wired (e.g. cable and fiber) and/or wireless (e.g. cellular, satellite, microwave and radio frequency) communication mechanisms and any desired network topology or topologies when multiple communication mechanisms are utilized.

Figure 3 is a depiction of an onboard device 300 associated with a vehicle on which the present invention may be implemented. The onboard device 300 includes a processor 301 , flash memory 302 and/or random-access memory 303 for executing one or more applications. As depicted by way of example in Figure 3, the onboard device 300 includes a user interface 304 for interacting with the onboard device 300 and its applications. The user interface 304 may include one or more input/output devices such as a display screen 305 (e.g. an LCD or LED screen or touch sensitive display screen) and a keyboard or keypad 306.

According to an exemplary embodiment of the present invention, the onboard device 300 may include a transceiver 307 for communicating with data network 109. The transceiver 307 may be a radio frequency (RF) transceiver for wirelessly communicating with one or more base stations 107 over a cellular wireless network using cellular communication protocols and standards for both voice calls and packet data transfer such as GSM, CDMA, GPRS, EDGE, UMTS, LTE etc.

The onboard device 300 includes a Bluetooth module 308 for communicating with road-side units over a communication link. A Bluetooth device can operate in three main states. It can either be advertising, scanning or connected. To get the onboard device and a road side unit connected, the road-side unit advertises and the onboard device scans for it or vice versa and then initiate a connection. Advertising essentially involves broadcasting packets which allow another scanning device to discover them. The onboard device 300 may alternatively include Wi-Fi, DSRC, or other radio frequency communication protocols, visible light communication technologies like Li-Fi or infrared communication technologies like UV for communicating with road-side units over a communication link.

To implement the vehicle detection technology of the present invention, the onboard device 300 depicted by way of example in Figure 3 uses the position determining subsystem 309 to determine a current heading of a vehicle. The position determining subsystem 309 includes a GPS module 310 to determine heading of a vehicle from subsequent locations of the vehicle in a certain time interval. The determined heading of a vehicle is stored in the memory (302, 303) and transmitted to a road-side unit or a remote server when connected to a road-side unit for certain embodiments. The heading of a vehicle is updated and saved in memory (302, 303) at regular intervals. An accelerometer 311 and/or a digital compass 312 and/or a gyroscope 313 may also be used alternatively or in combination or addition to a GPS module 310 to determine a current heading of a vehicle. These sensors 311 , 312 and 313 associated with the onboard device may act as a navigation aid to continuously calculate by dead reckoning the heading of a vehicle in cases where poor GPS connection may arise.

The processor 301 coupled to the memory (302, 303) enables the onboard device 300 to perform an action in the form of a computer-readable program code when a connection is initiated with a road-side unit such as receiving identification number of a road-side unit, transmitting this identification number and vehicle information to a remote server or transmitting vehicle information to a road-side unit. Driver can be notified visually and/or audibly using display screen 305 and/or speaker 314. Alternatively, driver can be provided with a haptic and/or tactile feedback.

Figure 4 is a depiction of a road-side unit 400 located near an intersection on which the present invention may be implemented. The road-side unit 400 includes a processor 401 and one or more memory 402 for executing one or more applications and includes a Bluetooth module 403 for communicating with onboard devices and wireless communication module 404 for communicating with a wireless access point or router over a communication link. The road side unit 400 may alternatively include Wi-Fi, DSRC or other radio frequency communication protocols, visible light communication technologies like Li-Fi or infrared communication technologies like UV for communicating with onboard devices over a communication link.

While the invention has been described with reference to exemplary embodiments, it would be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, the use of the term first, second etc. are used to distinguish one element from another.

Accordingly, it is to be understood that the present disclosure, including the above description and the accompanying figures and below claims is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent to those of skill in the art upon reading the above description. The scope of the invention should be determined not with reference to the above description but should instead be determined with reference to the claims appended hereto along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the arts discussed herein and that the disclosed systems and methods will be incorporated into such future embodiments. In summary, it should be understood that the disclosed subject matter is capable of modification and variation.

Computing devices generally include instructions executable by one or more computing devices such as those identified above and for carrying out blocks or steps of processes described above. Computer executable instructions may be compiled or interpreted from computer programs created using a variety of programming languages and/or technologies. In general, a processor (e.g. a microprocessor) receives instructions, e.g. from a memory, a computer-readable medium etc. and executes these instructions, thereby performing one or more processes, including one or more processes described herein. Such instructions and other data may be stored and transmitted using a variety of computer-readable media. A file in the computing device is generally a collection of data stored on a computer-readable medium such as a storage medium, a random-access memory etc. A computer-readable medium includes any medium that participates in providing data (e.g. instructions) which may be read by a computer. Such a medium may take any forms including but not limited to nonvolatile media, volatile media etc.

Claims

CLAIMS A computer implemented method of vehicle detection at signalized intersections for traffic signal phase and timing control, the method comprising:

• initiating a wireless connection or communication link between a road-side unit and at least an onboard device,

• receiving an identification number of a road-side unit by at least an onboard device,

• transmitting the identification number of a road-side unit and vehicle information such as vehicle or onboard device ID, heading and RSSI to a remote server by at least an onboard device,

• determining by the server, the approach direction of a vehicle to the intersection, taking into account the heading information of the vehicle and the orientation information of the intersection,

• determining by the server whether a vehicle is moving or stationary according to the change in received RSSI value from the onboard device and associating the vehicle with a lane and a corresponding traffic signal light which controls that lane, taking into account the current phase of the traffic signal lights at that intersection,

• determining by the server the vehicle demand, i.e. the number of vehicles passing or waiting at each approach direction and each lane of the intersection,

• determining by the server a timing plan for the traffic signals at the intersection according to the vehicle demand, taking into account the arrival time of vehicles from neighboring intersections,

• transmitting by the server the determined timing plan to a traffic signal controller at the intersection and executing the timing plan by the traffic signal controller. The method of claim 1 , wherein heading information as a piece of vehicle information is generated by the onboard device utilizing either GPS or a digital compass associated with the onboard device. The method of claim 1 , wherein vehicle information is transmitted to the remote server by an onboard device at regular intervals e.g. at every one second or another predefined period. The method of claim 1 , wherein communication between an onboard device and the remote server is accomplished utilizing the cellular network data connection of the onboard device through the Internet. The method of claim 1 , wherein orientation information of the intersection and identification number of the road-side unit associated with that intersection are stored in advance in the memory of the remote server. A computer implemented method of vehicle detection at signalized intersections for traffic signal phase and timing control, the method comprising:

• receiving vehicle information such as vehicle or onboard device ID, heading and RSSI from at least an onboard device and transmitting this vehicle information and identification number of the road-side unit to a remote server by a road-side unit,

• transmitting by the server the determined timing plan to a traffic signal controller at the intersection and executing the timing plan by the traffic signal controller. The method of claim 6, wherein heading information as a piece of vehicle information is generated by the onboard device utilizing either GPS or a digital compass associated with the onboard device. The method of claim 6, wherein vehicle information is transmitted to the remote server by an onboard device at regular intervals e.g. at every one second or another predefined period. 9. The method of claim 6, wherein communication between a road-side unit and the remote server is accomplished utilizing a communication network such as Wide Area Network (WAN) or cellular network etc.

10. The method of claim 6, wherein orientation information of the intersection and identification number of the road-side unit associated with that intersection are stored in advance in the memory of the remote server.

11. A non-transitory computer readable storage medium comprising instructions in code which when loaded into a memory and executed by a processor of a computing device cause the computing device to;

• determine the approach directions of vehicles to a roadway intersection taking into account the heading information of the vehicles and orientation information of the intersection,

• determine whether each individual vehicle is moving or stationary according to the change in RSSI value received from the onboard devices and associate each vehicle with a lane and a corresponding traffic signal light which controls that lane, taking into account the current phase of the traffic signal lights at that intersection,

• determine the vehicle demand, i.e. the number of vehicles passing or waiting at each approach direction and each lane of the intersection,

• determine a timing plan for the traffic signals at the intersection according to the vehicle demand, taking into account the arrival time of the vehicles from neighboring intersections.

12. A data processing system of vehicle detection at signalized intersections for traffic signal phase and timing control, the system comprising:

• a road-side unit placed at a roadway intersection comprising wireless communication technologies, processor and memory,

• at least an onboard device associated with a vehicle and in communication with a remote server, comprising wireless communication technologies, screen, speaker, processor and memory, initiating connection or communication link with a road-side unit, receiving a road-side unit identification number and transmitting the road-side unit identification number and vehicle information such as vehicle or onboard device ID, heading and RSSI to the remote server,

• one of a GPS module or a digital compass associated with the onboard device, determining the heading of the vehicle, 21

• a remote server comprising processor and memory, storing orientation information of intersections and all connected vehicle information, receiving from at least an onboard device, an identification number of the road-side unit and vehicle information, determining the approach direction of the vehicle to the intersection taking into account the heading information of the vehicle and orientation information of the intersection, determining whether the vehicle is moving or stationary according to the change in received RSSI value from the onboard device and associating the vehicle with a lane and a corresponding traffic signal light which controls that lane, taking into account the current phase of the traffic signal lights at that intersection, determining the vehicle demand i.e. the number of vehicles passing or waiting at each approach direction and each lane of the intersection, determining a timing plan for the traffic signals at the intersection according to the vehicle demand, taking into account the arrival time of vehicles from neighboring intersections and transmitting the determined timing plan to the traffic signal controller at the intersection,

• a traffic signal controller located at the roadway intersection and in communication with the remote server, receiving and executing the timing plans determined by the remote server. The system of claim 12, wherein onboard device can act as a wireless access point or gateway to a backend network which houses a server with its possession of wireless communication technologies and software application configured to transmit a received identification number of a road-side unit and vehicle information to a remote server. The system of claim 12, wherein onboard device can be an electronic device such as a smartphone associated with a vehicle and in communication with a remote server, comprising wireless communication technologies, one of a GPS module or a digital compass, processor, memory, screen, speaker and software application configured to communicate with the remote server, initiate connection or communication link with the road-side unit, receive the road-side unit identification number and transmit the road-side unit identification number and vehicle information such as vehicle or onboard device ID, heading and RSSI to the remote server. A data processing system of vehicle detection at signalized intersections for traffic signal phase and timing control, the system comprising:

• a road-side unit placed at a roadway intersection comprising wireless communication technologies, processor and memory, 22

• at least an onboard device associated with a vehicle and in communication with the road-side unit, comprising wireless communication technologies, screen, speaker, processor and memory, initiating connection or communication link with the road-side unit, and transmitting vehicle information such as vehicle or onboard device ID, heading and RSSI to the road-side unit,

• one of a GPS module or a digital compass associated with the onboard device, determining the heading of the vehicle,

• a remote server comprising processor and memory, storing orientation information of intersections and all connected vehicle information, receiving from the road-side unit, an identification number of the road-side unit and connected vehicle information, determining the approach direction of each vehicle to the intersection taking into account the heading information of each vehicle and orientation information of the intersection, determining whether a vehicle is moving or stationary according to the change in received RSSI value from the road-side unit and associating the vehicle with a lane and a corresponding traffic signal light which controls that lane, taking into account the current phase of the traffic signal lights at that intersection, determining the vehicle demand i.e. the number of vehicles passing or waiting at each approach direction and each lane of the intersection, determining a timing plan for the traffic signals at the intersection according to the vehicle demand, taking into account the arrival time of vehicles from neighboring intersections and transmitting the determined timing plan to the traffic signal controller at the intersection,

• a traffic signal controller located at the roadway intersection and in communication with the remote server, receiving and executing the timing plans determined by the remote server. The system of claim 15, wherein onboard device can be an electronic device such as a smartphone associated with a vehicle and in communication with a road-side unit, comprising wireless communication technologies, one of a GPS module or a digital compass, processor, memory, screen, speaker and software application configured to communicate with the road-side unit, initiate connection or communication link with the road-side unit, and transmit the vehicle information such as vehicle or onboard device ID, heading and RSSI to the road-side unit.