DETECTION AREA SETTING METHOD FOR DETECTING PASSING VEHICLES, AND TRAFFIC SIGNAL CONTROL METHOD USING SAME
20180005521 · 2018-01-04
Inventors
Cpc classification
International classification
G08G1/065
PHYSICS
Abstract
The present invention relates to a detection area setting method for detecting passing vehicles, and a traffic signal control method using the same and, more particularly, to a detection area setting method for detecting passing vehicles, and a traffic signal control method using the same, the detection area setting method being capable of enabling smooth traffic operation at a crossroad, for example preventing a spillback phenomenon, minimizing green time (green light display time) during which there are no passing vehicles, and extending the green time, if needed, by setting one or a plurality of detection areas at a crossroad so as to detect the traffic volume in respective moving directions of vehicles at a signalized intersection, determining the traffic state in the moving directions of the vehicles according to vehicle information in respective detection areas, and automatically controlling the crossroad signals accordingly.
Claims
1-14. (canceled)
15. A method of controlling a traffic signal, wherein: in setting a detection area in which vehicle pass information within an intersection is detected using image detection or loop detection or both the image detection and the loop detection, one or a plurality of the detection areas is set within the intersection in a circle, oval or polygon shape, a vehicle entering the intersection in response to a signal phase is detected in a different detection area for each green time movement (going-straight, a left-turn), one detection area is set to detect only one green time movement within one phase, and the detection area is configured to detect an occupied time (OT) and a gap time (GT) for each vehicle movement, traffic states according to green time movements are classified into a normal state (α state), a spillback-possible state (β state) and a no-vehicle movement state (γ state) based on vehicle pass information within the signal intersection detected in the set detection area, a controller differentially controls an intersection signal for each green time movement depending on the classified traffic state, and if a phase is able to be terminated in all of green time movements of the corresponding phase, the corresponding phase is terminated and a next phase is performed, if the traffic state is the β state, the traffic light of a corresponding β state green time movement is turned on in a red signal after a yellow signal, and in this state, if the corresponding green time movement is the state (γ state) in which there is no vehicle when residual green time criteria (RGTC) elapse or do not elapse, a green signal is turned on again.
16. The method of claim 15, wherein: if a green signal is turned on again because the corresponding β state green time movement is the state (γ state) in which there is no vehicle after a red signal is turned on, when a movement time reaches a phase end near time (PENT), the green signal is repeatedly extended up to extension limit green (ELG) by unit green (UG), if a movement point of time passes through the residual green time criteria (RGTC) after the red signal is turned on and the spillback-possible state (β state) continues in the phase end near time (PENT), the red signal is extended up to extension limit red (ELR) by unit red (UR), and if the corresponding green time movement is not the state (γ state) in which there is no vehicle or is not the normal state (α state) after the phase end near time (PENT) elapses, the corresponding phase is terminated.
17. A method of controlling a traffic signal, comprising processes of: in setting a detection area in which vehicle pass information within an intersection is detected using image detection or loop detection or both the image detection and the loop detection, setting one or a plurality of the detection areas within the intersection in a circle, oval or polygon shape, and setting one detection area to detect only one green time movement within one phase so that a vehicle entering the intersection in response to a signal phase is detected in a different detection area for each green time movement (going-straight, a left turn), wherein the detection area is configured to detect an occupied time (OT) and a gap time (GT) for each vehicle movement; classifying traffic states according to green time movements into a normal state (α state), a spillback-possible state (β state) and a no-vehicle movement state (γ state) based on vehicle pass information within the signal intersection detected in the set detection area, differentially controlling, by a controller, an intersection signal for each green time movement depending on the classified traffic state, and if a phase is able to be terminated in all of green time movements of the corresponding phase, terminating the corresponding phase and performing a next phase; and if the traffic state is the γ state, determining, by the controller, a crosswalk traffic light of a corresponding γ state green time movement, changing the traffic light of the corresponding γ state green time movement to a yellow signal if green is not turned on, then turning on the traffic light in a red signal, and turning on an alternative movement of the γ state green time movement in green if the movement time is earlier than residual green time criteria (RGTC).
18. The method of claim 17, wherein after the alternative movement is turned on in green, a pass state of the alternative movement is determined, and if the pass state of the alternative movement is the normal state (α state) even after a phase end near time (PENT) elapses, the green signal is extended up to extension limit green (ELG) by unit green (UG).
19. The method of claim 18, wherein a detection area identical with a detection area in a direction in which a movement has been stopped is used as a detection area of the alternative movement.
20. A method of controlling a traffic signal, comprising processes of: in setting a detection area in which vehicle pass information within an intersection is detected using image detection or loop detection or both the image detection and the loop detection, setting one or a plurality of the detection areas within the intersection in a circle, oval or polygon shape, and setting one detection area to detect only one green time movement within one phase so that a vehicle entering the intersection in response to a signal phase is detected in a different detection area for each green time movement (going-straight, a left turn), wherein the detection area is configured to detect an occupied time (OT) and a gap time (GT) for each vehicle movement; classifying traffic states according to green time movements into a normal state (α state), a spillback-possible state (β state) and a no-vehicle movement state (γ state) based on vehicle pass information within the signal intersection detected in the set detection area, differentially controlling, by a controller, an intersection signal for each green time movement depending on the classified traffic state, and if a phase is able to be terminated in all of green time movements of the corresponding phase, terminating the corresponding phase and performing a next phase; and when a green time approaches an end of the phase in the normal state (α state), extending the green time up to extension limit green (ELG) by unit green (UG) in a phase end near time (PENT).
21. The method of claim 20, wherein: the extension of the green time is applicable from the phase end near time (PENT) before the end of the phase for each green time movement, and a green time extension mode is set for each phase in advance.
Description
DESCRIPTION OF DRAWINGS
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MODE FOR INVENTION
[0039] The present invention is for preventing a spillback phenomenon in a signal intersection, reducing a green time when there is no vehicle passing, extending the green time when many vehicles are passing, and automatically performing green lighting in an alternative movement in a green time movement in which there is no passing vehicle, and performs signal control for each green time movement in a phase. To this end, the present invention enables accurate and efficient intersection signal control using a method of setting a detection area so that vehicle pass information for each green time movement within an intersection can be checked, determining a traffic state for each green time movement based on vehicle pass information in each set detection area within the intersection, and controlling an intersection signal for each green time movement in a phase.
[0040] In order to perform such a traffic signal control method, the present invention requires a system configured to include detection means (photographing means, a loop sensor, etc.) for obtaining vehicle pass information in a set detection area within an intersection, a traffic light which is disposed in the intersection and whose lighting is controlled in response to an input operation control signal, and a controller which determines a traffic state based on the vehicle pass information of the detection area transmitted by the detection means and controls the lighting of the traffic light disposed in the intersection based on the determined traffic state.
[0041] In this case, the controller is configured to include a traffic state determination unit which determines a traffic state, memory which determines a traffic state according to vehicle pass information and on which a variety of types of data and program for controlling a traffic light based on the determined traffic state have been recorded, a lighting control unit for a signal for controlling the lighting of the traffic light, and a control unit which outputs an operation control signal to the lighting control unit using the data of the memory in response to a signal transmitted by the traffic state determination unit.
[0042] All of such roles of the controller may be performed by a conventional signal controller, but only the traffic state determination unit may be separated as separate hardware and the roles of the control unit and the lighting control unit may be performed by the signal controller. Both the traffic state determination unit and the control unit may be separated as separate hardware and the role of the lighting control unit may be performed by the conventional signal controller.
[0043] The design of such separation of the role and separation of hardware of the controller may be easily changed by those skilled in the art, if necessary. An example in which a single controller performs the entire process of controlling a traffic signal, including the determination of a traffic state and corresponding lighting control, is described below.
[0044] Embodiments of the present invention are described in detail below with reference to the accompanying drawings.
[0045] First, terms necessary to describe the present invention are defined with reference to the drawings.
[0046]
[0048] The detection area set as described above may be formed in the shape or size of a quadrangle, a circle or an oval or may be formed in a polygon, such as a hexagon or an octagon, as shown in
[0049]
[0057] Although not proposed in
[0071] The embodiments of the present invention are described below based on the defined terms.
[0072] First, in setting a detection area, criteria for setting the detection area are as follows. Basically, in one detection area, only one green time movement within one phase is detected. The detection area is set so that all of vehicles that enter an intersection other than right-turn in one street connected to the intersection are detected.
[0073] For example, in a common four-way signal intersection, four detection areas for detecting vehicles passing within the intersection are set as shown in
[0074] Furthermore, in the intersection connection part of a target street, if going-straight is three carriageways and a detection area has a quadrangle shape, the length in the long side of the detection area must be a length in which all of going-straight vehicles in the three carriageways can be detected. The short side of the detection area is set to be an average stop interval or more between vehicles that wait for a signal in a street section. If the detection area has a circle, it is set so that all of going-straight vehicles passing in the diameter of the circle can be detected.
[0075] Furthermore, the detection area needs to be set so that a right-turn vehicle is not detected. The detection area is set so that the closest left-turn vehicle traffic line can be detected and is set at the location from which a vehicle can exit from an intersection most rapidly after the vehicle is detected in the detection area.
[0076] Examples in which detection areas are set based on the criteria are shown in
[0077] In the figures, an NE detection area within the intersection has been set based on a going-straight carriageway in an S direction intersection connection street. An ES detection area has been set based on a W direction, an SW detection area has been set based on an N direction, and a WN detection area has been set based on a going-straight carriageway in an E direction. The detection areas have been set so that a right-turn vehicle is not detected. The detection areas have been set so that not only a going-straight vehicle, but a close left-turn vehicle is detected. In the case of the NE detection area, a going-straight vehicle from the S direction to the N direction is detected. Furthermore, a left-turn vehicle from the N direction to the E direction is detected. Likewise, in the ES detection area, a going-straight vehicle from the W direction to the E direction and a left-turn vehicle from the E direction to the S direction are detected. In the SW detection area, a going-straight vehicle from the N direction to the S direction and a left-turn vehicle from the S direction to the W direction are detected. In the WN detection area, a going-straight vehicle from the E direction to the W direction is detected, and a left-turn vehicle from the W direction to the N direction is detected.
[0078] In the four detection areas set in the four-way signal intersection, only the detection data of two detection areas in a diagonal line direction is always used as detection data according to a signal phase.
[0079] In the four-way signal intersection shown in
TABLE-US-00001 TABLE 1 1 phase (1) 2 phase (2) 3 phase (3) 4 phase (4) moving detection moving detection moving detection moving detection direction area direction area direction area direction area going- NE Turn left NE going- ES Turn left ES straight N.fwdarw.E straight E.fwdarw.S S.fwdarw.N W.fwdarw.E going- SW Turn left SW going- WN Turn left WN straight S.fwdarw.W straight W.fwdarw.N N.fwdarw.S E.fwdarw.W
TABLE-US-00002 TABLE 2 1 phase (1) 2 phase (2) 3 phase (3) 4 phase (4) moving detection moving detection moving detection moving detection direction area direction area direction area direction area going- NE Turn left WN going- SW Turn left ES straight E.fwdarw.W straight W.fwdarw.E S.fwdarw.N N.fwdarw.S going- SW Turn left ES going- NE Turn left WN straight E.fwdarw.S straight W.fwdarw.N S.fwdarw.W N.fwdarw.E
[0080] Table 1 is an exemplary table of detection areas applied for each phase in the separation signal. Table 2 is an exemplary table of detection areas applied for each phase in the simultaneous signal. In Table 1 and Table 2, the direction or phase sequence is only one example for describing a phase method and may be different in an actual signal intersection.
[0081] In the separation signal of Table 1, the 1 phase is a going-straight signal between the south (S) and the north (N). A vehicle that moves from the south to the north is detected in the NE detection area. In the opposite direction, the occupied time of a vehicle that moves in the SW detection area in the diagonal direction of the NE detection area is detected.
[0082] In the next phase (2 phase), in the NE detection area in which the going-straight vehicle from the south to the north was detected in the 1 phase, a vehicle that turns left from the north (N) to the east (E) is detected. In the SW detection area of a diagonal line, a vehicle that turns left from the south (S) to the west (W) is detected.
[0083] In the 3 phase, in the WN detection area and the ES detection area not used in the 1 and the 2 phases and mutually located in the diagonal line, vehicles that go straight between the east (E) and the west (W) are detected. In the WN detection area, a going-straight vehicle that moves from the east (E) to the west (W) is detected. In the ES detection area, a going-straight vehicle that moves from the west (W) to the east (E) is detected.
[0084] In the WN detection area of the 4 phase, a vehicle that turns left from the west (W) to the north (N) is detected. In the ES detection area (ES), a vehicle that turns left from the east (E) to the south (S) is detected.
[0085] Even in the simultaneous signal of Table 2, as in the separation signal of Table 1, in one phase, two green time movements are detected in two detection areas located in a diagonal direction.
[0086] In the 1 phase, a vehicle that goes straight from the south (S) to the north (N) is detected in the NE detection area. A vehicle that turns left from the south (S) to the west (W) is detected in the SW detection area located in the diagonal line of the NE detection area.
[0087] In the 2 phase, detection is performed using the WN detection area and the ES detection area of a diagonal direction and not used in the 1 phase. In the WN detection area, a vehicle that goes straight from the east (E) to the west (W) is detected. In the ES detection area, a vehicle that turns left from the east (E) to the south (S) is detected.
[0088] In the 3 phase, a vehicle that goes straight from the north (N) to the south (S) and a vehicle that turns left from the north (N) to the east (E) are detected. A vehicle that turns left is detected in the NE detection area, and a vehicle that goes straight is detected in the SW detection area.
[0089] In the 4 phase, a green is turned on from the west (W) to the east (E) and from the west (W) to the north (N). A vehicle that goes straight is detected in the ES detection area (ES), and a vehicle that turns left is detected in the WN detection area.
[0090] In a detection area in a three-way signal intersection or a four-way signal intersection having narrows streets connected, criteria for setting a common four-way signal intersection (only a going-straight vehicle and left-turn vehicle are detected other than a right-turn vehicle) basically need to be satisfied. Two or one detection area is set depending on a condition, such as the inside of an intersection having a narrow width. If one detection area is large, a plurality of detection areas may be set, and the results of detection may be construed as being one result.
[0091]
[0092] Table 3 is an example showing the detection of each green time movement by disposing two detection areas in a three-way signal intersection.
TABLE-US-00003 TABLE 3 1 phase (φ 1) 2 phase (φ 2) 3 phase (φ 3) moving detection moving detection moving detection direction area direction area direction area going- W turn left E turn left E straight S.fwdarw.W E.fwdarw.S E.fwdarw.W going- E straight W.fwdarw.E
[0093] In the present invention, the transmission (sending) of vehicle detection information detected in a detection area, the transmission of results, interpreted by a traffic state analysis method based on a detected vehicle detection occupied time, to the intersection signal controller, and signal synchronization driving according to a signal control method of the present invention in the intersection signal controller comply with the existing method or are based on the existing method.
[0094] In the present invention, after a detection area within an intersection is set as described above, the controller first determines a phase green time movement of a vehicle, determines the vehicle pass information of the set detection area based on the phase green time movement, and analyses a traffic state.
[0095] In this case, a process of determining the phase green time movement may be omitted. The reason for this is that when a previous phase is terminated in the normal state, a vehicle within an intersection moves only in a predetermined direction along the phase within a range not having an illegal pass, and thus there is no problem in signal control although only the direction in which a vehicle passes is determined regardless of a phase green time movement. If an illegal pass vehicle generated at a point of time at which an orange or red light is changed is taken into consideration, an error range (e.g., when the number of traffic vehicles within a specific time after the start of a phase is a specific number or less) may be set and excluded from signal control when information of the corresponding error range is generated. In order to fundamentally prevent the generation of a signal control error attributable to an illegal pass or the like, a traffic state may be determined with respect to a green time movement previously set in a corresponding phase and signal control may be performed.
[0096] Meanwhile, detection information that belongs to vehicle pass information transmitted from a detection area and that is required in a process of determining a traffic state is the vehicle occupied time (OT) and the gap time (GT).
[0097] That is, in the case of a traffic state in which the vehicle occupied time (OT) is shorter than the occupied time criteria (OTC) and the gap time (GT) is shorter than the gap time criteria (GTC), it is determined to be the normal state (α state). When the vehicle occupied time (OT) is detected to be the occupied time criteria (OTC) or more set in a corresponding signal intersection, it is determined that delay (the spillback-possible state, the β state) has occurred in the signal intersection. When the gap time (GT) is longer than the gap time criteria (GTC) because there is no vehicle passing in a green signal, it is determined to be the state (γ state) in which there is no vehicle in a green time movement and that an unnecessary green time is in progress. Such a determination of the traffic state is performed in real time.
[0098] The controller controls an intersection signal based on the determination of the traffic state. If the traffic state of all of green time movements from detection information is the normal state (α state), the controller performs signal control in the normal mode. If the traffic state of a specific green time movement is the state (β state) having a good possibility of a spillback phenomenon or the state (γ state) in which there is no vehicle in a green time movement, the controller enters the control mode and performs signal control. If termination is possible in the normal state (α state) without the β state and the γ state, the controller checks the green signal extension mode and continues to proceed or terminates a phase and proceeds to a next phase.
[0099] In such signal control, all of a plurality of green time movements are not controlled identically, but are controlled for each green time movement in a movement phase (In general, two green time movements in one phase in the case of a four-way signal intersection operating in four phases, and two or one green time movement in one phase in the case of a three-way intersection operating in three phases).
[0100] Furthermore, a signal control process for the signal control includes the entire signal control process, and it is divided into a signal control process when one green time movement traffic state within a phase is the β state, a signal control process when one green time movement traffic state within a phase is the γ state, and a signal control process when a green time movement traffic state within a phase can be terminated in the α state.
[0101] In the above description, in the entire signal control, when a phase starts, the entire end-possible mode in a corresponding phase green time movement becomes OFF. When the spillback-possible state (β state) is generated for each green time movement, a process of controlling a signal in the spillback-possible state (β state) is executed. When the no-vehicle movement state (γ state) is generated, a process of controlling a signal in the no-vehicle movement state (γ state) is executed. When the phase end near time (PENT) is reached without the generation of the β state or the γ state, a process of controlling a signal in the normal state (α state) termination possible is executed. When the process is terminated, a next phase proceeds.
[0102] Furthermore, in the signal control process in the β state, the traffic light of a green time movement in the corresponding β state is turned on in a red signal after a yellow signal if a traffic state in any one green time movement is the spillback-possible state (β state).
[0103] In this state, when the green time movement in the corresponding β state becomes the no-vehicle movement state (γ state) without the lapse of the residual green time criteria (RGTC), the signal is turned in green again. After the phase end near time (PENT) elapses, when the extension application mode in the corresponding green time movement is ON, the green signal is repeatedly extended up to the extension limit green (ELG) by the unit green (UG). If a traffic state prior to the extension limit green (ELG) is not the normal state (α state), the entire end-possible mode becomes ON.
[0104] After a red signal is turned on, if a movement point of time passes through the residual green time criteria (RGTC) and continues to be the no-vehicle movement state (γ state) in the phase end near time (PENT), the red signal may be extended up to the extension limit red (ELR) by the unit red (UR).
[0105] In this process, when the no-vehicle movement state (γ state) is reached prior to the phase end near time (PENT), whether the extension mode is ON is checked in the phase end near time (PENT). If the extension mode is ON, the unit green (UG) is repeatedly extended within the extension limit green (ELG).
[0106] Furthermore, when the extension limit red (ELR) is reached or the no-vehicle movement state (γ state) is reached after the phase end near time (PENT), the end-possible mode of a green time movement becomes ON. When the end-possible mode of the green time movement in a different green time movement in the same phase is ON, a green time movement phase is stopped.
[0107] For another example, in the above description, in the signal control process in the γ state, when a traffic state in any one green time movement is the no-vehicle movement state (γ state), a crosswalk traffic light in a green time movement of the corresponding γ state is determined. When the crosswalk traffic light is not turned on in green, the traffic light of the green time movement in the corresponding γ state is turned on in a yellow signal and then turned on in a red signal and the end-possible mode becomes ON. When the end-possible mode of a different green time movement is ON, a corresponding phase is terminated.
[0108] Furthermore, when the end-possible mode of the different green time movement is not ON and is ahead of the residual green time criteria (RGTC), an alternative movement in a green time movement in the γ state is turned on in green, and the end-possible mode of the green time movement becomes OFF.
[0109] Furthermore, the traffic state of an alternative movement is determined. When the traffic state of the alternative movement is not the γ state and the traffic state is the normal state (α state) and the extension mode is ON after the lapse of the phase end near time (PENT), it may be extended up to the extension limit green (ELG) by the unit green (UG).
[0110] Furthermore, when a traffic state in a green time movement is the γ state even prior to the phase end near time (PENT) and the end-possible mode of a different green time movement in the same phase is ON, a corresponding phase is terminated.
[0111] Furthermore, when a traffic state is the γ state in a green signal extension, the end-possible mode becomes ON. When the end-possible mode of a different green time movement in the same phase is ON, a corresponding phase is terminated.
[0112] A detection area in an alternative movement is performed using the same detection means as that in the detection area in the direction in which a movement has been stopped. In the four-way intersection of
TABLE-US-00004 TABLE 4 4 phase (φ4) 1 phase (φ1) 2 phase (φ2) 3 phase (φ3) Alter- detection moving Alternative detection moving Alternative detection moving Alternative detection moving native area direction direction area direction direction area direction direction area direction direction NE {circle around (1)} {circle around (6)} NE {circle around (6)} {circle around (1)} ES {circle around (7)} {circle around (4)} ES {circle around (4)} {circle around (7)} going- turn turn going- going- turn turn going- straight left left straight straight left left straight S.fwdarw.N N.fwdarw.E N.fwdarw.E S.fwdarw.N W.fwdarw.E E.fwdarw.S E.fwdarw.S W.fwdarw.E SW {circle around (5)} {circle around (2)} SW {circle around (2)} {circle around (5)} WN {circle around (3)} {circle around (8)} WN {circle around (8)} {circle around (3)} going- turn turn going- going- turn turn going- straight left left straight straight left left straight N.fwdarw.S S.fwdarw.W S.fwdarw.W N.fwdarw.S E.fwdarw.W W.fwdarw.N W.fwdarw.N E.fwdarw.W
TABLE-US-00005 TABLE 5 4 phase (φ4) 1 phase (φ1) 2 phase (φ2) 3 phase (φ3) Alter- detection moving Alternative detection moving Alternative detection moving Alternative detection moving native area direction direction area direction direction area direction direction area direction direction NE {circle around (1)} {circle around (6)} WN {circle around (3)} {circle around (8)} SW {circle around (5)} {circle around (2)} ES {circle around (7)} {circle around (4)} going- turn going- turn going- turn going- turn straight left straight left straight left straight left S.fwdarw.N N.fwdarw.E E.fwdarw.W W.fwdarw.N N.fwdarw.S S.fwdarw.W W.fwdarw.E E.fwdarw.S SW {circle around (2)} {circle around (5)} ES {circle around (4)} {circle around (7)} NE {circle around (6)} {circle around (1)} WN {circle around (8)} {circle around (3)} turn going- turn going- turn going- turn going- left straight left straight left straight left straight S.fwdarw.W N.fwdarw.S E.fwdarw.S W.fwdarw.E N.fwdarw.E S.fwdarw.N W.fwdarw.N E.fwdarw.W
TABLE-US-00006 TABLE 6 1 phase (φ 1) 2 phase (φ 2) 3 phase (φ 3) Alter- Alter- Alter- moving native moving native moving native direction direction direction direction direction direction going- None turn left going- turn left going- straight S.fwdarw.W straight E.fwdarw.S straight E.fwdarw.W E.fwdarw.W E.fwdarw.W going- turn left going- going- straight E.fwdarw.S straight straight W.fwdarw.E W.fwdarw.E W.fwdarw.E
[0113] Furthermore, in the signal control process when the normal state (α state) can be terminated, if a green time movement in a corresponding phase does not correspond to the γ state or the β state and approaches the termination of the phase in the normal state (α state), when the movement extension mode is ON, a green time is extended up to the extension limit green (ELG) by the unit green (UG). When a traffic state is not the normal state (α state) or reaches the extension limit green (ELG), the end-possible mode becomes ON. When the end-possible mode of a different green time movement in the same phase is ON, a corresponding phase is terminated.
[0114] The extension of the green time may be applied from the phase end near time (PENT) prior to the termination of a phase for each green time movement. For example, when ON (1) is applied and OFF (0) is not applied, if the extension is designated as in Table 7 in the green time movement of Table 1, the green time can be extended when a vehicle continuously moves with respect to going-straight in each direction. The green time is not extended with respect to turning-left in each direction. Furthermore, the extension mode may become ON or OFF with respect to all of the directions.
[0115] Table 7 shows an example in which a green time movement is selected in the extension of a green time.
TABLE-US-00007 TABLE 7 phase 1 phase 2 phase 3 phase 4 phase detection area NE SW NE SW WN ES WN ES moving S.fwdarw.N N.fwdarw.S N.fwdarw.E S.fwdarw.W E.fwdarw.W W.fwdarw.E W.fwdarw.N E.fwdarw.S direction (going- (going- (turn (turn (going- (going- (turn (turn straight) straight) left) left) straight)) straight) left) left) green signal ON ON OFF OFF ON ON OFF OFF extended (1) (1) (0) (0) (1) (1) (0) (0) application mode
[0116] Such an example of signal control is described for each traffic state in detail with reference to the drawings.
[0117]
[0118] First, when a specific phase starts, the controller turns off the entire end-possible mode of a corresponding phase green time movement (S101)
[0119] Furthermore, the controller determines a signal output from a preset detection area in a phase direction and determines a traffic state for each green time movement. When the spillback-possible state (β state) is generated in each green time movement (S102), the controller executes a process of controlling a signal in the spillback-possible state (β state) (S103). When the no-vehicle movement state (γ state) is generated (S104), the controller executes a process of controlling a signal in the no-vehicle movement state (γ state) (S105).
[0120] When the phase end near time (PENT) is reached without the generation of the β state or the γ state (S106), the controller executes a process of controlling a signal capable of terminating the normal state (α state) (S106).
[0121] When the process is finished, a next phase proceeds.
[0122] Furthermore, a case where a traffic state is the spillback-possible state (β state) is described below.
[0123] In
[0124] As described above, after the red signal is turned on, the controller determines whether the present time exceeds the residual green time criteria (RGTC) or not (S203). If the present time does not exceed the residual green time criteria (RGTC), when the traffic state becomes the no-vehicle movement state (γ state) in the detection area of the corresponding A green time movement (S204), the controller turns on a green signal again in the A green time movement (S205).
[0125] In this state, the controller determines whether the phase end near time (PENT) has been reached (S206). If the phase end near time (PENT) has been reached while the present lighting state is maintained before the phase end near time (PENT), the controller determines whether the green signal extension application mode of the present A green time movement is an “ON” state (S207). If the green signal extension application mode is the “ON” state, the controller determines whether the green time movement maintains the normal state (α state) (S208). If the green time movement is the normal state, the controller extends a green signal by the unit green (UG) (S209). The controller determines whether such extension has reached the extension limit green (ELG) (S210). If the extension has not reached the extension limit green (ELG), the controller repeatedly extends the green signal by the unit green (UG) plural times by repeating steps S208˜210. In this process, if the traffic state is determined to be not the normal state (α state) before the extension limit green (ELG) is reached at step S208 or the traffic state is determined to have reached the extension limit green (ELG) at step S210, the controller turns on the end-possible mode of the corresponding green time movement (S211).
[0126] Meanwhile, when the state (γ state) in which there is no vehicle in the A green time movement is reached after passing through the residual green time criteria (RGTC) at step S203 (S212), the controller switches to step S206 of the process.
[0127] Furthermore, if the traffic state is not the state (γ state) in which there is no vehicle in the A green time movement at step S212, the controller determines whether the traffic state is the phase end near time (PENT) or less (S213). If the traffic state is the phase end near time (PENT) or less, the controller repeats steps S212 and 213. If the traffic state becomes the phase end near time (PENT), the controller determines whether the traffic state is the state (γ state) in which there is no vehicle in the A green time movement (S214). If the traffic state is the state (γ state) in which there is no vehicle in the A green time movement, the controller switches to step S211 of the process. If the traffic state is not the state (γ state) in which there is no vehicle in the A green time movement, the controller extends a red signal by the unit red (UR) (S215) and determines whether the extension limit red (ELR) has been reached (S216). If the extension limit red (ELR) has been reached, the controllers switches to step S211 of the process. If the extension limit red (ELR) has not been reached, the controller repeats steps S214 to S216.
[0128] Furthermore, after the controller turns on the end-possible mode of the A green time movement at step S211, it determines whether the end-possible mode of the B green time movement is ON (S217). If the end-possible mode of the B green time movement is ON, the controller terminates the phase (S218).
[0129] Furthermore, signal control when the no-vehicle movement state (γ state) is generated is described with reference to
[0130] The controller determines whether the no-vehicle movement state (γ state) has occurred in the present green time movement by determining a traffic state based on a signal output from a preset detection area in response to the green time movement. If the no-vehicle movement state (γ state) has occurred, the controller sets the corresponding green time movement as an A green time movement and sets another green time movement as a B green time movement (S301).
[0131] Furthermore, the controller determines whether the crosswalk of the A green time movement is a green lighting state (S302). If the crosswalk is the green lighting state, the controller maintains the corresponding signal lighting state. If the crosswalk is not the green lighting state, the controllers turns on a red signal after a yellow signal with respect to the corresponding A green time movement (S303).
[0132] Thereafter, the controller turns on the end-possible mode of the corresponding A green time movement (S304) and determines whether the end-possible mode of the B green time movement is ON (S305). If the end-possible mode of the B green time movement is ON, the controller terminates the phase (S306).
[0133] If the end-possible mode of the B green time movement is not ON at step S305, however, the controller determines whether the green signal of the B green time movement is earlier than the residual green time criteria (RGTC) (S307). If the green signal of the B green time movement is earlier than the residual green time criteria (RGTC), the controller returns to step S305 of the process. If the green signal of the B green time movement exceeds the green time criteria (RGTC), the controller turns on an alternative movement of the A green time movement, that is, a green time movement in the γ state, in green (S308), turns off the end-possible mode of the A green time movement (S309), and sets the alternative movement of the A green time movement as the A green time movement (S310).
[0134] The controller determines whether the traffic state is the γ state with respect to the A green time movement that has been newly set as the alternative movement of the A green time movement as described above (S311). If the traffic state of the A green time movement is the γ state, the controller turns on the end-possible mode of the corresponding A green time movement (S312) and determines whether the end-possible mode of the B green time movement is ON (S313). If the end-possible mode of the B green time movement is ON, the controller terminates the phase (S306). If the end-possible mode of the B green time movement is not ON, the controller returns to the process of step S311.
[0135] Furthermore, if the traffic state of the A green time movement is not the γ state at step S311, the controller determines whether the phase end near time (PENT) has been reached (S314). If the phase end near time (PENT) has not been reached, the controller returns to step S311 of the process. If the phase end near time (PENT) has been reached, the controller determines whether the extension mode of the A green time movement is ON (S315). If the extension mode of the A green time movement is not ON, the controller returns to step S312 of the process. If the extension mode of the A green time movement is ON, the controller determines whether the A green time movement is the α state (S316). If the A green time movement is not the α state, the controller returns to step S312 of the process. If the A green time movement is the α state, the controller extends the green time by the unit green (UG) once or several times (S317) and determines whether the green time has reached the range of a preset extension limit green (ELG) (S318). If the green time has not reached the preset extension limit green (ELG), the controller returns to step S316 of the process. If the green time has reached the preset extension limit green (ELG), the controller returns to step S312 of the process.
[0136] Furthermore, signal control when the normal state (α state) may be terminated is described with reference to
[0137] If a green time movement does not correspond to the γ state or the β state in a corresponding phase and approaches the end of the phase in the normal state (α state), when the normal state (α state) is maintained in the phase end near time (PENT), the controller sets the a state green time movement as an A green time movement and sets another green time movement as a B green time movement. In this process, if all of a plurality of green time movements are the α state, the controller sets any one of the plurality of green time movements as the A green time movement and sets the remaining green time movements as the B green time movement (S401).
[0138] Thereafter, the controller determines whether the extension mode of the A green time movement is ON (S402). If the extension mode of the A green time movement is not ON, the controller turns on the end-possible mode of the A green time movement (S403). If the extension mode of the A green time movement is ON, the controller extends a green signal by the unit green (UG) (S404) and determines whether the corresponding A green time movement is the α state (S405). If the A green time movement is not the α state, the controller switches to step S403 of the process. If the A green time movement is the α state, the controller determines whether the green time has reached the extension limit green (ELG) (S406). If the green time has not reached the extension limit green (ELG), the controller returns to step S404 of the process and extends the green time up to the extension limit green (ELG).
[0139] Furthermore, when the green time reaches the extension limit green (ELG), the controller turns on the end-possible mode of the A green time movement (S403) and determines whether the end-possible mode of the B green time movement is ON (S407). If the end-possible mode of the B green time movement is ON, the controller terminates the phase (S408).
[0140] In the present invention, as described above, a detection area is set within an intersection, the traffic state of a green time movement is determined based on the occupied time information of a detected vehicle, and an intersection signal is automatically controlled depending on the traffic state.
[0141] In addition, a method of disposing a detection area in a street section outside an intersection and performing signal control in a special case has been invented. This method is described using
[0142]
[0143] The entry detection areas and the entry/exit detection areas set in the entry areas and exit areas, respectively, are set so that a carriageway in which a right-turn pass is present in the four-way signal intersection is not detected, set so that a going-straight carriageway and a left-turn carriageway are separated, and set so that they are spaced apart at specific interval in an intersection entry area or exit area. Table 8 shows an entry area and entry/exit detection area for each green time movement in a separation signal. Table 9 shows an entry area and entry/exit detection area for each green time movement in a simultaneous signal. In Table 8 and
TABLE-US-00008 TABLE 8 1 Phase (φ1) 2 Phase (φ2) 3 Phase (φ3) 4 Phase (φ4) detection detection detection detection moving area moving area moving area moving area direction entry Inner exit direction entry Inner exit direction entry Inner exit direction entry Inner exit {circle around (1)} SR NE NL {circle around (6)} NR NE EL {circle around (7)} WR ES EL {circle around (4)} ER ES SL {circle around (5)} NR SW SL {circle around (2)} SR SW WL {circle around (3)} ER WN WL {circle around (8)} WR WN NL
TABLE-US-00009 TABLE 9 1 Phase (φ1) 2 Phase (φ2) 3 Phase (φ3) 4 Phase (φ4) detection detection detection detection moving area moving area moving area moving area direction entry Inner exit direction entry Inner exit direction entry Inner exit direction entry Inner exit {circle around (1)} SR NE NL {circle around (3)} ER WN WL {circle around (5)} NR SW SL {circle around (7)} WR ES EL {circle around (2)} SR SW WL {circle around (4)} ER ES SL {circle around (6)} NR NE EL {circle around (8)} WR WN NL
[0144] Basically, signal control is performed based on detection area information within an intersection, but is performed if entry detection area information is the no-vehicle movement state (γ state) in all of the directions or entry/exit detection area information in a green time movement is the spillback-possible state (β state).
[0145]
[0146] First, the controller performs signal control according to a phase sequence recorded on the memory and a phase time (S501). If pass information in the entry detection areas in all of the directions is the no-vehicle movement state (γ state) (S502), the controller turns on a red or yellow signal in all of the directions in a flickering manner (S503). Thereafter, when pass information in the entry detection area in one or more carriageways becomes the normal state (α state) (S504), the controller returns to the original phase operation.
[0147] Furthermore, a signal transmitted from the entry detection area is determined. If entry/exit detection area information in a green time movement is the spillback-possible state (β state), signal control is performed as in the case where information in the spillback-possible state (β state) is transmitted in the detection area within the intersection.
[0148] If green time information for each phase that has been actually changed and applied in a specific time zone for a specific period in an intersection to which the present invention has been applied is stored and a mean value, etc. is calculated and used as the initial value of a phase length, a more efficient signal operation can be performed.
[0149] In the present invention, a detection area is set within a signal intersection, a vehicle that passes through the intersection is determined and detected for each green time movement, a traffic state is determined and analyzed based on the detected information (an occupied time, etc.), and a signal is automatically controlled for each green time movement in a phase according to the traffic state. Accordingly, a spillback phenomenon in an intersection can be prevented, a green time (green lighting time) when there is no vehicle can be minimized, and the green time may be extended, if necessary, to enable smooth traffic easy-going.
[0150] The present invention described as above is not limited to the embodiments and the accompanying drawings and may be substituted, modified, and changed in various ways without departing from the technological spirit of the present invention, which are evident to a person having ordinary skill in the art to which the present invention pertains.