ROAD TRAFFIC CONTROL SYSTEM

• US 3,660,812 A
• Filed: 05/01/1970
• Issued: 05/02/1972
• Est. Priority Date: 05/01/1970
• Status: Expired due to Term

• Current Assignee: Hiroshi Inose, Hiroya Fujisaki, Takashi Hamada
• Original Assignee: Hiroshi Inose, Hiroya Fujisaki, Takashi Hamada
• Inventors: Inose, Hiroshi, Fujisaki, Hiroya, Hamada, Takashi
• Primary Examiner(s): Cooper, William C.
• Application Number:
  US05/033,826
• Time in Patent Office: 732 Days
• Field of Search: 340/35
• US Class Current: 340/911
• CPC Class Codes: G06G 7/76 for traffic
• CPC Class Codes: G08G 1/081 Plural intersections under common control

Abstract

This invention provides an apparatus for effecting optimal road traffic control of a road network in a traffic area, such a traffic area being divided into a plurality of sub-areas and a district controller being provided in each sub-area. The district controller is provided to control the traffic in the sub-area, road network, establishing a preferential offset for two-way traffic for a tree pattern of the road network which includes no closed road loop, by considering the offset effect quantum for each road section between signals, and a split for each intersection and a common cycle length thereby minimizing the delay time in the sub-area as based on information from traffic detectors on the road and other road conditions. A Central Controller is provided for controlling traffic of the entire road network in the area by coordinating the district controllers as based upon the traffic pattern of the entire area.

Claims

1. A traffic signal control system for a district having a complex road network pattern, including a plurality of traffic detectors each output of which is processed by traffic counting means for producing information indicative of traffic flow in a selected road network, cycle selecting means responsive to said information to select an optimal traffic signal cycle length for the road network, and split selecting means responsive to said information to determine the traffic signal split value of each intersection in the road network, characterized by offset selecting means for determining an optimal tree pattern of said road network in response to said traffic flow information and assigning an optimal offset to each road section included in said tree.

2. The traffic signal control system in accordance with claim 1, wherein said offset selecting means determines the optimal tree on the basis of on-line computing by a gate network which has the same pattern as the road network and assigns the preferential or balanced offset to each road section included in the determined tree.

3. The traffic signal control system in accordance with claim 1, wherein said offset selecting means selects the optimal tree from a plurality of tree patterns predetermined in accordance with the standardized traffic patterns of the road network and assigns the preferential or balanced offset to each road section included in the selected tree.

4. A traffic control system for a large scale area which is divided into a plurality of districts each of which is controlled by a district controller in accordance with claim 1 characterized in that the control system includes a central controller including a traffic pattern detector which receives the traffic information transmitted from the district controllers to determine the traffic flow pattern of the area and a switching network which, responding to the flow pattern, selects at least one tree pattern of the area fRom predetermined sets of tree patterns and coordinates the district controllers of each district belonging to each selected tree pattern by assigning a cycle value common to each group of districts included in a tree pattern and assigning optimal offset values to road sections which connect the adjacent districts.

5. A road traffic control system for the regulation of vehicular traffic flow in a district having a plurality of joined road sections with each having signalized intersections at both ends, comprising traffic flow detection means operable to produce traffic flow information representative of the traffic flow on each road section;

a district controller device connected to receive said traffic flow information for the determination therefrom of cooperative values of the cycle, split and relative offset for each traffic signal at said signalized intersection to provide optimal traffic flow in said district;

said district controller including a traffic counting device operable to determine and produce from said traffic flow information traffic volume and density output information for each of said road sections, a cycle selection circuit operable to determine and produce compatible cycle duration information with the use of said output information for each traffic control signal at said intersections, a split determination circuit operable to determine and produce compatible split information with the use of said output information for each traffic control signal at said intersections, and an offset determination circuit operable to determine, produce and assign optimal offset value information with the use of said output information for each traffic control signal at said intersections;

local controller means connected to receive said cycle, split and offset information and operatively connected to said traffic control signals to cooperatively actuate them in accordance with said cycle, split and offset information to provide optimal traffic flow in said district;

said offset determination circuit including an offset effect circuit receiving said output information and operable to calculate and produce therewith offset effect quantum information representative of the offset effect for each road section, tree selection circuit means connected to receive said offset effect quantum information and operable to successively select the offset effect information having the largest value and rejecting offset effect information values which represent road sections that would form a closed loop with those road sections of previously selected higher offset effect signal values until all of said road sections have been accordingly covered such that a connected road section optimal tree pattern without closed loops is selected, and an offset selection circuit connected to said tree selection circuit to select and assign said cooperative optimal offset information for each road section included in said tree.

6. The road traffic control system of claim 5 wherein said tree selection circuit comprises a gate network which has the same pattern as the road network and selects said tree by on-line computing.

7. The road traffic control system of claim 5 wherein said tree selection circuit comprises means to select the optimal tree from a plurality of tree patterns predetermined in accordance with the standardized traffic patterns of the road network.

8. The road traffic control system of claim 5 which includes a large traffic control area for control which is divided into a plurality of districts each of which is controlled by a district controller in accordance with claim 5, characterized in that the control system includes a central controller including a traffic pattern detector which receives said output information transmitted from the district controllers to determine the traffic flow pattern of the area and a switching network which, responding to the flow pattern, selects at least one tree pattern of the area from predetermined sets of tree patterns and coordinates The district controllers of each district belonging to each selected tree pattern by assigning a cycle value common to each group of districts included in a tree pattern and assigning optimal offset values to road sections which connect adjacent districts.

9. In a road traffic control system for the regulation of vehicular traffic flow in a district having a plurality of road sections with each having signalized intersections at both ends, a traffic signal offset determination circuit comprising, offset effect circuit means to calculate the values of offset effect for all of said road sections, tree selection circuit means connected to receive the output of said offset effect circuit means to successively select the road sections having the largest offset effect value and reject those road sections which would form a closed loop with previously selected road sections of higher offset effect value until all of said road sections have been accordingly considered such that a connected optimal road section tree pattern is selected without closed loops, offset selection circuit means connected to said tree selection circuit means to produce and assign cooperative optimal offset values to the traffic signals controlling the road sections forming said tree such that the vehicular travel delay time therealong in both directions is minimized.