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Traffic Control Synchronization Between Groups of Intersections

IP.com Disclosure Number: IPCOM000073970D
Original Publication Date: 1971-Feb-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Babyak, J: AUTHOR [+3]

Abstract

Intersections along at least a portion of a main artery that are under computerized traffic control are usually grouped together in a "subset" and operate under common control. In a large metropolitan area, the number of subsets may be too large for control by a single computer. Thus, a supervisory computer with a plurality of subsidiary computers may be employed.

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Traffic Control Synchronization Between Groups of Intersections

Intersections along at least a portion of a main artery that are under computerized traffic control are usually grouped together in a "subset" and operate under common control. In a large metropolitan area, the number of subsets may be too large for control by a single computer. Thus, a supervisory computer with a plurality of subsidiary computers may be employed.

To provide synchronization across subset boundaries, providing cooperative control of traffic flow throughout the entire area, a special system organization is employed. The supervisory computer provides subset coordination across subsidiary computer boundaries for selected subsets by including these subsets in a "group." All intersections that are members of the group always operate on a common "cycle length." "Cycle length" is defined as the length of time for the signals at an intersection to complete a full cycle. Thus, when a subsidiary computer notes that the traffic in a subset has changed sufficiently to require a change in the control pattern for that subset, it first notifies the supervisory computer. The supervisory computer then determines a cycle length for the entire group by an averaging calculation. It then determines the "offset," defined as the time difference between the beginning of the main street green on different intersections, for each subset in the group to go with the new patterns for these subsets. This informati...