GB472832A - Improvements in or relating to traffic control systems - Google Patents

Abstract

472,832. Road signals for controlling traffic. AUTOMATIC ELECTRIC CO., Ltd., RENSHAW, A. P. B., and THOMPSON, G. W. March 30, 1936, No. 9394. [Class 118 (ii)] In a system in which signals at a number of adjacent intersections are fully vehiclecontrolled, a vehicle passing one intersection controls the transmission of a signal to an adjacent intersection which ensures that, if right of way is with the main road, the normal maximum timer recommences to measure the maximum period after a given time period, this time period being adjusted to allow green wave signalling along the main road. The invention is described as applied to three intersections X, Y and Z, Fig. 3, the equipment at intersection Y being indicated in Figs. 1 and 2, and the interconnecting equipment being shown in Fig 4. The apparatus at each intersection comprises the normal timer FA, A, QA controlled over resistance AR to time the initial and vehicle intervals and the amber period, a maximum timer B, FB, QB and an additional timer C, FC, QC. In ordinary practice the apparatus at Y is controlled by pads DB, Fig. 2, in the side streets and by pads band e, Fig. 3, which energize relays O and P, Fig. 4, to control relay E, Fig. 2, If an approaching vehicle crosses pad a and the right of way is with the cross-street, relay 10, Fig. 4, is energized and locks relay 1RA (not shown), being operated in parallel with the red lamp similarly to relay RA, Fig. 1, at Y. When the signals change to amber, relay 1AA (not shown), pulls up and contacts Q, R are bridged to energize relay E, Fig. 2, and relay OR, Fig. 4. If the right of way at Y is with the crossstreet, relay E initiates transfer to the mainroad in the normal way. Relay OR connects up the timer C, FC, QC, which is adjusted to take the same time as a vehicle travelling at a normal speed takes to travel from pad a to pad b. At the end of this period relay C operates and relay MR pulls up to release OR. If, at Y, right of way is with the main road, so that relays AA and RA are both back, relay M also energizes and locks so that the maximum timer is connected over switch MA. At the same time relay C discharges condenser QB so that the maximum timer recommences to measure the maximum period. The release of relay OR releases relay C and discharges condenser QC. If contacts 10 and 11, Fig. 2, are joined as indicated, the relay M is energized when C pulls up irrespective of whether right of way is with the main or cross-streets, and this may help to bring the units at the crossings into synchronism more quickly. If vehicles are approaching over pad d, the operation is similar, the control being through relay PR and switch PD2. The pads at intersection Y exert similar control on the apparatus at intersections X and Z. Specifications 403,732 and 446,288 are referred to.