CONTROL OF TRAFFIC.

New Zealand Herald, Volume LXVIII, Issue 20969, 4 September 1931, Page 16

CONTROL OF TRAFFIC.

AUTOMATIC SYSTEM. EXPERIMENTS IN SYDNEY. [FROM OTTB OWN CORREBPONDBNT.] SYDNEY, August 37. With a view to reducing the cost o? traffic supervision, the traffic authorities in Sydney will shortly experiment with mechanical systems of control. It is not thought likely that mechanical control will entirely displace traffic police on point duty, as the characteristics of the flow of traffic at many points of the city vary at irregular intervals of the day. Mechanical systems have not yet been designed to meet these conditions. Preliminary investigations have indicated that control of the city traffic probably would be effected most satisfactorily by mechanical signalling at points where the flow of traffic is fairly regular, by traffic police at the more difficult points, and possibly by an extension of the existing system of tramway flagmen. The system of mechanical control in operation in Melbourne may be experimented with here. Melbourne's traffic ! lias been controlled by mechanical signals for about two years. At all the busy intersections signals with lights show "Stop" on red glass, "Caution"- on amber, and "Go" on green. All traffic that has not already started to cross intersections must stop when the "caution" light shows. It remains on just long enough for the tail end of the traffic to get away, and leave the way clear for cross traffic. In a street with cross streets at regular intervals, the traffic lights synchronise in such a manner that a motor-car travelling at about 15 miles an hour will get an uninterrupted run through that street. Right-hand turns are forbidden in poak periods. In quieter periods right-hand turns are made by closing into the left at tho intersection, and then waiting for the "stop" signal against traffic flowing behind. After the "caution" signal tho "go" signal opens up the route for tho cross traffic, and the driver joins in. At peak periods it is necessary to drive until one is clear of traffic signalg, and then turn round and come back to the intersection, and make a left-hand turn. The "stop" and "go" signals show alternatively at each intersection for about 60 seconds. Between tho change-over the "caution" light shows for about 15 seconds.