STREET SIGNALS

Rotorua Morning Post, Volume 1, Issue 205, 22 April 1932, Page 7

STREET SIGNALS

AUTOMATIC SYSTEM IN OPERATION IN U.S.A. SPEED AND PROTECTION. A traffie signal automatically actuated has been evolved and is now in operation in certain cities in the United States. It enables the volume of traffie actually to be controlled by the interesection lights. The device consists of plates let into the street surface about 70 yards from the crossing. These plates are • sensitive to weight, and when a vehicle crosses them, electric impulses are transmitted to a relay, which co-ordinates the impulses from the several plates at an intersection and automatically sets the signal lights best to meet the conditions of traffie. By this means an approaching car can, when no croSs trafic has been electrically signalled to the automatic device, call on the "green" light instantly; and, at the same time, the signal ensures it protection from approaehing Cross traffie. The device can be adjusted to lim.it the flow of traffie in one direction for a given period. The design of the dispatcher unit is extremely sensitive, flexible, and accurate. In Boston (U.S.A.) careful studies showed that in a street earrying 1000 cars per hour the average delay with fixed lights was 110 car minutes per hour, or the equivalent of two cars constantly waiting to get through — whereas with the vehicle-actuated lights the approximate delay was only between 40 and 50 car minutes per mile.