New Traffic Lights " Think "
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THE new system of traffic light signals in Oxford Street, London, installed at •a cost of 07,000, was formally brought into operation on Monday by Mr. John Boyd-Carpenter, Minister of Transport.
These signals replace the old fixedtime signals installed nearly 25 years ago. The changeover from the old system to the new has been carried out gradually. Under the old system, the signals changed at fixed intervals, worked by a clock motor. These intervals were set to meet average traffic needs, but the system took no account of the variations in traffic from minute to minute.
The new system takes advantage of any momentary casing of traffic, and is self-adjusting to meet traffic needs from moment to moment. There are two master controllers working on alternate days but arranged so that if one fails the other immediately takes .over, The master controller Mints all vehicles arriving at Oxford Circus and every five minutes assesses the situation. It also takes account of the time of day and day of the week.
On the basis'of these calculations, the master controller can do a 'variety of things. For example, it can cut out some side-roads detectors to give a bias in favour of the main road; or when traffic is light, as at night, it can leave each individual controller at the various junctions to work independently.