Traffic Signal Developments

TrainSignal revelopments.

NO motorist likes unnecessary delay in the way of traffic hold-ups, but what exasperates him most of all is ” standing by” for a red light to change, via amber, to green, and so permit him to cross a road junction which has been devoid of traffic for the whole time he has been waiting. This is the drawback of the ” fixed, time” traffic control signal, which in spite of its advantages, cannot adjust itself to the volume of traffic in any given direction.

The latest development is a signalling System which is automatically controlled by the traffic itself, and has very special advantages in the case of an intersection between an arterial road and a minor road, crossing it. The signal itself is the normal red,, yellow, and, green, but it is operated by means of contact plates let into the surface of the minor road a short distance from the main road, and operated, by the approaching car. Contrary to present practice, the signal on the main road is normally at green, and, remains so until a car approaches

from the side road. This car passes over the plate and in so doing changes the main road. signal to red, the side road signal being at red when the car arrives. From then everything is operated automatically by condenser-controlled time switches, and after an interval suitable for the main road traffic to obey the red light, the side road, car receives the green signal and proceeds across the main road. After a specified interval the lights change back again and, the main road fast traffic proceeds. A succession of cars from the side road will not hold up the main traffic indefinitely as there is an automatic control which stops the green showing to the side road for more than a definite time. If sufficient traffic appears from both roads the device becomes similar in its time of operation to the fixed time signals at present in. use, 80 that it is perfectly suited, for town work, and is used as such all over the U.S.A. If a car turns off the arterial road to go down the sid,e road, and happens to run over the plate from the wrong direction nothing happens, as the switch is so arranged that it can only

b2 operated from one side, being hinged in the middle.

Bodywork Construction.

THE thousands of people who saw the Lord Mayor’s Show liz London last month, would be surprised to learn that many modern motorcars are still built in very much the same way as the Lord Mayor’s ornate coach.

The old coa,chbuilding ideas of a bulky wood, frame, heavy and splinterable, with a cumbersome wooden sill to hold it down to the steel chassis are still used by some manufacturers.

Now, however, with the growing popularity of the one-piece steel body, new methods are coming into use. This form of body, which is produced in the Pressed Steel Company’s works at Oxford, makes body and chassis into one. The pressed steel body consists of four main units welded together and fixed direct to the chassis. With no intermediate wood frame between body and. chassis, the whole car is lighter and, at the same time, stronger, and, greater stability is assured by the lowered centre of gravity.