Traffic Lights – Proceed with Caution

Proceed with Caution

Memory plays tricks. It was unnerving that I thought that I remembered something and could find no confirmation. It was about traffic lights.

I remember traffic lights used to have the word “STOP” in black letters on the red light lens. In my home town, there was also one old green traffic light lens on which was etched “GO” in black letters. So when my father passed his test and we went to Blackpool in his newly acquired Triumph, we met the traffic lights in Preston.

This was long before the new roads were built around Preston in the 1960s.

So it was at the junction of Deepdale Road and Blackpool Road that I discovered that the amber traffic light lens was etched with the word “CAUTION” in black letters.

Those lenses stayed there until about 1970. Although there are lots of references on the web to traffic lights, no reference did I find to “CAUTION” being shown on the amber (or yellow) lens and I had begun to think that I had imagined this until I found this report today from the Yorkshire Evening Post for 1928:


Friday 16 March 1928 – “THE ALL-ELECTRIC POLICEMAN. CONTROL OF TRAFFIC. New Device Tries Out at Busy Corner.

“The occupation of the traffic policeman is threatened by an electrical automatic traffic signal installation, which began operations at the corner of Park Row and Bond Street, Leeds, to-day. This is the first installation of its kind in Great Britain. Leeds, therefore, leads again, but Edinburgh will follow closely, as a similar apparatus is to be tried out in the Scottish capital on Monday.

“The trial was an eminently successful one. Up to the time of its beginning, the usual burly figure of the policeman stood in the centre of the four roads…at the appointed minute the policeman stopped all four streams of traffic and retreated to the footpath. The electrical device came into instant operation.

“The scheme is simplicity itself. At each left-hand corner is a standard showing three discs. The top one is red and displays, when illuminated, the word “Stop”; below is a yellow disc proclaiming “Caution,” and at the bottom is one in green with the order “Go.”


“These face the oncoming traffic, and when the disc shows “Stop” the leading vehicle pulls up at a white line drawn across the road. When the red light goes out and the yellow one appears the driver “stands to the ready,” and advances immediately on the “Go.”

“The two streams are alternately reciprocal, the one preceding east or west while that bound north and south is at the stop, and vice versa.

“In the first instance, to-day, a trial was made with 18 seconds for the top and two seconds for the caution; it was then advanced to 23 seconds stop and two caution; but finally made 30 seconds stop.

“Drivers quickly appreciated the objects of the device and there was no confusion. Though identical times were employed for both streams of traffic in the experiment to-day, they will not necessarily remain so, but will be determined at this, and at any other spot where it is decided to install the apparatus by the relative importance of the two roadways.”

So there you have it. Traffic Lights proclaimed “STOP”; “CAUTION” and “GO” when they were first in use in England in 1928. Some of the early traffic lights were still about into the 1970s.

Also, as first used, the sequencing was different from that of today, in that all lights showed separately from Red to Green and from Green to Red and that the present sequence of RED/RED+AMBER/GREEN was not used until some time after traffic lights were more commonly installed.

Does this matter? Of course it does. It is only by finding the exhaustive details of the past that we can have a reasonable understanding of where we are today.

Proceed with Caution


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