Traffic lights, David Mellor, 1965

21 September 2022

MoDiP recently visited the Yunex Traffic manufacturing facility in Poole to talk about traffic lights. The company supply, install and maintain traffic signal and control equipment for the BCP council, and had kindly offered to donate some plastics objects to the museum.

We were treated to a tour of the factory where we got to see examples of some of the 20,000 different variants of traffic light signal heads being produced for customers across Europe. The image below shows a green coloured signal head in polycarbonate, destined for Germany and looking very different to the styles we commonly see on UK roads.


A German signal head.
Image credit: Katherine Pell

We were then shown the repair centre where parts can be re-used from old stock. For example, if a junction has been updated and new signal heads installed, the old lights will be brought here. Anything that cannot be rotated ends up in the waste collection area to be recycled (refer image below).


The waste collection area.
Image credit: Katherine Pell

It was here that we were able to acquire a few new items for the collection, since our objects do not have to be in working order. Our host, Kelvin Shergold, had very kindly managed to secure us a David Mellor signal head from Somerset (Yunex Traffic maintain contracts with lots of different councils), which was the main reason behind our first contacting the company (refer image below).


Kelvin holding the Mellor signal head (left) and close-up detail (right).
Image credit: Katherine Pell

David Mellor was commissioned by the Ministry of Transport to standardise the design of traffic lights in the UK in 1965. Updating a system that had been relatively unchanged since the 1930s, the project was in response to a 1963 report that concluded existing traffic management to be out of date for both the increased numbers of vehicles on the road and their increased speed. The new signal head required improved visibility, had to be adaptable to include additional signage such as filter arrows where necessary, and needed to provide more assistance for pedestrians crossing the road.


Original drawings (left) and the new signals on trial in London (right).
Image credit:

The Mellor signal head was introduced in 1968, with the individual lights encased within a blow moulded unit in polypropylene (PP). Two flat panels in polyethylene (PE) were screwed on either side to make the overall body much larger, outlined in polyvinyl chloride (PVC) reflective tape, and easily replaceable with different panels that incorporated a variety of regulating signs. Each light had a hinged opening at the front to access the bulb (whereas previously the fitting would need to be unscrewed), and large protruding, flexible, impact resistant visors in PE covered the new lamps to prevent natural light reducing contrast. The new signals were maintenance-free, with all components made of plastics materials, including the coating on the steel mounting poles.


A Mellor signal head in-situ, on the main road in front of the University.
The only other Mellor head I have spotted locally is at Winton Banks.
Image credit: Katherine Pell

Several manufacturers were employed to produce this design throughout the 1960s-1990s (MoDiP’s example was made by Plessey Automation) before it was superseded. Yunex Traffic kindly donated a more modern traffic light signal head too (refer image below): a Siemens Helios modular design that contains all the internal componentry within one box that opens via two sliding clips at the front, thereby simplifying the process of installation and fault repair. The boxes are clipped together and holes in the mouldings provide passage routes for cabling.


The Siemens Helios modular design.
Image credit: Katherine Pell

We also came away with a puffin crossing unit complete with a tactile cone. This small piece of polypropylene (PP) extends out underneath the push button and is there to assist those with visual impairment and/or partial hearing to cross the road safely. When the light changes to green, the ridged cone rotates alerting the user. An amazing plastics design, it was invented by traffic engineer Richard Keith Duley in 1987 and was manufactured by Radix, a company he co-founded with Milan Fuchs the following year.


A tactile cone in-situ, beneath the Mellor signal head in Wallisdown Road.
Image credit: Katherine Pell

We would like to say a very big thank-you to Kelvin and Yunex Traffic for their generosity and also to my daughter Millie, who first told me about tactile cones. 

All of these objects are now available to view in the museum, on request.


Katherine Pell
Collections Officer