In article ,
(Richard J.) wrote:

Neil Williams wrote:
On Sat, 29 Nov 2008 14:14:37 -0000, wrote:

I see. I was just wondering if it meant that some could be manually
controlled, while others were completely on time automation.

A lot more lights have them outside London than in it. Why has London
always been different? (Other than that a narrow bodied traffic light
with no border has always had a very distinctive London look to me).

Before 1965, all posts carrying road signs were painted in
alternating black and white bands. On traffic lights, the black
and white stripes extended to the light units themselves, the red
and green units were black and the amber unit was white. When the
new road signs were introduced in 1965, all posts became grey, and
I think it was then that the black backing board and thick white
border were introduced. I assume that it wasn't necessary to
retrofit the boards to old traffic lights.
(Illustration at http://www.igg.org.uk/gansg/00-app1/tlight.jpg )

Probably London's roads were more densely populated with traffic
lights than the rest of the country, and hence (I'm guessing here)
for some years the majority of new traffic lights were installed
outside London. But the boards made the whole assembly much wider
than previously, and caused problems at constricted sites. Hence
the boards are now optional, as are the white borders.

I don't think back boards go back anywhere near 1965. They came in no
earlier than the 1980s IIRC.

--
Colin Rosenstiel