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.
--
Richard J.
(to email me, swap 'uk' and 'yon' in address)