On Nov 29, 7:52*pm, "Richard J." wrote:
Neil Williams wrote:
On Sat, 29 Nov 2008 14:14:37 -0000, wrote:


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 athttp://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)

The original purpose of the boards was to provide a background against
which the signal stood out. When viewed against the sky it was often
difficult to see which aspect was illuminated, together with
increasing street clutter. The boards started being dispensed with in
London when new signal heads were introduced that were much brighter
during the day (and even LEDs in some cases) and adjusted to be less
bright at night. The boards, which were always a maintenance
nightmare, coming loose or being hit by vehicles, were considered
unnecessary in view of the increased visibilty of the new aspects.

Maybe London has more of these lights than elsewhere in the country,
so the boards are still more prevalent outside the Capital.

Peter