In message , at 17:50:32 on
Mon, 28 Nov 2005, Dr Ivan D. Reid remarked:
ps Does anyone have a link to the current version of the document where
things like the "500m" above are defined?

"You MUST NOT exceed the maximum speed limits for the road and for your
vehicle (see the table below). Street lights usually mean that there is
a 30 mph speed limit unless there are signs showing another limit.

The ABD page: http://www.abd.org.uk/speed_limit_signs.htm provided
elsewhere in this thread has the distances to which I refer. It's quite
complex, and also mentions the "200 yds" distance which makes a street
officially "lit".

Assuming that it's not almost entirely written with cul-de-sacs in mind,
I assume that when they refer to (eg) "Lit road more than 600m in length
on which the national speed limit applies" that what they really mean is
"Road with more than 600m of it lit ..."

So there is the possibility of stretches of 599m of lit road where the
limit is still NSL, without any repeaters being required. [1].

Which brings me back to my original question: If there is a lit
roundabout (say 100m across) with 500m of lighting on each of two of the
approach roads, is that 1.1km of lit road [therefore requiring
repeaters], or three separate stretches of road of 500m, 100m & 500m,
not requiring repeaters.

[1] And if somehow you know it's longer than that, it could be 250m
before you can tell by the absence of repeaters (either 40 or NSL), that
you should have been doing 30mph from the start.
--
Roland Perry