In message , at
00:16:32 on Tue, 29 Nov 2005, Richard J.
remarked:

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

But the guidelines do say that for lit stretches of 600m or more, the
first and last repeaters should be not more than 450m from the
start/end of the lit section, so it would be reasonable to expect at
least one repeater in a lit section of more than 450m.

Yes, if the lit section is more than 600m. Especially if you are new
to the area, you may not know how far the lights go.

No, what I mean is that it would be reasonable to apply the "first
repeater within 450m" rule for lit sections of between 450 and 600m as
well as for those of 600m.

I'm not sure that a repeater 450 yards into a 500 yard lit section is
every helpful. What's really needed is a repeater at the *first*
lamp-post. I have no idea why this rather simple thing isn't part of the
recommendations.

However, the guidance is poor in my view. I much prefer the French
practice of often putting several repeater signs close together just
after the start of the limit, which leaves you in no doubt what the
limit is. In Britain, if you miss the initial sign,

Which initial sign is that? We are mainly talking about isolated
stretches of lit road (whether they be thorough a village, or merely
adjacent to a junction) where there's no sign at the start of the lit
section.

In which case the previous limit still applies.

No, and this is the whole point. Where there are lights the previous
limit is irrelevant, and the limit is automatically 30mph. *Except* for
very short lit sections, and except when there are repeaters. But
because you don't encounter the repeaters immediately, nor do you
encounter the other end of the lit section immediately (so can't tell if
it's "very short" or not), there is always a doubt about what the limit
is until you've surveyed the stretch in advance.

Where the limit changes, they should sign it properly,

"Properly" seems to be defined by these recommendations about "450m"
etc. I agree that it seems inadequate.

and it stays in force until the next limit change. If there's likely
to be any doubt, put in extra repeaters as necessary. But all this
stuff about street lights and whether they are close enough together is
not helpful. (I mean the DfT rules are unhelpful, not your discussion
of them.)

And another thing. How is the 200yds measured? Is it literally from lamp
standard to lamp standard (which may be on alternate sides of the road)
or is it measured along the middle of the road between perpendiculars to
each lamp?

It's led to ludicrous rules like it being illegal to put up 30mph
repeaters in a lit street unless there is a speed camera within 1km.

That's interesting. I've seen some villages in Essex with 30mph
repeaters. I always thought that was because Essex took a different view
on where they could be installed. I will look a bit closer at the lamp
spacing next time, and see if the roads aren't in fact "lit" officially.
There are no speed cameras.
--
Roland Perry