In article , d
wrote:

On Fri, 30 Jul 2010 07:23:26 +0100
Charles Ellson wrote:
Did anyone believe it worked anyway? Why would anyone writing the software
make the cars lane part of the database key in the first place? It makes
no sense whatsoever.

Possibly for the sake of simplicity to allow for e.g. the difference
in speed between two vehicles remaining in parallel in lanes 1 and 4
where there is a significant curve between measurement points. If the
usual 10% etc. tolerance is ignored and speed limits applied strictly
then in theory it would be possible for the two vehicles to stay
together with one under and one over the speed limit.

In theory , but it would have to be one hell of a small radius curve to make
a significant difference. Not something you're likely to find on the sort
of roads these cameras are placed on.

No it wouldn't - the difference in distance only depends on the
difference in heading between the start and end points.

Sam

On 30/07/2010 16:03, Sam Wilson wrote:
In , d
wrote:

On Fri, 30 Jul 2010 07:23:26 +0100
Charles wrote:
Did anyone believe it worked anyway? Why would anyone writing the software
make the cars lane part of the database key in the first place? It makes
no sense whatsoever.

Possibly for the sake of simplicity to allow for e.g. the difference
in speed between two vehicles remaining in parallel in lanes 1 and 4
where there is a significant curve between measurement points. If the
usual 10% etc. tolerance is ignored and speed limits applied strictly
then in theory it would be possible for the two vehicles to stay
together with one under and one over the speed limit.

In theory , but it would have to be one hell of a small radius curve to make
a significant difference. Not something you're likely to find on the sort
of roads these cameras are placed on.

No it wouldn't - the difference in distance only depends on the
difference in heading between the start and end points.

The _absolute_ difference in distance (i.e. measured in metres) only
depends on the difference in heading between the start and end points
_and the radial distance between the midpoints of the two lanes in
question_.

However, the relative difference in distance (i.e. the percentage of the
total distance) depends on the total distance travelled. To get a
significant percentage difference in distance (and hence speed), the
change in heading must be done in a short distance, and this implies a
tight curve.
--
Jeremy Double {real address, include nospam}
Rail and transport photos at
http://www.flickr.com/photos/jmdoubl...7603834894248/

On 29/07/2010 16:11, Graeme wrote:
In
wrote:

gurgled happily, sounding much like
they were saying:

As the tolerances for speed cameras are not advertised, then it is
foolish to risk your license by driving past at any mph above the
posted limit.

ACPO's recommended +10%+2 notwithstanding...

ACPO also recommended upping the Motorway limit to 80mph, that was
ignored as well.

You don't understand the difference between recommending a change to
legislation (which requires political agreement) and recommending a
tolerance for enforcement (which doesn't)?

I do, I was just being sarcastic. They don't have much choice with the
tolerance, car speedometers are only legally required to be accurate within
10%.


I think that the 10% margin only applies to over indicating, not under
indicating.

G

On Jul 30, 12:05*pm, tony sayer wrote:
In article ,
scribeth thus

On Fri, 30 Jul 2010 11:05:56 +0100
Bruce wrote:
Of course the easiest way to 'defeat' the cameras is to stick to the
speed limit. *Boring, I know, but it also helps save fuel.

Actually the easiest way to defeat them is to drive a foreign registered
car of which there are plenty around. If road safety was really the concern
then they'd have traffic plods patrolling the road, not revenue raising
"safety" cameras.

Strangely enough Bruce is right.
Drive at anything under the appropriate speed limit and there is a nil
chance of prosecution.
An obvious thing to do really. And you do not break the law which is
good.

On Jul 30, 1:36*pm, wrote:
On Fri, 30 Jul 2010 13:02:34 +0100

Mark Robinson wrote:
wrote:

some sanctamonious do gooder

ITYM, "a concerned citizen who had observed somebody breaking the law".

Concerned about what exactly? That the biker could get away with speeding
and he couldn't?

Would I be a "sanctamonious do gooder" if I reported somebody breaking
in to your house?

Please do explain how the motocyclist was effecting or doing any harm
to anyone or any property or business. Though no doubt he deprived the
treasury of some tax , sorry fine, revenue. Oh cry me a river.

B2003

It doesn't matter what harm he was doing. Potential damage is of some
concern though. Breaking the law is always a concern. It's strange
that some people think they should have the right to choose which laws
they break.

In uk.railway Jeff twisted the electrons to say:
It doesn't matter what harm he was doing. Potential damage is of some
concern though. Breaking the law is always a concern. It's strange
that some people think they should have the right to choose which laws
they break.

It's not so much the "picking and choosing" that I object to ... It's
the fact that they chose to break a given law and then whine on about how
unfair it was that they got caught!
--
These opinions might not even be mine ...
Let alone connected with my employer ...

On Fri, 30 Jul 2010 18:41:40 +0100, wrote:
On Fri, 30 Jul 2010 11:05:56 +0100, Bruce
wrote:
Added to which, it has been widely reported (and confirmed by the
cameras' manufacturer) that drivers can defeat a SPECS camera by the
potentially unsafe practice of lane-hopping during the measured section
of road.

There are only ever two on the cantilever posts.
First time I saw one of those with what I guess is a trademark or
similar incorporated within the construction it reminded me of an
Edwardian Tram Standard


I have done some work for a firm that supplies these cameras,

Any chance you might bump into someone who might know what inspired
the design.


Funnily enough, that was the first question I asked, but no-one knew
the answer. The firm has expanded rapidly and most of the staff I met
have only been there a short time.

I really liked the posts when they were painted dark blue. I realise
they probably had to be painted yellow to comply with some regulation
or other, but I think they look far less elegant than they did in
blue.

On Fri, 30 Jul 2010 20:11:50 +0100, "Gavin.Hamilton"
wrote:

On 29/07/2010 16:11, Graeme wrote:
In
wrote:

gurgled happily, sounding much like
they were saying:

As the tolerances for speed cameras are not advertised, then it is
foolish to risk your license by driving past at any mph above the
posted limit.

ACPO's recommended +10%+2 notwithstanding...

ACPO also recommended upping the Motorway limit to 80mph, that was
ignored as well.

You don't understand the difference between recommending a change to
legislation (which requires political agreement) and recommending a
tolerance for enforcement (which doesn't)?

I do, I was just being sarcastic. They don't have much choice with the
tolerance, car speedometers are only legally required to be accurate within
10%.


I think that the 10% margin only applies to over indicating, not under
indicating.

The margin (maybe not so much nowadays) is necessary to allow for tyre
wear (and IIRC tyre type on some vehicles) as well as the capabilities
of a mechanical speedo; the normal consequence of tyre wear is that
the indicated speed will be progressively too high so to avoid
underindication the average speedo will probably already be
over-reading from new.

In message
,
Jeff writes
It doesn't matter what harm he was doing. Potential damage is of some
concern though. Breaking the law is always a concern. It's strange
that some people think they should have the right to choose which laws
they break.
I think it depends on your own common sense. A few weeks ago, it was
mentioned on TV that the government would like to know what laws aught
to be repelled. Now if new laws are being constantly brought in and
old out dated laws aren't repelled, then we'll get to a situation where
you're always in the wrong because of some obscure act of parliament or
other, which you'll fall foul of in the act of trying to conform with
the new law. A bail of hay in a hackney cab, anyone?
--
Clive

In message
Clive wrote:

In message
,
Jeff writes
It doesn't matter what harm he was doing. Potential damage is of some
concern though. Breaking the law is always a concern. It's strange
that some people think they should have the right to choose which laws
they break.
I think it depends on your own common sense. A few weeks ago, it was
mentioned on TV that the government would like to know what laws aught
to be repelled. Now if new laws are being constantly brought in and
old out dated laws aren't repelled, then we'll get to a situation where
you're always in the wrong because of some obscure act of parliament or
other, which you'll fall foul of in the act of trying to conform with
the new law. A bail of hay in a hackney cab, anyone?

That one went decades ago.

--
Graeme Wall

This address not read, substitute trains for rail
Transport Miscellany at www.greywall.demon.co.uk/rail
Photo galleries at http://graeme-wall.fotopic.net/