In article ,
Roland Perry wrote:
In message , at 16:20:12 on Mon, 9 Jul
2018, John Williamson remarked:
Perhaps you could name a borough that you think is 100% 20mph and I'll
point out the roads in it which aren't.

I can't be bothered checking which ones, but while a few claim to be
completely 20mph, they all have roads which are part of the national
trunk network in them, which are at least 30mph,

And being trunk roads are congested enough that 8mph is a more realistic
figure.

Rubbish. Last time I drove on the A12 from the Green Man to Bow,
it was at the posted speed limit the whole way. And that was
at 5pm-ish, arriving at the Albert Hall at 5:45 (albeit on a Sunday).

A similar journey arriving at the National Theatre at around 6ish
on a Friday evening had a similar average speed.

as they can't set the limits on those roads, due to them being under
DFT control.

I'm not sure which roads are controlled by the boroughs, which by
TfL and which by the DfT; I'm just looking at the boundries of the
boroughs.

--
Mike Bristow

In message , at 17:19:10 on Mon,
9 Jul 2018, Mike Bristow remarked:
In article ,
Roland Perry wrote:
In message , at 16:20:12 on Mon, 9 Jul
2018, John Williamson remarked:
Perhaps you could name a borough that you think is 100% 20mph and I'll
point out the roads in it which aren't.

I can't be bothered checking which ones, but while a few claim to be
completely 20mph, they all have roads which are part of the national
trunk network in them, which are at least 30mph,

And being trunk roads are congested enough that 8mph is a more realistic
figure.

Rubbish. Last time I drove on the A12 from the Green Man to Bow,
it was at the posted speed limit the whole way. And that was
at 5pm-ish, arriving at the Albert Hall at 5:45 (albeit on a Sunday).

A similar journey arriving at the National Theatre at around 6ish
on a Friday evening had a similar average speed.

But we are speaking *average* speeds, not the fastest possible.

as they can't set the limits on those roads, due to them being under
DFT control.

I'm not sure which roads are controlled by the boroughs, which by
TfL and which by the DfT; I'm just looking at the boundries of the
boroughs.

It's my understanding that TfL can veto the 20mph limit on major roads
which are bus routes, bicbw.
--
Roland Perry

In article ,
Roland Perry wrote:
But we are speaking *average* speeds, not the fastest possible.

Yes; but you said that trunk roads in London were so congested that
the average speed couldn't be more than 8mph. But a journey I made,
during the friday evening rush hour, had an average speed well in
excess of 8mph - and the fastest section - by far - was a trunk
road!

And that is a direct counter to your argument.


--
Mike Bristow

In message , at 09:16:04 on Tue,
10 Jul 2018, Mike Bristow remarked:

But we are speaking *average* speeds, not the fastest possible.

Yes; but you said that trunk roads in London were so congested that
the average speed couldn't be more than 8mph. But a journey I made,
during the friday evening rush hour, had an average speed well in
excess of 8mph - and the fastest section - by far - was a trunk
road!

And that is a direct counter to your argument.

You appear not to be able to distinguish between the average speed of
all traffic (over all roads, at all times of day), and the speed you
averaged on one particular trip.
--
Roland Perry

In article ,
Roland Perry wrote:
In message , at 09:16:04 on Tue,
10 Jul 2018, Mike Bristow remarked:

But we are speaking *average* speeds, not the fastest possible.

Yes; but you said that trunk roads in London were so congested that
the average speed couldn't be more than 8mph. But a journey I made,
during the friday evening rush hour, had an average speed well in
excess of 8mph - and the fastest section - by far - was a trunk
road!

And that is a direct counter to your argument.

You appear not to be able to distinguish between the average speed of
all traffic (over all roads, at all times of day), and the speed you
averaged on one particular trip.

You think that trips made outside the peak are going to be *slower*?

--
Mike Bristow

In message , at 11:15:01 on Tue,
10 Jul 2018, Mike Bristow remarked:
In article ,
Roland Perry wrote:
In message , at 09:16:04 on Tue,
10 Jul 2018, Mike Bristow remarked:

But we are speaking *average* speeds, not the fastest possible.

Yes; but you said that trunk roads in London were so congested that
the average speed couldn't be more than 8mph. But a journey I made,
during the friday evening rush hour, had an average speed well in
excess of 8mph - and the fastest section - by far - was a trunk
road!

And that is a direct counter to your argument.

You appear not to be able to distinguish between the average speed of
all traffic (over all roads, at all times of day), and the speed you
averaged on one particular trip.

You think that trips made outside the peak are going to be *slower*?

First, sort out in your head the difference between statistical average
speeds, and the average speed for one specific trip.
--
Roland Perry

On 10/07/2018 11:15, Mike Bristow wrote:

You think that trips made outside the peak are going to be *slower*?

Okay, you made a trip in the rush hour going against the traffic, and
claim that it was made at a good speed. You quote 45 minutes from the
Green Man to the Albert Hall. Fine, that's a fact I can accept.

The same journey in the other direction at the same time (RAH - Green
Man) would probably take almost two hours. That gives an average time of
90 minutes or so to cover at most 10 miles.

On my side of town, I regularly travel from Heathrow to hotels in the
centre of town, and travelling with the main traffic flow in the rush
hour takes about 100 minutes (Using all available bus lanes), where
travelling against it takes 40 minutes or so without using a bus lane.

On occasion, even outside the rush hour, the trip either way can take
well over an hour.

In my experience, bearing in mind I drive in London at all times of the
day and night, the TfL average speeds I quoted earlier in the thread
are, if anything, optimistic.

--
Tciao for Now!

John.

In article ,
Roland Perry wrote:
In message , at 11:15:01 on Tue,
10 Jul 2018, Mike Bristow remarked:
You think that trips made outside the peak are going to be *slower*?

First, sort out in your head the difference between statistical average
speeds, and the average speed for one specific trip.

This subthread started out with you disbelieving the TfL supplied
figures (in , John Williamson quoted
them; in you rubbished them).

After some to-and-froing over the basis of your disbelief I gave
an example journey that more-or-less matched the figures of TfL.

At which point you suggest I misunderstand averages.

You seem to prefer your own theories over the measurements carefully
made by experts which matches the experience of a Londoner who
regularly uses London's roads. I think that's bold; but trying to
be the irresistible argument to your immovable opinion is likely
to bore the audience: don't take my future silence as tacit agreement.



--
Mike Bristow

In article ,
John Williamson wrote:
On 10/07/2018 11:15, Mike Bristow wrote:

You think that trips made outside the peak are going to be *slower*?

Okay, you made a trip in the rush hour going against the traffic, and
claim that it was made at a good speed. You quote 45 minutes from the
Green Man to the Albert Hall. Fine, that's a fact I can accept.

Against the traffic is a fair point from the Green Man to Bow, or
perhaps Poplar; but rapidly becomes less true from there on.

The same journey in the other direction at the same time (RAH - Green
Man) would probably take almost two hours. That gives an average time of
90 minutes or so to cover at most 10 miles.

The last time I drove that sort of route with the flow was probably
from Paddington eastbound; I don't think the traffic was much slower.

The route was different (via the Mile End Road) so it's hard to
make an exact comparison; and it was quite a long time ago so my
memory isn't as clear, so take a pinch of salt or three.

On my side of town, I regularly travel from Heathrow to hotels in the
centre of town, and travelling with the main traffic flow in the rush
hour takes about 100 minutes (Using all available bus lanes), where
travelling against it takes 40 minutes or so without using a bus lane.

Gosh; that sort of difference suprises me. But I don't drive as
often as you do.

On occasion, even outside the rush hour, the trip either way can take
well over an hour.

Oh, yes; I've been lucky recently. If there is the wrong sort of
incident it all goes to pot very quickly (in some locations, anyway).

In my experience, bearing in mind I drive in London at all times of the
day and night, the TfL average speeds I quoted earlier in the thread
are, if anything, optimistic.

Optimistic I wouldn't argue with; I've not seen the detailed
methodology. But total nonsense they aren't - and certainly as you
get further out, average speed do increase quite noticably.

--
Mike Bristow

In message , at 12:13:37 on Tue,
10 Jul 2018, Mike Bristow remarked:
In article ,
Roland Perry wrote:
In message , at 11:15:01 on Tue,
10 Jul 2018, Mike Bristow remarked:
You think that trips made outside the peak are going to be *slower*?

First, sort out in your head the difference between statistical average
speeds, and the average speed for one specific trip.

This subthread started out with you disbelieving the TfL supplied
figures (in , John Williamson quoted
them; in you rubbished them).

"Finding something hard to believe" is a very gentle form of
'rubbishing'.

After some to-and-froing over the basis of your disbelief I gave
an example journey that more-or-less matched the figures of TfL.

Indeed.

At which point you suggest I misunderstand averages.

And you do (misunderstand). Average speed figures are calculated from
thousands of journeys on different roads with different degrees of
congestion (and at different times of day).

The fact you made one journey which 'matched' is simply co-incidence.

I could just as easily have spoken of a trip I did in perhaps 2015 from
Aldwych to Marylebone, about 3.5miles in 45 minutes, and claim that the
8mph figure is therefore wrong.

That was on an unremarkable weekday lunchtime, but anecdata can also be
affected by special events - my most likely reason to be driving in
London these days is traversing Watford and Uxbridge to get to Heathrow
airport because the M25 is closed. I don't expect that to correlate with
any of the published data.

But it can look pretty on a map:

https://scontent-lhr3-1.xx.fbcdn.net...15447893752163
7_7216041464188430701_n.jpg?_nc_cat=0&oh=a39052329 a8fcf074041113eaa72770
c&oe=5BDD14A9

You seem to prefer your own theories over the measurements carefully
made by experts

I was questioning the continued validity of the measurements given the
roll-out of 20mph zones, which are of course a top limit before delays
caused by "weight of traffic", traffic lights, vehicles double parked,
and even road works.

I'd be happier if it was known what radius from the centre TfL's 7.8mph
represented, and thus where 17.4mph kicks in. This 2017 study as London
at 5.13mph (up to 1 mile) and 8.34mph (up to 5 miles):

https://www.aph.com/community/holida...lower-average-
speeds-uks-major-cities-revealed-2017/

Also whether the 8.34mph is for all the traffic within 5 miles, or just
that between 1 and 5 miles. Ditto for the TfL data.
--
Roland Perry