Author Topic: Percentage road signs  (Read 45944 times)

Basil

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Re: Percentage road signs
« Reply #25 on: May 27, 2012, 02:26:02 pm »
And that one in Harlech

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Re: Percentage road signs
« Reply #26 on: May 27, 2012, 04:33:56 pm »
I was curious to see how % equated to degrees.



http://en.wikipedia.org/wiki/Grade_(slope)

Re: Percentage road signs
« Reply #27 on: May 27, 2012, 11:27:08 pm »
I was curious to see how % equated to degrees.



That's very interesting; I'd have said that Mow Cop (25%) looked more like 75% when I was climbing it (and looking back down it as well).


Cudzoziemiec

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Re: Percentage road signs
« Reply #28 on: May 27, 2012, 11:37:00 pm »
What's interesting about it IMO is that our percentage signs are in a way misleading; they are based on the ration of up to along, rather than being a percentage of the possible - if they were that, then for instance the 40% sign above would be 20%. For the purposes of clear road signs, or probably almost any part of the Earth's surface, it's better the way we use them.
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Re: Percentage road signs
« Reply #29 on: May 28, 2012, 12:43:13 pm »
Thirty degrees is where avalanche risk gets serious when you're skiing off-piste, it feels pretty horrendous, a lot more so than when you see it on paper. I'd like to know how gradients are actually worked out, Do the engineers just measure the steepest section with a protractor and a level, or do they do it trigonometrically based on rise and 'going' as it's called? I'd break it down into shorter sections myself, the worst cases are the inside of hairpin bends, which have a much steeper gradient than the outside. As anyone riding Hardknott or Wrynose Passes on a Bank Holiday weekend, when there is no choice of route up, will testify.

Pingu

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Re: Percentage road signs
« Reply #30 on: June 05, 2012, 10:59:00 pm »
Top of Suie near Alford:


IMG_0333 by The Pingus, on Flickr

Salvatore

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Re: Percentage road signs
« Reply #31 on: June 13, 2012, 06:41:17 pm »
I was curious to see how % equated to degrees.

http://en.wikipedia.org/wiki/Grade_(slope)

One of the photos of examples of road signs at the bottom of that wikipedia page was taken on the 2007 Elenith. Richard Harding is the rider walker.
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et avec John, excellent lecteur de road-book, on s'en est sortis sans erreur

Re: Percentage road signs
« Reply #32 on: June 13, 2012, 06:53:36 pm »
I've never been skiing, but I'd heard from #1 son that ski slopes can be steep. Having cycled over the Lecht a couple of weeks ago, where you can see clearly the slopes marked out on the mountaintops to the left and right, I can safely say I never will go skiing - I was getting vertigo looking up at them - so god knows how I would feel looking down them  :facepalm:.

Feanor

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Re: Percentage road signs
« Reply #33 on: July 08, 2012, 05:42:32 pm »
Top of Suie near Alford:



Today, the Tap o' Noth is visible.   That's the obvious hill which rises up just behind the metropolis of Rhynie.

Re: Percentage road signs
« Reply #34 on: July 09, 2012, 10:59:57 am »
I forgot I had one of these...


IMAG0159 by Pelotonhound, on Flickr

It's here: MappityClick

Re: Percentage road signs
« Reply #35 on: July 09, 2012, 09:57:39 pm »

Hill on Day 2 of Mille Alba between Edinburgh and Berwick.


NCN1 near Belford. This was of course with full camping gear.


20% Chineway / Chine Hill heading east from Ottery St. Mary. And yes that's full camping gear.
Forgive me Father, for I have sinned. It has been too many days since I have ridden through the night with a brevet card in my pocket...

Pingu

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Re: Percentage road signs
« Reply #36 on: July 10, 2012, 04:38:01 pm »

Hill on Day 2 of Mille Alba between Edinburgh and Berwick.

Redstone Rig (check your Flickr comments  ;) )

Re: Percentage road signs
« Reply #37 on: July 29, 2012, 08:06:21 pm »
I did a bit of a double take when I saw this sign on Friday in Herts:



It is the only pic in this thread of a sign using the proper method of describing a gradient  :P

Incidentally, when I came back the other way today, I noticed the one at the bottom of the hill said 8%. Unless I'm very much mistaken, 1 in 8 is 12.5 percent?! (I didn't stop and take a photo as it was pissing down!)

I also saw another sign elsewhere in Herts saying "1:8" It would seem they like to do it old skool in Hertfordshire....
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mcshroom

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Re: Percentage road signs
« Reply #38 on: July 29, 2012, 08:34:04 pm »
It is the only pic in this thread of a sign using the proper method of describing a gradient  :P

Perhaps that has something to do with the thread title ;)
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Re: Percentage road signs
« Reply #39 on: July 29, 2012, 10:10:25 pm »
It is the only pic in this thread of a sign using the proper method of describing a gradient  :P

Perhaps that has something to do with the thread title ;)

Oh yeah! Maybe I should start a new thread  :P

I wonder how many old skool 1 in x of 1:x signs are left in the UK?
Those wonderful norks are never far from my thoughts, oh yeah!

Cudzoziemiec

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Re: Percentage road signs
« Reply #40 on: July 30, 2012, 10:55:12 am »
I don't think there are many 1:x signs left, but definitely there are still a few. That's the only one I've ever seen though using "in". It looks pretty new, too - or maybe it's just a shiny photo.
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Cudzoziemiec

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Re: Percentage road signs
« Reply #41 on: September 04, 2012, 10:42:45 pm »
No photo, sorry, but saw a 25% sign at the bottom of a hill of the K&A Canal the other day. I have to confess I had planned to ride that way but wimped out when I saw the sign.  :-[ Turned out that hill didn't go quite where I wanted anyway.  :thumbsup: Thing was, on the map it's only marked with one chevron.

Streetview photo

And OS map with one chevron.
sideways bounding monkey lounging under fruit tree

Wowbagger

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Re: Percentage road signs
« Reply #42 on: September 04, 2012, 10:45:01 pm »
It's a long time since I did That Sort of Thing but is not 1:8 the same as 1 in 9?
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Cudzoziemiec

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Re: Percentage road signs
« Reply #43 on: September 04, 2012, 10:52:47 pm »
It's a long time since I did That Sort of Thing but is not 1:8 the same as 1 in 9?
I thought that when we're talking about scales or gradients, 1:8, 1/8, 1 in 8 and 12.5% are all different ways of expressing the same thing?

In a recipe you might say 1 part sugar to 8 parts flour, or whatever, which would mean sugar is 1/9 of the total, but that's ratios of one thing to another, rather than scales.

Isn't it?
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Wowbagger

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Re: Percentage road signs
« Reply #44 on: September 04, 2012, 10:55:17 pm »
As I say, it's a long time, but I have some sort of recollection that 1:8 is the ratio (1 unit vertically to 8 horizontally) whereas 1 in 9 measures the distance you have to go along the road (9 units) before you climb one.  Or something.
Oh, Bach without any doubt. Bach every time for me.

Cudzoziemiec

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Re: Percentage road signs
« Reply #45 on: September 04, 2012, 11:01:15 pm »
Ah - so 1:8 is measuring 8 horizontally whereas 1 in 9 is measuring the 9 along the actual length of the road - the length of the hypotenuse, in effect. Could be, I wasn't aware of that.
sideways bounding monkey lounging under fruit tree

red marley

Re: Percentage road signs
« Reply #46 on: September 06, 2012, 01:35:23 pm »
The difference between the two measures is marginal for typical road gradients (arcTan(1/8) vs arcSin(1/8) giving 7.13o and 7.18o respectively for a "1 in 8"). Road camber, distance over which the gradient is measured and general importance of warning drivers to change their behaviour are going to have far greater effect on the gradient posted.

Cudzoziemiec

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Re: Percentage road signs
« Reply #47 on: September 06, 2012, 02:17:48 pm »
Agreed. But none of that explains why one sign says 1:8 and another 1 in 8 ! (FWIW I reckon it's just a random local decision or sign-printing artefact)
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PH

Re: Percentage road signs
« Reply #48 on: September 12, 2012, 12:54:01 pm »
Three from the Yorkshire Dales, rode down the 20%, up the 16% and the 25% to Aysgarth Falls I rode down and walked back up.






clarion

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Re: Percentage road signs
« Reply #49 on: September 12, 2012, 12:57:52 pm »
These photos make my shoulder twinge when I just think about such hills.
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