A380 Speed limit

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avtur
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Re: A380 Speed limit

Post by avtur »

I am an aviation nut case ...I saw A380 and went in a totally different direction ... an A380 cruises at 900km/hr :laugh: :laugh: :laugh:
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Keiji
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Re: A380 Speed limit

Post by Keiji »

As a local:

1. The Penn Inn flyover is only D1 because the Sainsbury's building is too close to permit a D2. (The flyover being D1 probably helps traffic at the junction anyway - though I'd argue that ideally it ought to be a D2 flyover at Penn Inn with D3 between Ware Barton and Aller, to give lane gains/drops at the junctions where they are most needed.)

2. The narrow section between Penn Inn and Aller is 50mph because it is narrow (look at how narrow the central reservation is). To me at least, 50mph feels natural on this stretch, while 70-80 feels natural on the section between Telegraph Hill and Ware Barton, so I'd say this is entirely justified.

3. The section between Aller and Edginswell is 50mph to reduce noise (contrary to some other posts in this thread). This was originally going to be 70mph but it was reduced for this reason - I remember reading this in one of the official publications at the time. Even if Sainsbury's wasn't there and more land could have been claimed for the narrow bit allowing a 70mph geometry, I reckon the whole thing would still have been 50mph for noise reasons. I remember that the new end bit of M74 in Glasgow has a speed limit of 50 or 60 along with a sign stating "Speed limit in place to reduce noise" or something to that effect and I do wish that this one on the A380 had a similar explanatory sign, as I do believe most drivers would be happier to obey a restriction if they understood the reason behind it - though the cameras do do their job of ensuring compliance perfectly well enough.

4. For a time, there were no average speed cameras on the 50mph section. At this time I frequently found the left hand lane doing about 45mph indicated (~42mph GPS) and the right hand lane doing 60-65 indicated. This made it very difficult for me personally, as I wanted to do 51 indicated (49 GPS) to suit the speed limit and my engine, but I certainly couldn't do this in the left hand lane, sitting in the right hand lane would cause a huge queue behind me, and constantly weaving in and out to do the proper thing was both tiresome and a wear on my car (constantly accelerating and braking). I can't speak for anyone else but I'm very happy with the average speed cameras being there, as it means that both lanes now move smoothly and very close to 50 at all times, and no one gets grumpy if you sit in the right hand lane at 50 (okay, there is still the occasional tailgater, but it's now very much the exception rather than the rule) - which was exactly what I'd expected from experience with average 50's at motorway roadworks. It's imo a vast improvement having the cameras there.

5. The speed limit southbound used to begin rather closer to Penn Inn. This was extended back quite some way because there were frequent collisions here (typically rear-end shunts or sideswipes) due to people needing to suddenly get in lane and suddenly approaching a queue at rush hour due to the D1 flyover - or perhaps due to reckless drivers skipping the queue at ridiculous speeds then trying to get a place or having someone pull out on them. I haven't heard of a single collision here since the speed limit extension, and it feels much safer to drive too. It also seems to have lightened congestion a little, which you'd expect (for the same reason that we have VSL on congested motorways). The northbound 50 was quite rightly not extended when the southbound was, though I do think the NSL sign northbound ought to be placed a little sooner. I don't remember which came first between the average speed cameras mentioned above and the extension of the 50 limit.

Hopefully this provides some useful insight into why X bit of the A380 is 50 when Y other bit isn't! :)
ikcdab wrote:The irony is that this 50mph section is termed the South Devon Expressway.
It does seem ironic when considered only in terms of what is there now. However, it takes about 5 minutes to do Penn Inn to Edginswell on the Expressway - it previously took typically 20 minutes, or 30-40 at bad times, to do this on the old 40mph limit road through Kingskerswell. Many drivers frequently used the Milber lanes, or even the Edginswell/Kingskerswell Village/Decoy lanes, to avoid it - myself certainly one of them - virtually all this traffic is now combined onto the new D2. I certainly see the new stretch as an Expressway, and probably every other local driver from 10-15+ years ago does too. Remember also that the A38 around here is called "The Devon Expressway", and yet runs through notoriously bendy bits near Chudleigh, with an advisory 50 limit northbound (I typically do this at about 40 indicated - most others do pass me here but hardly anyone goes anywhere near 70).
mikehindsonevans
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Re: A380 Speed limit

Post by mikehindsonevans »

avtur wrote: Mon Jun 20, 2022 20:06 I am an aviation nut case ...I saw A380 and went in a totally different direction ... an A380 cruises at 900km/hr :laugh: :laugh: :laugh:
You are not alone. I was thinking Mach 0.86!!
Mike Hindson-Evans.
Never argue with a conspiracy theorist.
They will drag you down to their level and beat you with experience.
Bendo
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Re: A380 Speed limit

Post by Bendo »

Keiji wrote: Tue Jun 21, 2022 15:12
5. The speed limit southbound used to begin rather closer to Penn Inn. This was extended back quite some way
Do you know when it was extended? I'm sure it's only recent as I only noticed it this half term gone (think I did well to spot it at about midnight having driven 3.5 hours). Fairly sure it wasn't extended the previous school holidays back at the start of April. If it was the cameras weren't working as I'm fairly sure I'd have done 77 GPS past it
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Keiji
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Re: A380 Speed limit

Post by Keiji »

A bit of googling took me to this article: https://www.middevonadvertiser.co.uk/ne ... ach-265502

That article is talking about the extension I mentioned and is dated 16th Nov 2018, so presumably it would have happened within a few months from that date. That about agrees with my vague memory (which could only say it was pre-Covid). It also mentions the then-future installation of the cameras, but the timings are such that it doesn't confirm whether the speed limit extension or the cameras were installed first.

The cameras at the north end of the speed check stretch are here, nearly on the Penn Inn flyover itself, so they don't cover the extension.
Bendo
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Re: A380 Speed limit

Post by Bendo »

Keiji wrote: Wed Jun 22, 2022 10:18 A bit of googling took me to this article: https://www.middevonadvertiser.co.uk/ne ... ach-265502

That article is talking about the extension I mentioned and is dated 16th Nov 2018, so presumably it would have happened within a few months from that date. That about agrees with my vague memory (which could only say it was pre-Covid). It also mentions the then-future installation of the cameras, but the timings are such that it doesn't confirm whether the speed limit extension or the cameras were installed first.

The cameras at the north end of the speed check stretch are here, nearly on the Penn Inn flyover itself, so they don't cover the extension.
Doh sorry need to not post late at night. What I actually meant was at some point between April and June, a new camera has been added that covers the extension.

Normally as it's approaching midnight when I pass that way, I'd reduce my speed at the flyover but my last visit I spotted the new camera. I'm fairly sure it wasn't there in April as I didn't see it or collect points for doing 77 between there and there flyover.
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Keiji
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Re: A380 Speed limit

Post by Keiji »

I've not noticed a new camera there and I like to think I'm pretty observant about these things. I'll try and remember to keep my eyes especially peeled next time.
Bendo
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Re: A380 Speed limit

Post by Bendo »

Looks like it was done in May, which fits with me not seeing it in April

https://www.bbc.co.uk/news/uk-england-devon-61591933
https://www.devonlive.com/news/devon-ne ... ed-7126246
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wrinkly
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Re: A380 Speed limit

Post by wrinkly »

Herned wrote: Sun Jun 19, 2022 00:12 It has a lower design speed to save money - from memory that means it needed less land and earthworks as curves are a bit tighter and the distance of forward visibility could be reduced. It doesn't have 1m hard strips either
The A380 is a non-trunk road and the most recent section was designed at a time when local authorities were under intense pressure from central government to cheese-pare schemes. I think it was in Osborne's early days as chancellor, when he was slashing inherited projects such as the northern half of A1 Dishforth-Barton, before he did a partial U-turn on infrastructure.
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ajuk
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Re: A380 Speed limit

Post by ajuk »

If they're having to put an average speed camera up then that's almost an admittance that the road was engineered for a faster speed if you have to have constant enforcement of it it's not "encouraging self-compliance"

They also have some widely disregarded and almost never enforced 40 limits on the approach to roundabouts, if anything they may cause some people to brake too early endangering traffic behind.
The whole having speed limits for roundabouts thing winds me up, as if anyone who would approach a roundabout at some ridiculous speed will pay attention to lower speed limit and especially one that starts in an arbitrary location some distance away from the roundabout.
They're put a 40 limit on one near me and getting to 40 round there would be scary.

I can only think it's possibly some kind of anti-litigation measure however there does exist a roundabout ahead slow down and 40mph max speed advisory sign, so I don't know why they don't use that.
DB617
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Re: A380 Speed limit

Post by DB617 »

South Glos is awful for this - the entire Ring Road has 30 signs on the roundabout approaches, which also linger far too long onto the next stretch of D2. Remember that drivers on black boxes will be expected to observe these limits every single time or face action from employers or insurers. You can imagine the sort of punishment behaviour I and my colleagues faced doing 30 off a roundabout on a D2.
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