"Perth Transport Futures"

[orudge]

I've never understood the destination choices there either. List everything, be grand...

I can only assume it might be to try to dissuade people who assume that the best way of getting to Coupar Angus, Blairgowrie or Braemar is by driving through the centre of Perth.

[Chris5156]

Edit: I notice that Google Maps has Broxden marked as J12, and indeed there is a solitary reference to it on this sign at the roundabout too. Is that new? I can't think of another example of a spur getting a junction number that belongs beyond the end of the mainline of the motorway.

GSV shows that sticker there as long ago as 2012 (but not in 2009), and I remember it being discussed on here - found it: viewtopic.php?f=1&t=28056&p=573913&hili ... en#p573913 . I must admit, though, I thought the '12' was on the ADS signs on the motorway itself too...

So it was! I had no memory of it.

It could well be on ADS on the M90, but from a quick scan on Streetview I couldn’t see any.

[jnty]

I've never understood the destination choices there either. List everything, be grand...

I can only assume it might be to try to dissuade people who assume that the best way of getting to Coupar Angus, Blairgowrie or Braemar is by driving through the centre of Perth.

Straight through Perth might not be ideal but they're being led through the outskirts of Perth on the A85, rather than on the probably quicker A9 route which bypasses it completely. Bizarre. And you don't have to have looked at a map too carefully to realise you must drive through Blairgowrie to get to Braemar - and Dundee to get to Aberdeen. Edinburgh and Dundee would do the trick, I think, but Coupar Angus does seem to be the nexus of Tayside judging by how heavily signed it is!

[orudge]

Straight through Perth might not be ideal but they're being led through the outskirts of Perth on the A85, rather than on the probably quicker A9 route which bypasses it completely.

I suspect when the Cross-Tay Link Road is open they might consider re-signing this (but wouldn't count on it!).

[jackal]

I would still settle for a flyover onto the M90 - it's not going to solve the whole issue but it links up the direct Edinburgh-Inverness route.

That probably wouldn't be anyone's ideal layout, but it would be a relatively economical and pragmatic way of getting enough traffic off the roundabout that the remainder would flow much better.

I drew this a long time ago as a relatively cost effective way to freeflow Edinburgh-Inverness and Glasgow-Inverness.

This kind of design would never really be built because DMRB says a parclo has lower capacity than a dumbbell

[SouthWest Philip]

My fix for Broxden would be to have the A9 bypass it to the NW, cutting off the corner. I would extend the M90 spur to meet the A9 at a free-flowing trumpet or triangle.

I would replace the roundabout with a simple overbridge with the A93 extended to meet the A9 further west, perhaps at a grade-separated fork.

I would add a new junction on the M90 spur with the B9112 to allow access to Perth.

Unfortunately, it looks like the land to the NW is going to built over making my fix impossible.

[Bryn666]

This kind of design would never really be built because DMRB says a parclo has lower capacity than a dumbbell

There aren't any words for it really, are there? Your design is great but rather hamstrung by development going right up against it.

M5 J5 should be a six ramp parclo, why they've left it as a dumbbell hybrid disaster after the M5 was widened... oh, yeah, you can't have "tight loops" even though Scotland is building parclos everywhere.

[jackal]

This kind of design would never really be built because DMRB says a parclo has lower capacity than a dumbbell

There aren't any words for it really, are there? Your design is great but rather hamstrung by development going right up against it.

The loop for M90 to Perth isn't really needed as an offslip could be provided at the B9112 bridge. So here's an updated one-loop version, which should fit in even with the developments.

[Bryn666]

This kind of design would never really be built because DMRB says a parclo has lower capacity than a dumbbell

There aren't any words for it really, are there? Your design is great but rather hamstrung by development going right up against it.

The loop for M90 to Perth isn't really needed as an offslip could be provided at the B9112 bridge. So here's an updated one-loop version, which should fit in even with the developments.


M90 A9 2022 - Copy.jpg

Gets my vote. I especially like how you've ensured the loop doesn't interact with the northbound entry slip thus retaining free-flow. There's even potential to thread an active travel route through this design into the development to the west, which again the loop is unaffected by if done properly.

[Hdeng16]

Going back to Inveralmond, unless I've missed a cancellation - it's still part of the dualling plan to grade separate it. I can't see any possible way of doing so without removing accesses. Not only that, but even the bypass of a bypass idea specified elsewhere in this thread seems a pipe dream. Even the development to the north and west of Perth it would have to be a massively expensive wide loop through an area I suspect is probably off limits. So we're stuck then?

[jnty]

Going back to Inveralmond, unless I've missed a cancellation - it's still part of the dualling plan to grade separate it. I can't see any possible way of doing so without removing accesses. Not only that, but even the bypass of a bypass idea specified elsewhere in this thread seems a pipe dream. Even the development to the north and west of Perth it would have to be a massively expensive wide loop through an area I suspect is probably off limits. So we're stuck then?

I'm not sure if it is - I've not seen any plans - but I feel like once the CTLR is complete, losing movements from there wouldn't be such a big deal. It may also favourably alter traffic patterns at Broxden too.

[orudge]

The loop for M90 to Perth isn't really needed as an offslip could be provided at the B9112 bridge. So here's an updated one-loop version, which should fit in even with the developments.

Looks like Glasgow/Stirling - Dundee/Aberdeen northbound traffic would have to pass through 2 sets of traffic lights (I assume), which doesn't seem ideal (though we're used to them on the A90 I guess!).

[jackal]

The loop for M90 to Perth isn't really needed as an offslip could be provided at the B9112 bridge. So here's an updated one-loop version, which should fit in even with the developments.

Looks like Glasgow/Stirling - Dundee/Aberdeen northbound traffic would have to pass through 2 sets of traffic lights (I assume), which doesn't seem ideal (though we're used to them on the A90 I guess!).

My first thought was 'you've got to be kidding - 5/6 freeflow is plenty!'. But actually you're right. This is such an important junction (essentially the centre of the Scottish trunk road network) that any missing freeflow between the strategic movements is an issue.

Here, then, is my final offer.

It freeflows all six A9 and M90 movements and still only uses one bridge. The A93 has limited access, with the missing movements via a new junction on the B9112 (see inset).

It's loosely inspired by this junction outside Limerick: https://www.google.co.uk/maps/@52.64119 ... a=!3m1!1e3

[Bryn666]

I like it, but heaven help us if they used the same designer as the person responsible for the A85 junction:

https://goo.gl/maps/bV1btTzzffCY9dx6A

We've only had Guildford rules for 28 years now, you'd think people could work it out...

[orudge]

Here, then, is my final offer.

Works for me!

I guess the M90 northbound would have to be truncated slightly to enable non-motorway access between the B9112 and the A9... to become the un-numbered "(A9)" presumably.

[Hdeng16]

Going back to Inveralmond, unless I've missed a cancellation - it's still part of the dualling plan to grade separate it. I can't see any possible way of doing so without removing accesses. Not only that, but even the bypass of a bypass idea specified elsewhere in this thread seems a pipe dream. Even the development to the north and west of Perth it would have to be a massively expensive wide loop through an area I suspect is probably off limits. So we're stuck then?

I'm not sure if it is - I've not seen any plans - but I feel like once the CTLR is complete, losing movements from there wouldn't be such a big deal. It may also favourably alter traffic patterns at Broxden too.

Ah ok I understand now in terms of the entire project context. Still would seem quite a rarity to get something like that through planning without the retail parks and developments nearby having a moan.

That said I guess this is a similar example of a retail park being 'disconnected': https://www.google.com/maps/@52.107248, ... 384!8i8192

[jackal]

Here, then, is my final offer.

Works for me!

I guess the M90 northbound would have to be truncated slightly to enable non-motorway access between the B9112 and the A9... to become the un-numbered "(A9)" presumably.

Good point. Also the westbound A93 would have to be motorway from the next roundabout along. It's single carriageway and AP in the other direction, though there's space to dual.

I've realised that folding the slips west of the B9112 tightens the weaving space between there and Broxden, so I've edited with the slips now folded to the east of the B9112.

[Burns]

How about a roundabout interchange between the B9112 and the M90 and turning the current roundabout into a directional T and severing access to the current A93?

Seems simple and cost effective but when I pitched it as an idea on the Facebook group I got told off for not considering the effect on the services. Maccies and an overpriced petrol station have a special place in people's hearts, it would seem.

[SouthWest Philip]

How about a roundabout interchange between the B9112 and the M90 and turning the current roundabout into a directional T and severing access to the current A93?

I refer the honourable gentleman to the reply I made some moments [hours] ago!

[orudge]

Could even renumber the B-road to A93 of course in that situation.