New A1 junction

[Ian198]

The new junction on the north side of the A1 here to serve the Queen Margaret University College site being developed near Musselburgh now seems complete, awaiting only something to give access to.

Oddly, it has an inbuilt design flaw - the eastbound onslip has no acceleration lane, merely joining at a shallow angle up to a broken line. Given the volume of traffic on this stretch at peak times, this appears very short-sighted.

[A8000Bob]

The new junction on the north side of the A1 here to serve the Queen Margaret University College site being developed near Musselburgh now seems complete, awaiting only something to give access to.

Oddly, it has an inbuilt design flaw - the eastbound onslip has no acceleration lane, merely joining at a shallow angle up to a broken line. Given the volume of traffic on this stretch at peak times, this appears very short-sighted.

It's also rather short sighted that they've built the junction here in the first place. Adding more traffic onto a very busy road...

[Roadtripper_Ian]

Sounds highly dangerous! But as I'm assured that planners are always right it must be safe.

[Mark Hewitt]

Why are they building a junction there? There are two other junctions about 1 km in either direction.

[Ian198]

Why are they building a junction there? There are two other junctions about 1 km in either direction.

Not sure, the only mention I can find here on the QMUC website just states it as fact. Certainly, it will be much shorter, easier and cheaper striking NE from the spot in question than SE or NW from the roads from the Newcraighall or Old Craighall junctions. And access through Stoneybank past Musselburgh station is a non-starter for construction traffic.

There will be a similar junction on the S side of the A1, linked via an underpass.

[David D Miller]

The new junction on the north side of the A1 here to serve the Queen Margaret University College site being developed near Musselburgh now seems complete, awaiting only something to give access to.

Oddly, it has an inbuilt design flaw - the eastbound onslip has no acceleration lane, merely joining at a shallow angle up to a broken line. Given the volume of traffic on this stretch at peak times, this appears very short-sighted.

Looking at the plans on the QMUC website, the sliproad is intended to be extended over an underpass which hasn't been constructed yet. It would have been extremely short-sighted to widen the embankment for a sliproad, only to close it and dig out the underpass a couple of months later! The truncated slip will only be used for construction traffic, so shouldn't be as much of a problem - certainly not when compared with digging up the entire carriageway for the new underpass.

Why are they building a junction there? There are two other junctions about 1 km in either direction.

Not sure, the only mention I can find here on the QMUC website just states it as fact. Certainly, it will be much shorter, easier and cheaper striking NE from the spot in question than SE or NW from the roads from the Newcraighall or Old Craighall junctions.

Additionally, both of those junctions are already somewhat congested. The only road through the area which might still have significant capacity is the mainline of the A1: An extra grade-separated junction here won't make much of a difference, a couple of km out from the terminal roundabout and not quite motorway.

It might also be significant that the whole of the new QMUC campus - including the junction - lies entirely within the East Lothian council area. Taking a new access road out through Newcriaghall would have encroached on Edinburgh's turf, and a route out to the west would go into Midlothian. The junction here means that only one local authority is directly involved.

The completed junction will potentially open up for development another area of East Lothian, land to the southwest of the A1 virtually isolated by the rail loop for the Millerhill yards. I think it's currently designated as green belt, but a suitable rail-connected development would probably get the go-ahead.

Edinburgh already has a precident of major single-use sites getting dedicated accesses from high-speed dual-carriageway: The RBS site at Gogarburn got its new junction on the A8 just a year or so back. The airport junction, with its dumbell roundabout less than a mile further out on the A8, dates from the early 1970s. And a decade earlier, the army base at Craigiehall got its access from the westbound side of the new A90, plus a pedestrian underpass to a bus stop on the eastbound side.

[Ian198]

Looking at the plans on the QMUC website, the sliproad is intended to be extended over an underpass which hasn't been constructed yet. It would have been extremely short-sighted to widen the embankment for a sliproad, only to close it and dig out the underpass a couple of months later! The truncated slip will only be used for construction traffic, so shouldn't be as much of a problem - certainly not when compared with digging up the entire carriageway for the new underpass.

I presume the underpass will be tunnelled throughout, which could be under an extended slip as well as the main carriageways. But if there is some reason for the short slip now, why not design the junction with the underpass suitably further E? Construction lorries leaving the site are likely to be worse things to have at a basic Give Way on a near-motorway than everyday car/van traffic subsequently.

[Ian198]

I queried the slip design with EL Council - have just had this reply:

>The junction and the on slip are designed to the
> DMRB ( Design Manual for Roads and Bridges)and the
> design was carried out by Carl Bro Engineering
> Consultancy on behalf of East Lothian Council. The
> design speed is 50 mph and the onslip includes a 40
> m nose and 75m taper (acceleration lane).
>
> The speed limits on this section of road ( between
> Asda and the A 720 Edinburgh City Bypass) will be
> permanently reduced to 50mph prior to the opening of
> the University ( there is currently a temporary 50
> mph limit in force).
>
> The design and construction have been subject to
> stage 1,2 and 3 safety audits and the safety auditor
> has no concerns regarding the layout of the on slip.

So another D2 is to be given a permanent 50 limit.

[Ritchie333]

This just demonstrates current political thinking. In the past, it would either be designed properly or scrapped. Now any old tat can be put on, the speed limit slashed and lots more cameras put up. Stupid stupid stupid.

[A68Nick]

Oddly enough I don't have a problem with the 50 limit being introduced. It's not far to Jewel roundabout and there's going to be a lot of lane changing with traffic from the Bypass, QMU, Kinnaird Park (or whatever it's called this week!) and Jewel junctinons all merging together. Since the traffic is about to be introduced to an urban environment anyway it makes sense to start stepping things down. Yes, it will be terribly frustrating at 1 am on a Sunday morning, but it's only for a wee stretch. The "Strategic" long distance traffic east of the A720 junction still gets to barrel along as normal. However, many of us will have experienced the queuing traffic for Kinnaird Park that can stretch back along lane 1 of the mainline.

It makes more sense to have the QMU traffic using the A1 then it does trying to navigate through the traffic-hell that is Musselburgh! Even if the road was widened to have sliproad continue as a lane between junctions the volume of weaving traffic would still make it unsafe (M90 J1-2 northbound anyone? - always entertaining when busy!)

Now on the other hand, thinking of 50 limits at busy junctions, the M8/A720 interchange has always puzzled me. North/Westbound the A720 has between reduced to one lane to accommodate merging traffic from the M8. But on the busier, east/southbound side two lanes of M8 slip traffic have to give way to two lanes of A720 traffic. I've never understood why this hasn't been changed to a single lane merge for each.

Cheers,
Nick

[Ian198]

I asked ELC about the underpass construction, too. Yes, it would likely be tunnelled without A1 disruption - but the thinking at present is not for at least 5 years. So until then all traffic will enter/leave the site from the eastbound A1, doing any necessary U-turns at the adjacent full junctions.

[jackal]

Not sure if there's a more recent thread, but in any case preparatory work for upgrade to the QMU junction has now started. This will involve a bridge under the A1 and a new pair of slips on the northbound carriageway, which together with the existing LILO will form a full GSJ. It will serve 1,500 new homes and an 'innovation hub'.



Junction detail: https://i.imgur.com/o2QFbyk.jpeg

It's okay so far as these things go. It extends the short acceleration lane the OP mentions while removing the forced U-turns you get with a LILO. Above all, it's not a flat roundabout. There is a degree of encouragement for public/active travel, with a bus gate across the direct route into Musselburgh, and it's right next to Musselburgh train station.

https://www.eastlothian.gov.uk/news/art ... rsity_site

[owen b]

Not sure if there's a more recent thread, but in any case preparatory work for upgrade to the QMU junction has now started. This will involve a bridge under the A1 and a new pair of slips on the northbound carriageway, which together with the existing LILO will form a full GSJ. It will serve 1,500 new homes and an 'innovation hub'.



Junction detail: https://i.imgur.com/o2QFbyk.jpeg

It's okay so far as these things go. It extends the short acceleration lane the OP mentions while removing the forced U-turns you get with a LILO. Above all, it's not a flat roundabout. There is a degree of encouragement for public/active travel, with a bus gate across the direct route into Musselburgh, and it's right next to Musselburgh train station.

https://www.eastlothian.gov.uk/news/art ... rsity_site

Interesting. I came that way on my way back from Scotland a week ago. I wondered what the lengthy speed limit was for, it extends all the way past the A720 GSJ.

[jnty]

I think a temporary road will be built to carry the A1 while the bridge is being built (like was done with the Bypass for the Borders Railway a few years ago) - any indication of that yet?

[wrinkly]

I think a temporary road will be built to carry the A1 while the bridge is being built (like was done with the Bypass for the Borders Railway a few years ago) - any indication of that yet?

Looking at the plans at jackal's "Junction detail" link, it might be possible to build the bridge in halves (or if that's too difficult then thirds or quarters), with four lanes open during the works, using the space where the slip road tapers will eventually be, without going outside the permanent footprint of the bridge.

[Big Nick]

So this stub of a road will finally see much more use than as lorry drivers rest area?
https://goo.gl/maps/cm5kXLzd14enzBtSA

Good bit of future proofing there even if it has taken 15+ years to get done!