M49 - link to nowhere

[Big L]

....
So it was completed in 2019, and is currently expected to open in 2024.

I don’t know how they got five years but I’m fairly sure their maths is off!

Post #1 of this thread contains a link to a BBC report saying the junction was finished in late 2019. Late 2019 + 5 years = late 2024.

[Chris5156]

....
So it was completed in 2019, and is currently expected to open in 2024.

I don’t know how they got five years but I’m fairly sure their maths is off!

Post #1 of this thread contains a link to a BBC report saying the junction was finished in late 2019. Late 2019 + 5 years = late 2024.

Oh I see - yes, that makes sense. I read the sentence as meaning “five years after it was built, it’s still two years away from opening”.

[Chris Bertram]

£50m M49 dead-end junction 'still two years from opening' from 2022-05-20

From yesterday's Bristol Live:

The £50million M49 junction-to-nowhere is still two years away from opening –
a whole five years after it was built, according to metro mayor Dan Norris.

Mr Norris says he is “absolutely furious” at the “colossal mistake” between officials
at South Gloucestershire Council and National Highways – formerly Highways England –
that has left the dead-end motorway roundabout near Avonmouth, completed in 2019,
unconnected to the local road network.

So it was completed in 2019, and is currently expected to open in 2024.

I don’t know how they got five years but I’m fairly sure their maths is off!

. It's Retch Reach plc. Nuff said

[gepree68]

Creating the missing link to the ghost junction on the M49 motorway near Bristol is finally happening - as South Gloucestershire Council
has made the first move in what could be a lengthy planning process that will eventually see it built.

The unitary authority has taken the first step to getting planning permission to build the junction, three years after the roundabout on the motorway itself was completed.

https://www.bristolpost.co.uk/news/bris ... nk-7691583

[c2R]

It defies belief that that planning consent wasn't sought for the road and the short missing link at the same time, but surely this shouldn't need a lengthy planning process!? There's nothing of any value about the wasteland, and there can't be anyone seriously objecting to it.

[DB617]

It defies belief that that planning consent wasn't sought for the road and the short missing link at the same time, but surely this shouldn't need a lengthy planning process!? There's nothing of any value about the wasteland, and there can't be anyone seriously objecting to it.

Agreed. I assume the consultation period will only be the statutory minimum, although I could see some of the more misguided environmental lobbyists obstructing it just for the purpose of making a point. But as I said months ago, it is just a joke that a motorway junction could be built without firm plans in place (and I mean contractors appointed) for the roads it will serve. I appreciate that even Almondsbury junction was built with dead arms, but I'm also fairly sure that design and build had already gotten well underway on the following contracts, as most things (and I mean most not all!) were rather more joined up when the network was being built originally - at least on a local scale, if not so much on a national one.

That was of course helped by the vastly reduced admin and consultation burden of much of the planning and building being done in-house by large local authorities. Ultimately it seems unlikely this situation would have occurred if one highway authority was liable for the junction and the linking works.

[Osthagen]

With the utter incompetence of roadbuilding in the UK, with wastes of money like this being built, and halfway decent junction improvements never being considered, I suppose anything goes really.

[M19]

M49-junction.jpg

Creating the missing link to the ghost junction on the M49 motorway near Bristol is finally happening - as South Gloucestershire Council
has made the first move in what could be a lengthy planning process that will eventually see it built.

The unitary authority has taken the first step to getting planning permission to build the junction, three years after the roundabout on the motorway itself was completed.

https://www.bristolpost.co.uk/news/bris ... nk-7691583

Every time I see this I wince at the “design” geometry.

[DB617]

M49-junction.jpg

Creating the missing link to the ghost junction on the M49 motorway near Bristol is finally happening - as South Gloucestershire Council
has made the first move in what could be a lengthy planning process that will eventually see it built.

The unitary authority has taken the first step to getting planning permission to build the junction, three years after the roundabout on the motorway itself was completed.

https://www.bristolpost.co.uk/news/bris ... nk-7691583

Every time I see this I wince at the “design” geometry.

What is it you don't like about it, out of interest?

[c2R]

The design itself is really ugly - function over style....

[DB617]

I guess it's to be expected given it's essentially a new part of Avonmouth Industrial Estate. Nevermind that it's actually a newbuild junction on a major holiday route, I suppose.

[M19]

M49-junction.jpg

https://www.bristolpost.co.uk/news/bris ... nk-7691583

Every time I see this I wince at the “design” geometry.

What is it you don't like about it, out of interest?

Here’s the same type of junction:
https://maps.app.goo.gl/tBvTQCj4UoCRxkfYA?g_st=ic
To turn left you don’t have an awkward entry angle onto the roundabout and therefore, do not have a reverse curve to negotiate to turn left.

With the M49 junction, with the sharp entry it has a reverse curve. Drivers turning left will often ignore the curve to take the straightest most natural path and end up on going wide toward the inside of the roundabout which isn’t good if they do not notice someone alongside them who is turning right. The design encourages entry path overlap. In other words it’s less numpty proof.

[B9127]

I would have thought the Planning Authority would have stipulated a time frame for the developer to complete the missing section

[DB617]

Every time I see this I wince at the “design” geometry.

What is it you don't like about it, out of interest?

Here’s the same type of junction:
https://maps.app.goo.gl/tBvTQCj4UoCRxkfYA?g_st=ic
To turn left you don’t have an awkward entry angle onto the roundabout and therefore, do not have a reverse curve to negotiate to turn left.

With the M49 junction, with the sharp entry it has a reverse curve. Drivers turning left will often ignore the curve to take the straightest most natural path and end up on going wide toward the inside of the roundabout which isn’t good if they do not notice someone alongside them who is turning right. The design encourages entry path overlap. In other words it’s less numpty proof.

Oh, yeah, I see what you mean. That's not good at all. Trying to climb inside the mind of the designers, they probably hoped that drivers could somehow magically detect the reverse curve and slow down appropriately - essentially they have removed the 'passively safe road design' slice of swiss cheese from the safety system. At a junction that is going to be populated with commuters and very large HGVs. Nice.

[tom1977]

Every time I see this I wince at the “design” geometry.

What is it you don't like about it, out of interest?

Here’s the same type of junction:
https://maps.app.goo.gl/tBvTQCj4UoCRxkfYA?g_st=ic
To turn left you don’t have an awkward entry angle onto the roundabout and therefore, do not have a reverse curve to negotiate to turn left.

With the M49 junction, with the sharp entry it has a reverse curve. Drivers turning left will often ignore the curve to take the straightest most natural path and end up on going wide toward the inside of the roundabout which isn’t good if they do not notice someone alongside them who is turning right. The design encourages entry path overlap. In other words it’s less numpty proof.

If you eliminate the reverse curve you won't achieve entry path deflection, which is important on a motorway slip road approach to a roundabout.

[Bryn666]

What is it you don't like about it, out of interest?

Here’s the same type of junction:
https://maps.app.goo.gl/tBvTQCj4UoCRxkfYA?g_st=ic
To turn left you don’t have an awkward entry angle onto the roundabout and therefore, do not have a reverse curve to negotiate to turn left.

With the M49 junction, with the sharp entry it has a reverse curve. Drivers turning left will often ignore the curve to take the straightest most natural path and end up on going wide toward the inside of the roundabout which isn’t good if they do not notice someone alongside them who is turning right. The design encourages entry path overlap. In other words it’s less numpty proof.

If you eliminate the reverse curve you won't achieve entry path deflection, which is important on a motorway slip road approach to a roundabout.

The problem is you can't have multi-lane approaches using the geometry we now expect in DMRB without creating entry path overlap. It is only safe if the entry is a single lane, which is why European roundabouts often have lane drops approaching them so you can't high speed short-cut whereas we slam both lanes at 70 mph straight into the give way lines. Contrast:

https://www.youtube.com/watch?v=qD0s5Po2VJk

This is exactly why the Dutch invented the Turbo Roundabout, it keeps the sharp slow entries which improve safety whilst splitting out the movements so there's no path overlap and high speed short-cutting.

[Chris5156]

With the M49 junction, with the sharp entry it has a reverse curve. Drivers turning left will often ignore the curve to take the straightest most natural path and end up on going wide toward the inside of the roundabout which isn’t good if they do not notice someone alongside them who is turning right. The design encourages entry path overlap. In other words it’s less numpty proof.

If you eliminate the reverse curve you won't achieve entry path deflection, which is important on a motorway slip road approach to a roundabout.

The problem is you can't have multi-lane approaches using the geometry we now expect in DMRB without creating entry path overlap. It is only safe if the entry is a single lane, which is why European roundabouts often have lane drops approaching them so you can't high speed short-cut whereas we slam both lanes at 70 mph straight into the give way lines.

Luckily the new M49 roundabout is fully numpty proof, because the entry points to the roundabout are all single lane, and the circulatory is marked as a single lane too. The circulatory carriageway is only 7m wide so at low speeds you could theoretically get two cars side by side, but it certainly doesn't invite that or look like it's suitable for use in that way and people are unlikely to attempt it.

I agree that deflection and reverse curves on modern roundabouts are a problem, but it's fairly academic in this case!

[Bryn666]

If you eliminate the reverse curve you won't achieve entry path deflection, which is important on a motorway slip road approach to a roundabout.

The problem is you can't have multi-lane approaches using the geometry we now expect in DMRB without creating entry path overlap. It is only safe if the entry is a single lane, which is why European roundabouts often have lane drops approaching them so you can't high speed short-cut whereas we slam both lanes at 70 mph straight into the give way lines.

Luckily the new M49 roundabout is fully numpty proof, because the entry points to the roundabout are all single lane, and the circulatory is marked as a single lane too. The circulatory carriageway is only 7m wide so at low speeds you could theoretically get two cars side by side, but it certainly doesn't invite that or look like it's suitable for use in that way and people are unlikely to attempt it.

I agree that deflection and reverse curves on modern roundabouts are a problem, but it's fairly academic in this case!

I'm sure it was all modelled with no tweaking to suit the budget rather than flow reality...

[Chris5156]

The problem is you can't have multi-lane approaches using the geometry we now expect in DMRB without creating entry path overlap. It is only safe if the entry is a single lane, which is why European roundabouts often have lane drops approaching them so you can't high speed short-cut whereas we slam both lanes at 70 mph straight into the give way lines.

Luckily the new M49 roundabout is fully numpty proof, because the entry points to the roundabout are all single lane, and the circulatory is marked as a single lane too. The circulatory carriageway is only 7m wide so at low speeds you could theoretically get two cars side by side, but it certainly doesn't invite that or look like it's suitable for use in that way and people are unlikely to attempt it.

I agree that deflection and reverse curves on modern roundabouts are a problem, but it's fairly academic in this case!

I'm sure it was all modelled with no tweaking to suit the budget rather than flow reality...

Almost certainly. The constraint on the roundabout carriageway width was the south bridge, which is original to the M49 and was designed to carry a bridleway/accommodation track. It is wide enough for a 7m carriageway so that’s all you get.

[JackieRoads]

M49-junction.jpg

Creating the missing link to the ghost junction on the M49 motorway near Bristol is finally happening - as South Gloucestershire Council
has made the first move in what could be a lengthy planning process that will eventually see it built.

The unitary authority has taken the first step to getting planning permission to build the junction, three years after the roundabout on the motorway itself was completed.

https://www.bristolpost.co.uk/news/bris ... nk-7691583

They might wanna resurface the existing junction so it stays nice and clean, like any ordinary new road.