A17 / A15 / A153 Junction Improvements.
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A17 / A15 / A153 Junction Improvements.
Lincolnshire CC has a current scheme to improve two junctions around Sleaford. There has been mention of it previous in the A15 Lincoln Eastern Bypass thread, but I think it's a bit too far fetched to include it in that thread.
The first Junction's works finished today. https://www.lincolnshire.gov.uk/news/ar ... essful-end
This is the Junction between the A17 DC & A153 to the North East of Sleaford and involved adding traffic lights to the Eastbound sliproad and banning right turns (which can be made at the roundabout now instead).
Without realizing it, I happened to cycle through it today. So here is a video of before & after the works were completed.
As you can see, there are now traffic lights & pedestrian/cycle crossings, however these crossing COMPLETELY lack any control, it's not too bad as visibility is okay, however they could of at least put "look right" or "look left" on the edges of the carriageway at the crossings... But it is much easier now to cycle through on a bicycle since its wider and doesn't have such sharp bends in it.
The second junction to get some love is the Holdingham Roundabout (A15 / A17 / B1518). The plan here is to signalise four of the five arms and works are due to start Feb 2021.
Here is the feasibility study for it. I'm sure there is going to be a lot of mixed views on the Holdingham changes! Personally, I think that it will help at peak times, however I'd make them part time signals because most of the time traffic goes through nicely!
The first Junction's works finished today. https://www.lincolnshire.gov.uk/news/ar ... essful-end
This is the Junction between the A17 DC & A153 to the North East of Sleaford and involved adding traffic lights to the Eastbound sliproad and banning right turns (which can be made at the roundabout now instead).
Without realizing it, I happened to cycle through it today. So here is a video of before & after the works were completed.
As you can see, there are now traffic lights & pedestrian/cycle crossings, however these crossing COMPLETELY lack any control, it's not too bad as visibility is okay, however they could of at least put "look right" or "look left" on the edges of the carriageway at the crossings... But it is much easier now to cycle through on a bicycle since its wider and doesn't have such sharp bends in it.
The second junction to get some love is the Holdingham Roundabout (A15 / A17 / B1518). The plan here is to signalise four of the five arms and works are due to start Feb 2021.
Here is the feasibility study for it. I'm sure there is going to be a lot of mixed views on the Holdingham changes! Personally, I think that it will help at peak times, however I'd make them part time signals because most of the time traffic goes through nicely!
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Re: A17 / A15 / A153 Junction Improvements.
The study document is interesting, for a couple of side issues. First, that it uses the expression 'hamburger', in addition to the more official 'through roundabout' or 'through-about'. Is the term now more officially used/accepted? And secondly, that this roundabout, currently and proposed, has the more 'gyratory-shape' or 1960's-urban-shape, ie straight lengths of circulatory between each arm - a shape that I prefer.jervi wrote: ↑Thu Oct 15, 2020 20:54
The second junction to get some love is the Holdingham Roundabout (A15 / A17 / B1518). The plan here is to signalise four of the five arms and works are due to start Feb 2021.
Here is the feasibility study for it. I'm sure there is going to be a lot of mixed views on the Holdingham changes! Personally, I think that it will help at peak times, however I'd make them part time signals because most of the time traffic goes through nicely!
Re: A17 / A15 / A153 Junction Improvements.
There’s a BK top left & a McD bottom right so it may as well be called Hamburger Roundabout. The straights & corners geometry catches out the unwary, you often see someone taking a bit more speed into a corner than they really should and realised they can’t just apex & drift out to the exit as there’s someone else doing the same alongside them.
Re: A17 / A15 / A153 Junction Improvements.
Hamburger is actually mentioned in CD 122, though through-about is preferred:
Perhaps also of note:Through-about
A signalised roundabout, which takes the major through
traffic movements from the circulatory carriageway and
routes them directly across the central island.
NOTE 1: Through-about junctions are also referred to as
"hamburgers" and "fly-through roundabouts".
In any case, there's no requirement to use DMRB's sometimes eccentric junction names (e.g., "4 way restricted height interchange" for a partially unrolled cloverleaf).Double-through-about
A development of the through-about principle but with two
conflicting traffic movements routed across the central
island of the roundabout.
NOTE 1: A double-through-about is also known as a
"hot-cross-bun".
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Re: A17 / A15 / A153 Junction Improvements.
Do any hot-cross-buns exist? To me, a hamburger is no longer, functionally, a roundabout for the majority of users. With two crossing movements removed from the circulation I fail to see how any pretence of rotary arbitration can be maintained, no matter how many arms enter in total.
I noticed recently, while looking at hamburgers on google earth, that Manchester is well-endowed. Is it the hamburger capital?
I noticed recently, while looking at hamburgers on google earth, that Manchester is well-endowed. Is it the hamburger capital?
Re: A17 / A15 / A153 Junction Improvements.
Bit late to the party, but not really sure why they didn't just put in a small roundabout here so the junction effectively becomes a dumbbell. I'm guessing space is tight on the east side with the rugby club there, but to untrained eye it looks possible with encroachment on the west side, which looks like unused scrubland. The non-right turn is also a little curious - I get it from the sense that it's one less signal sequence but feels a bit strange. Ok it's not that much of an imposition to do a 360 at the roundabout and come back but still, having to potentially sit and wait at red lights twice just to go from A153 to A17 east could grate...
As for the Holdingham roundabout proposals, I'll admit right away I haven't bothered to do any more than skim that document. But it chimes a bit with the A45/A6 Chowns Mill scheme - sticking plaster solutions to an over-burdened roundabout that won't really stand the test of time. I guess it's not out of place on the A17, which is fairly inadequate for the majority of its length.
As for the Holdingham roundabout proposals, I'll admit right away I haven't bothered to do any more than skim that document. But it chimes a bit with the A45/A6 Chowns Mill scheme - sticking plaster solutions to an over-burdened roundabout that won't really stand the test of time. I guess it's not out of place on the A17, which is fairly inadequate for the majority of its length.
Re: A17 / A15 / A153 Junction Improvements.
The A408/M4 Spur junction north of Heathrow was one, and it got removed because it was... rubbish.Peter Freeman wrote: ↑Fri Oct 16, 2020 09:01 Do any hot-cross-buns exist? To me, a hamburger is no longer, functionally, a roundabout for the majority of users. With two crossing movements removed from the circulation I fail to see how any pretence of rotary arbitration can be maintained, no matter how many arms enter in total.
I noticed recently, while looking at hamburgers on google earth, that Manchester is well-endowed. Is it the hamburger capital?
Bryn
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Terminally cynical, unimpressed, and nearly Middle Age already.
She said life was like a motorway; dull, grey, and long.
Blog - https://showmeasign.online/
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Re: A17 / A15 / A153 Junction Improvements.
Does the Black Dam at Basingstoke count? It's got three of the four arms of the cross...Peter Freeman wrote: ↑Fri Oct 16, 2020 09:01 Do any hot-cross-buns exist? To me, a hamburger is no longer, functionally, a roundabout for the majority of users. With two crossing movements removed from the circulation I fail to see how any pretence of rotary arbitration can be maintained, no matter how many arms enter in total.
Re: A17 / A15 / A153 Junction Improvements.
That specific one was a skidpan of tarmac strewn with traffic lights, and four little vestigial islands separating the crossroads from the circulatory carriageway. It's for the best that it was abandoned - it works much better as a hamburger.Bryn666 wrote: ↑Fri Oct 16, 2020 11:10The A408/M4 Spur junction north of Heathrow was one, and it got removed because it was... rubbish.Peter Freeman wrote: ↑Fri Oct 16, 2020 09:01Do any hot-cross-buns exist? To me, a hamburger is no longer, functionally, a roundabout for the majority of users. With two crossing movements removed from the circulation I fail to see how any pretence of rotary arbitration can be maintained, no matter how many arms enter in total.
That said, I'm increasingly of the view that hamburgers, hot cross buns, bananabouts and all the other weird signalisation tricks are part of the strange and indefensible UK fetish for clinging on to a roundabout in all circumstances, even when you end up producing a junction that doesn't function as a roundabout at all. The money spent on the A408 junction, the Black Dam Roundabout at Basingstoke and countless others would surely have been better used to reconstruct them as actual signalised junctions, with appropriate channelisation and signal timings.
My least favourite wishing-it-was-a-roundabout disaster zone is M4 J12 at Reading, two interconnected junctions whose designers were desperate to retain as roundabouts even when the whole thing was effectively built from scratch, complete with new bridges over the M4, and everything shuffles around under control of traffic signals and using cut-throughs and bypass lanes. They could have built anything, but they built that. Yuck.
Chris
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Re: A17 / A15 / A153 Junction Improvements.
I'm not really sure the A17/A15 roundabout needs signals. it's a bit congested with all the services and stuff around it though, guess there's not a great deal you could do about that.
Fortunately it's relatively large and there's no natural obstructions to the terrain.
A much better fix would be to pop the A17 over the top. You'd need a bit more dual on the west side, but on the A17 that is not a bad thing.
The A15 would then only need to intersect the slip roads of the A17, whatever local services are there, and the B road which was the old A15. The latter could just be a simple T junction involving the south arm of the roundabout. You could then close off the rest of the roundabout and pop the A15 through the middle too at ground level. Then you'd just fit the slips into the A17 somewhere.
I don't think there would be a majority of traffic changing roads here, as opposed to staying on either the A17 or A15. The A16 and A1 / A46 are much better options than the A15 for any A17 traffic heading to either Lincoln or Peterborough.
Fortunately it's relatively large and there's no natural obstructions to the terrain.
A much better fix would be to pop the A17 over the top. You'd need a bit more dual on the west side, but on the A17 that is not a bad thing.
The A15 would then only need to intersect the slip roads of the A17, whatever local services are there, and the B road which was the old A15. The latter could just be a simple T junction involving the south arm of the roundabout. You could then close off the rest of the roundabout and pop the A15 through the middle too at ground level. Then you'd just fit the slips into the A17 somewhere.
I don't think there would be a majority of traffic changing roads here, as opposed to staying on either the A17 or A15. The A16 and A1 / A46 are much better options than the A15 for any A17 traffic heading to either Lincoln or Peterborough.
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Re: A17 / A15 / A153 Junction Improvements.
A large proportion of traffic here does actually change route, which is why a standard GSJ was basically out of the question. One of the shortlisted options looked at was a throughabout of A17(WB)-A15(SB) (and reverse).ForestChav wrote: ↑Sat Oct 17, 2020 22:14 I don't think there would be a majority of traffic changing roads here, as opposed to staying on either the A17 or A15. The A16 and A1 / A46 are much better options than the A15 for any A17 traffic heading to either Lincoln or Peterborough.
Re: A17 / A15 / A153 Junction Improvements.
If that told against a GSJ it would tell against a throughabout, which is essentially just a cheaper version of a roundabout GSJ with lower turning capacity as the turning traffic has at-grade conflicts with the 'straight ahead' movements. Much more likely a GSJ was discounted on cost or land take grounds.jervi wrote: ↑Sun Oct 18, 2020 01:01A large proportion of traffic here does actually change route, which is why a standard GSJ was basically out of the question. One of the shortlisted options looked at was a throughabout of A17(WB)-A15(SB) (and reverse). holdingham.PNGForestChav wrote: ↑Sat Oct 17, 2020 22:14 I don't think there would be a majority of traffic changing roads here, as opposed to staying on either the A17 or A15. The A16 and A1 / A46 are much better options than the A15 for any A17 traffic heading to either Lincoln or Peterborough.
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Re: A17 / A15 / A153 Junction Improvements.
There was a big chunk of discussion somewhere about both junctions, there were 3 options for the A17/A153 junction - two being roundabouts and one being signals. Roundabout would have been better in my opinion, but the signals apparently make it better for pedestrians.
As for the Holdingham plans, I reckon an A17-A17 hamburger would have fixed it forever. It only really gets overloaded when it's trying to handle holiday/coast traffic, which is usually wanting to go straight across the A17. Chances of seeing a GSJ there ever are probably non existent, as with the chances of seeing the A17 to the west dualled. So a hamburger with some approach widening for a decent length (eg A17 approach from the west having 2+ approach lanes back to the DVSA checkpoint) would more than likely do a job on it...
As for the Holdingham plans, I reckon an A17-A17 hamburger would have fixed it forever. It only really gets overloaded when it's trying to handle holiday/coast traffic, which is usually wanting to go straight across the A17. Chances of seeing a GSJ there ever are probably non existent, as with the chances of seeing the A17 to the west dualled. So a hamburger with some approach widening for a decent length (eg A17 approach from the west having 2+ approach lanes back to the DVSA checkpoint) would more than likely do a job on it...
Re: A17 / A15 / A153 Junction Improvements.
That suprises me as I can't see why there is much demand for A17 traffic to head south at this point. All I can think of is A153 through traffic doing this, as it mutiplexes with the A17 and A15, but I'd have thought levels of A17 through traffic must be much higher, as seen here because the approach of the A17 dual carriageway has the left hand lane marked out for the A15 southbound with A17 traffic having to use the right hand lane.
Re: A17 / A15 / A153 Junction Improvements.
For me as a kid living a little further down the A15 we only ever went A15 - A15 (in both pre & post A15 bypass times). I've moved further east since then so now I'm more likely to go through A17 - A17 & back again although I have done A15N to A17E in its guise as A153, except most recently while that's been altered.skiddaw05 wrote: ↑Sun Oct 18, 2020 22:59That suprises me as I can't see why there is much demand for A17 traffic to head south at this point. All I can think of is A153 through traffic doing this, as it mutiplexes with the A17 and A15, but I'd have thought levels of A17 through traffic must be much higher, as seen here because the approach of the A17 dual carriageway has the left hand lane marked out for the A15 southbound with A17 traffic having to use the right hand lane.
Re: A17 / A15 / A153 Junction Improvements.
I concur with the surprise that there should be a large amount of A17 WB traffic would want to head south on the A15 here, seems illogical (not that I am doubting Jervi). Surely any goods vehicles coming to/from Boston heading to/from the A1 are either going all the way on the A17, or taking the A52 all the way. And on the flipside, I'm not really sure why A15 NB traffic would be swinging east onto the A17, when again (unless they are originating from the local villages), the A52 seems the logical option if you're wanting to go east. Very curious.
Re: A17 / A15 / A153 Junction Improvements.
There are diagrams of the traffic movements in the document I linked on the OP, page 45.
The rough percentages of traffic going ahead are:
A17(EB) - 70%
A17(WB) - 30% (majority of traffic turns off)
A15(SB) - 27% ("ahead" is second lowest arm, most popular is B1429 at 45%)
A15(NB) - 55%
From B1518 there is almost equal distribution across all arms (120 vehicles / hour(AM Peak)), except A15(N) which has 220.
Some movements have very little traffic (i.e. traffic can use the B1429 between the A15(N) and A17 (W)), while there are a lot of movements to/from the B1518 which go in all directions too.
The rough percentages of traffic going ahead are:
A17(EB) - 70%
A17(WB) - 30% (majority of traffic turns off)
A15(SB) - 27% ("ahead" is second lowest arm, most popular is B1429 at 45%)
A15(NB) - 55%
From B1518 there is almost equal distribution across all arms (120 vehicles / hour(AM Peak)), except A15(N) which has 220.
Some movements have very little traffic (i.e. traffic can use the B1429 between the A15(N) and A17 (W)), while there are a lot of movements to/from the B1518 which go in all directions too.
Last edited by jervi on Mon Oct 19, 2020 18:00, edited 1 time in total.
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Re: A17 / A15 / A153 Junction Improvements.
Yeah I'm surprised too, surely anything which it would use the A15 for could be reached via the A52 and cut a corner off.danfw194 wrote: ↑Mon Oct 19, 2020 12:25 I concur with the surprise that there should be a large amount of A17 WB traffic would want to head south on the A15 here, seems illogical (not that I am doubting Jervi). Surely any goods vehicles coming to/from Boston heading to/from the A1 are either going all the way on the A17, or taking the A52 all the way. And on the flipside, I'm not really sure why A15 NB traffic would be swinging east onto the A17, when again (unless they are originating from the local villages), the A52 seems the logical option if you're wanting to go east. Very curious.
C, E flat and G go into a bar. The barman says "sorry, we don't serve minors". So E flat walks off, leaving C and G to share an open fifth between them.
Never argue with an idiot. They will bring you down to their level and beat you with experience.
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Re: A17 / A15 / A153 Junction Improvements.
Seems like half way into the project and LCC decided to release a render of Holdingham roundabout. https://www.youtube.com/watch?v=v6Bty_DXPlA
Of course there are some signage issues which are glaring out.
Of course there are some signage issues which are glaring out.
Re: A17 / A15 / A153 Junction Improvements.
Just some of the final surface on a few of the arms needs to be done along with signage & commissioning of the signals .
Looks like it will complete on time.