Where is it?
Halfway around the A720 Edinburgh City Bypass, where two of the city's radials cross the bypass and each other.
It was nominated by Chris Williams.
What's wrong with it?
Imagine, if you will, the city of Edinburgh. Around its southern fringe lies the A720, otherwise known as the City Bypass, a grade-separated dual carriageway (complete with hard shoulders and motorway-like restrictions) that speeds traffic around the urban area. It's like some kind of dream.
However, largely thanks to this junction, if the A720 is any kind of dream, it's the sort that makes you wake up screaming at three in the morning. It's pretty obvious from the diagram what's wrong with it — it's a roundabout. Traffic chaos day and night is caused by the fact that this junction, in the middle of what is effectively a motorway, is one flyover short of adequacy.
Naturally, traffic engineers have done their best to entertain those stuck in the congestion this roundabout causes by surrounding it with cheery red, amber and green disco lights.
Why is it wrong?
There are two schools of thought on this one, and each is equally plausible. The first is the more optimistic; when the Bypass was designed and built it was thought that the volume of traffic entering or exiting the road here would be a significant proportion (ie, the flows of traffic between the two arms of the A720 would not be heavy enough to warrant grade separation). With the benefit of hindsight (and all the thinking time that a typical Sherriffhall traffic jam permits), it's clear as day that this idea was wrong.
The other, more frightening, answer is that the junction is built on the site of old mine workings, and that this made grade separation impossible. The ground is not stable enough to support a flyover. This is backed up by the fact that the design of the junction does not even leave room for future grade separation. If this reason is true, then the future looks grim for regular users of this junction.
What would be better?
A flyover and a free-flowing A720. Or an underpass. Anything. Please. Quickly.
Right to reply
If Sheriffhall is built over former mine workings, then this suggests that an underpass, as well as being the only structurally possible solution, is likely to be half-built already if you see what I mean.
This is the junction which makes the Sunday trip to Ikea a total nightmare, as if it wasn't bad enough! This junction is just one of a few reasons why the A720 falls well short of the standard it should be. The Hermiston Gait roundabout at the end of the M8, Old craighall roundabout where the A720 meets the A1 and the fact that although there are restrictions, you can still drive a tractor or a JCB on the bypass! In short, the road is best avoided completely at peak times.
The tailbacks can be so long on the A720, morning noon and night, that eastbound drivers often decide to take off on a little rat-run through south-east Edinburgh, taking the previous junction for the A772 into town, through Gilmerton and Danderhall on the B701, then on to the A7 to approach Sherriffhall from the north where the queues are supposed to be much shorter. But given the awful state of this junction, even the rat-run is getting clogged - it's beyond reproach!
The real reason why this junction is a roundabout and not properly grade-separated is definitely the second reason, that there are abandoned mine workings in the vicinity which make grade-separation too risky. Not so very long ago there was even trouble when some nearby houses started subsiding and the occupiers had to be rehoused at some expense. Since the A7 is one of the main routes into and out of Edinburgh, it's highly unlikely that the first explanation was ever close to reality.
All this aside, it sucks - I've been stuck at this roundabout myself, in hot weather - but I'd prefer that to slowly sinking into the ground.
Sherrifhall Roundabout was built as the "temporary end" of the A720 before it was finally connected to the A1. When the city bypass was eventually joined up, Edinburgh City Council short sightedly refused to entertain a grade seperated junction on the basis of cost, despite this being the only truly workable and sustainable solution.
Indeed, there are abandoned mine workings in the area but as has been proved in many areas of the UK these can be VERY successfully grouted and as a result are perfectly stable and safe.
This is just another of the spectacular failure of Edinburgh's Transport planners over the last 50 years!
As a transportation engineer myself I am dismayed at how many "quick fixes" are made to ensure re-election rather than solve transport issues - this applies at both local and national level.
Baillieston A8/M8/M73 Interchange sits atop at least three old colliery workings.
While there is not much to say in favour of Sheriffhall, the old A7, now A772, does have a flyover of the A720 a bit to the west, helping to reduce the conflict.
A new junction is about to be added half a mile east of this for the new A68 Dalkeith eastern By-pass. This may either imporve or, more likely, make matters worse here. The A720 queue west bound will have added traffic from the A68 and the local traffic from Dalkeith will still use the existing access to the A720 at Sheriffhall. The new junction does have a flyover - and is just as close to the mine workings at Danderhall. Does this mean the flyover could have been built at Sheriffhall?
Our normal approach to the Edinburgh City by-pass is from the south east via A68, or occasionally by A7. We have devised various ways of avoiding this junction, and its lengthy queues, by taking one of the alternative routes out of Dalkeith (which usually has its own traffic jams), cutting across to the A7 roundabout by Dobbies Garden Centre, then joining A720 westbound at the next junction to the west (A772 Gilmerton Road). Surprisingly there are no helpful signs to indicate this route, as even at the A7/A772 junction signs for A720 westbound still take you towards the roundabout and traffic lights. As for the southern approach to the Forth Road Bridge, that needs an Ordnance Survey map and the ability to navigate around back lanes to avoid 90% of the queue!
Oh dear, oh dear, this is just the WORST roundabout I've been...erm, around. I thought Sandyknowes near Belfast was awful, but this one just doesn't bear thinking about. It turns a great bypass into a nightmarish crawl...
In the evenings, traffic is frequently backed up from Sheriffhall for six miles to the M8 roundabout to the west of Edinburgh (in itself a very bad junction). From the south-east, once I have cleared the Black Cat, it is usually my first hold-up for 350 miles. There seems to be no intention to do anything about it.
I drive a car transporter (over 20m) around this roundabout on the A720, between the A1 and the rest of Scotland. The eastbound approach really tightens to the left. This leaves me no option but to occupy both lanes (splitting the lanes) so as to get my trailer round without mounting kerbs. This really annoys other motorists but sorry guys, I've no choice. Then if I'm caught by a red at the two sets I pass, while on the roundabout, I just block the exit and entry of the road to my left. This isn't so much a problem up north as people usually have more patience but I've noticed it's getting worse. I personally have no complaints about lights on roundabouts. But please planners, not on small ones that I easily block.
Now being 'widened' so that there are four complete lanes around the roundabout. Causing complete chaos during construction (Jul 08) and not clear if this will make any improvement. Nearby the A68 Dalkeith Bypass nears completion and will bring new problems. Best idea would be to combine A7 and A68 as one entry point.
As the A68 Dalkeith bypass now joins the A720 to the northeast of Sheriffhall (the old A68 through Dalkeith being the extended A6106), so A68 traffic either uses the roundabout via the A720, or misses it altogether.
Grout the mineworkings, build the flyover, then merge the A6106 into the A7 on both sides of the roundabout so there are only 4 arms going into the roundabout. Or shift the A720 to the north or south of its current alignment to find stable ground and build a flyover junction.
The whole roundabout problem is exacerbated by Edinburgh Council's siting of a Park and Ride on the Edinburgh side A7. This is meant to prevent traffic going into Edinburgh, but means that people who live on the south or east of the roundabout have to negotiate the roundabout to get to the park and ride. If only they had build the P&R on the east side of the roundabout, the traffic on the roundabout would have been significantly reduced.
I also agree about the A6106 - that road should be diverted to join the A7 further east - say at the park and ride.
This junction always reminded me of another bad junction - Broadway, on which the M1(NI) terminated. Recently they undertook a project to create an underpass, despite challenges (redirecting rivers and flooding).
Edinburgh is twice the city Belfast is (and much nicer IMHO), I can't see why they can't "Broadway" Sherrifhall.
I think part of the issue is that the route of the Waverley rail line, closed in the 1960s but due to be reopened, runs under the bypass at Sheriffhall.
40 years in the railway industry (until Oct last year), meant I always tried to keep up to speed on rail developments. Looking at the detailed OS map available off the link, the re-opened Waverley route will pass about 300 metres east of the roundabout. The bypass was built years after the railway closed, so there is no bridge, and never was one. So the works to put a bridge in is a golden oppportunity to sort this junction out and put in a flyover.
Lets hope the Scottish Executive takes this opportunity !
There are now three options being considered to make the junction free-flowing. One includes closing the junction and making the nearby Gilmerton exit work for all directions. Still some time until any decisions to be made though! Expect nothing before 2018!