Question about Sherriffhall roundabout at FMQs. Congestion and danger to drivers and cyclists. But what is 'grade separation'?
CityCyclingEdinburgh Forum » Infrastructure
'grade separation'?
(22 posts)-
Posted 13 years ago #
-
Bridge/tunnel/flyover.
Posted 13 years ago # -
Yes, a "grade separated junction" is one where you have sliproads and then a bridge over/under the main road. (There are occassional uses to being the child of a Town Planner).
Posted 13 years ago # -
Grade separation is the process of aligning a junction of two or more roads at different heights, so as not to disrupt the flow of traffic on either route at the point where they intersect. This is usually achieved by creating an overpass or underpass on one, or more, of the routes at the intersection.
Posted 13 years ago # -
Most of the junctions on the city bypass are grade separated: Hermiston, Calder Road, Baberton, Dreghorn, Lothianburn, Straiton, Lasswade, Gilmerton, Dalkeith for A68, Old Craighall for A1; and Newcraighall/A1 is as well.
Sheriffhall isn't, and cycling across it when following Old Dalkeith Road tends to put hairs on your chest.
Edit: Drat! Missed the general question time (not FMQs). Scottish Parliament will have the transcript up in the next day or two, though.
Sarah Boyack also has an interesting question this afternoon in Themed Questions:
"
To ask the Scottish Executive what work it is doing to improve the local environment around the canal network. (S4O-01136)
"Posted 13 years ago # -
Cheers - thanks all. @arellcat - sorry for misleading. you're quite right 9as usual)
Posted 13 years ago # -
I think there was a long standing issue at Sherrifhall due to potentially catastrophic subsidence if you start digging down into the ground around there and risk disturbing all the old and long-forgotten about shallow mine workings. Same issue would happen when driving piles to support a flyover. So any solution would be quite expensive.
Gogar is an underpass as they couldn't build a flyover that close to the end of the runways at the airport.
Anything that allowed pedestrians and cyclists to get over the horrible junction would be welcome. Currently you are expected to get off the bike and push. Much like the end of the Bypass at Gogar, it is assumed you will find your own way across through traffic slowing from / accellerating to 70mph, no lights, nothing to assist you in your journey.
Here's a photo from a 2004 CTC magazine of Sherrifhall roundabout illustrating the current "facilitities";
Same article says that Midlothian council awarded £1m in 1999 to build the pedestrian flyover and obviously sat on their hands and did nothing about it, despite getting the money! Article mentions Scottish Government at time saying it's all Midlothian's fault and there's nothing they could do about it.
It would be nice if key cycling routes were treated at a national level, like trunk roads, rather than at a local level where one incompetent council can cause things to fall through, allowing central Government to wash their hands of it.
Posted 13 years ago # -
The answer given can be summarised as follows:
"The upgrade of the Sherriffhall roundabout is identified as a priority for investment in draft investment 22 of the Strategic Transport Projects Review (http://www.transportscotland.gov.uk/strategy-and-research/publications-and-consultations/j11260a-05.htm#a22). However, these projects cannot be taken forward at present as the UK Government has cut the capital budget by 30%"
Posted 13 years ago # -
I have never cycled over Sheriffhall. However I suspect it would be okay as long as you know which lane to be in and that you maintain primary position in that lane. In some ways, due to the lights, it may be safer than other smaller roundabouts.
Going round the pedestrian route (which I have tried) is inherently much less safe as Kaputnik says.
My preferred route from Dalkeith to Cameron Toll would be using Gilmerton Road. For less confident cyclists you can cycle on the shared use pavement between Dobbies and the foot of Gilmerton (Drum)
Posted 13 years ago # -
@amir Trouble is, a lot of car drivers don't know which lane to be in, so there can be a fair bit of unexpected manoeuvring.
@kaputnik I think there will need to be some structural work done to enable the Borders Railway to get under the by-pass. Unfortunately, it's probably too far to the east of the roundabout to make it an attractive option for a cycle crossing connecting up to the A7 (if, indeed, such joined-upness of transport planning was possible).
Posted 13 years ago # -
"However, these projects cannot be taken forward at present as the UK Government has cut the capital budget by 30%"
This is a somewhat depressingly familiar response.
"We can't afford to do Good Things anymore because UKG cut all our budgets. <magical budget increase in about 2032> We can't afford to do all the Good Things we wanted to do before because our priorities must necessarily be focussed elsewhere in the current administration."
Did the answer given in the Main Chamber say anything about why grade separation was desirable?
Posted 13 years ago # -
Arellcat - no.
Posted 13 years ago # -
Arellcat - not so much as putting hairs on your chest and possibly causing your hair to turn white... it is a white knuckle ride most surely.
As I actually use this gyratory system quite a lot, best avoided if at all possible though, I cannot see why it is not possible to have a pedestrian/cycle sequence fitted in the traffic lights. One of the problems is that when you are waiting at side of any of one of the roads, it is not clear where the cars are going to come from as there are three filters that you can take if you come off the by-pass, immediate left to the Old Dalkeith Road, Millerhill, or continue on the by-pass, or even carry on all the way round to go towards Dalkeith itself or get onto the A7, this is from a car-driver's point of view, and also a great many motorists do not indicate so you miss the opportunity to cross. Also the lane segregation on the r/about itself is not clear if you are mad enough to cycle from the ODR to the ODR, which lane? It is a stramash but initially a ped/cycle phase at lights might make a difference.
Posted 13 years ago # -
"Did the answer given in the Main Chamber say anything about why grade separation was desirable?"
To make driving along the bypass faster? Presumably nothing to do with making access across the junction easier for pedestrians.
Grade separated junctions aren't necessarily much fun to cycle across either. E.g. Lothianburn which does not have the advantage of traffic lights.
"I think there was a long standing issue at Sherrifhall due to potentially catastrophic subsidence"
Presumably a foot/cycle bridge wouldn't be so problematic though.
Posted 13 years ago # -
Presumably a foot/cycle bridge wouldn't be so problematic though.
Absolutely not, it hasn't got to take the weight of a 44 tonne lorry doing 70mph!
Posted 13 years ago # -
I meant to say, if there is a ped/cycle sequence fitted to the lights can this mean that there are nice lights to indicate that this is the case, i.e. the martians may cross sign or a green bicycle...currently you have to guess whether or not it is safe to cross because there is nothing to indicate that as a cyclist/ped that you can go when using the supposed shared footpath option to get around the large obstacle that is SH roundabout!
Posted 13 years ago # -
It struck me as strange years ago that a council was going to get part of the cost for building a bridge to improve a trunk road junction instead of the Government paying all the cost. It also seemed to me that pedestrian and cycling facilities could have been built into the traffic signals. But having driven (not cycled) there, I've quite often see near misses due to drivers failing to realise which red lights they should stop for, and or changing lanes without checking for (or caring about) other traffic. So maybe at grade cycle/pedestrian crossings could put more vulnerable users at risk.
Posted 13 years ago # -
I can't imagine trying to cross other than by riding around in the lane (and even then, it's not very nice).
A rapid grade separated alternative could be good.
Posted 13 years ago # -
@slowcoach - I believe that had Edinburgh council decided to build the by-pass as M-way rather than a dual carriageway then funding comes out of a central pot from the Govt as part as the highways budget (this is central govt) but as they only built it as two-lane the councils are responsible for it's upkeep...so who was really clever then? Therefore any sort of crossing would have to council funded, and there was some money allocated for a bridge/flyover for bikes but the money got spent elsewhere and/or lost!
Posted 13 years ago # -
@Dave, I do prefer using the road too but you really do have to keep your wits about you and have eyes in the back of your head! It is dependent largely on whether I am solo or if I am with someone or others then I prefer to use the shared path, simply because others may not feel so confident using the road (and I can't say I blame them).
Posted 13 years ago # -
I have cycled it a couple of times, when the traffic was fairly light and it was OK.
Once I pushed my bike across the pedestrian route on the west side of the roundabout.
Getting across the east bound lane is fine as you simply cross once the traffic has stopped at red.
Getting across the entrance to the west bound bypass is not so nice as there aren't really any breaks in the traffic. You have to run for it.
Posted 13 years ago #
Reply
You must log in to post.
posts
