Students' 'throughabout' pitched as cheaper cue for notorious Edinburgh junction
‘Similar junction layouts have been trialled elsewhere in the UK’ - Tom Aitchison, M.Eng civil engineering student
The Scottish Government is being urged to look seriously at an alternative solution for Edinburgh's notorious Sheriffhall roundabout drawn up by students at Heriot-Watt University.
Official plans for a flyover to relieve regular traffic jams at the most congested junction on the City Bypass have never made it off the drawing board despite funding being allocated for the project as long ago as 2017.
But earlier this year civil engineering students at Heriot-Watt came up with the alternative idea of a “throughabout”, a junction layout that allows some bypass traffic to pass through the centre rather than circulating around the roundabout.
And now Edinburgh council's transport and environment committee has agreed to write to new Transport Secretary Stephen Flynn, urging him to give "careful consideration" to the innovative scheme.
Although the students' work is not a fully costed proposal, a throughabout would be less expensive than a flyover.
The 2017 Edinburgh and South East Scotland City Region Deal included cash to upgrade the Sheriffhall junction and a flyover was unveiled as the preferred option. Plans were paused in 2020 for a review of the project following a Scottish Government budget deal with the Greens.
A public local inquiry was eventually held in early 2023 and the report delivered to the Scottish Government in early 2024, but repeated questions in parliament have met with the answer that the report is still being reviewed by officials.
The Heriot-Watt students surveyed more than 400 residents and commuters about the roundabout as part of their study and found that 65 per cent of respondents reported difficulty accessing key services including healthcare and employment.
Tom Aitchison, M.Eng civil engineering student at Heriot-Watt, said: “What the throughabout allows for is an increase in traffic flow by letting the main traffic on the bypass pass straight through the middle of the junction rather than having to stop and go round.
“Similar junction layouts have been trialled elsewhere in the UK, which helped inform our thinking as we explored how different design approaches could work in a Scottish context.
“What inspired us was hearing from the people who use this road every day. It was very evident from the start that the roundabout experienced high congestion levels, but we didn’t expect people to feel quite so passionately about it.
“The responses gave us a lot to work with and made sure we kept the real-world impact of our work front and centre throughout.”
And Dr Shadi Mohamed, associate professor at Heriot-Watt's School of Energy, Geoscience, Infrastructure and Society, said the students did not stop at conceptual ideas.
“They developed full technical solutions, shaped through engagement with relevant stakeholders and grounded in real-world feasibility.
“They took a rigorous and thoughtful approach from the outset. They assessed multiple sites across Edinburgh, identified Sheriffhall as the location where intervention would make the greatest difference, and built a strong evidence base from there.
“They ran detailed traffic simulations under higher-than-current forecast demand, tested their design against modern highway standards, and worked through everything from foundation engineering to sustainable drainage and carbon reduction, achieving a twelve per cent saving in embodied carbon through careful material choices and local sourcing.”
The students selected a low-carbon concrete produced just 10 minutes from the site, cutting the material’s carbon footprint by 50 per cent.
Recycled plastic and reclaimed aggregate were used in place of traditional materials, reducing emissions without compromising performance.
And in order to manage polluted surface water runoff, the students designed a new wetland and pond system around the Dean Burn, to filter and treat water before it reaches the burn, while also creating new habitat and providing flood storage for the surrounding area.
Conservative councillor Neil Cuthbert, who proposed the motion at committee, praised the student’s work and said their scheme deserved serious consideration.
He said: "I’m not an expert, so I don't know if it's the best option, but it's worth considering and it’s an important contribution to the debate. I think we should recognise that these students have put a lot of work into this and it's worth having a serious look at it.
"Heriot-Watt has already done work on the prospect of tram trains on the South Suburban line, so they are doing important thinking about what the transport system in Edinburgh could look like.
“As I understand it, the main advantage of a throughabout is that, whereas with a normal roundabout all the traffic has to go round it, a throughabout means the traffic wanting to bypass Edinburgh can go through it rather than round it.
"So there is a delay, because there are traffic lights, but it’s not as disruptive, and it's not as expensive as a flyover.”