Transport projects – whether it's trams, pedestrianisation or low emission zones – are almost always controversial.
But take a look at these ones which were abandoned before they were implemented. You might think some, like the hovercraft perhaps, were good ideas. Others now seem bizarre, not least the mind-blowing 1949 Abercombie plan, which would have demolished swathes of the city centre to build an inner ring road.
They offer a fascinating insight into the priorities of the past – sometimes the quite recent past – and how much thinking has changed.
. Edinburgh Airport Rail Link (EARL)
The Edinburgh Airport Rail Link (EARL) would have involved building a tunnel under the main airport runway to bring trains to a station located underneath the terminal building. It was approved by the Scottish Parliament and scheduled to open in 2011. New sections of rail would be built to existing lines to allow regular trains from Glasgow, Fife and the north to call at the station. About £30m was spent on the scheme before MSPs agreed to scrap the scheme in 2007 - at the same time as they agreed to continue with the tram project. Photo: Ian Rutherford / Dan Phillips
. Hovercraft ferry from Edinburgh to Fife
In July 2007, Stagecoach ran a two-week trial of a hovercraft service between Portobello and Kirkcaldy. There were shuttle buses to the city centre and Leith. The service, called Forthfast, could carry 130 foot passengers at a time and proved popular with commuters and others. A total of 32,000 passengers made the 20-minute journey over the two weeks. Stagecoach was keen to carry the project forward and pledged to invest more than £10 million in two craft plus infrastructure, but the plans for a permanent route were sunk when Edinburgh City Council refused planning permission for a terminal. Photo: Neil Hanna
. Western Relief Road
This is the West Approach Road - originally known as the West Link Road - which opened in December 1974. But there was a much more ambitious and controversial scheme, the Western Relief Road, which would have served as a bypass for Corstorphine, running from the end of the M8, through Broomhouse and Stenhouse to connect with the West Approach Road. It was supported by the Tory administration on Lothian Regional Council but in 1986 they lost power to Labour who were pledged to scrap it. Alistair Darling, who became Labour's transport convener, later recalled: ""It was basically extending the M8 into Lothian Road. When we got elected, the contracts had been signed the day before the election and we ripped them up the day after, so it was never built." Photo: Alan Ledgerwood
. CERT/Fastlink guided busway
The City of Edinburgh Rapid Transport (CERT) guided busway project was the forerunner of the tram scheme - buses with guide-wheels running on segregated concrete tracks but able to run on normal roads as well. The route was going to run from the airport to the city centre, but only a short stretch was built in the west of the city - from South Gyle Access to Stenhouse - before it was abandoned. Named "Fastlink" and built at a cost of £10m, it opened in 2004 but closed just five years later to make way for the trams. Photo: Kenny Smith
1. Edinburgh Airport Rail Link (EARL)
The Edinburgh Airport Rail Link (EARL) would have involved building a tunnel under the main airport runway to bring trains to a station located underneath the terminal building. It was approved by the Scottish Parliament and scheduled to open in 2011. New sections of rail would be built to existing lines to allow regular trains from Glasgow, Fife and the north to call at the station. About £30m was spent on the scheme before MSPs agreed to scrap the scheme in 2007 - at the same time as they agreed to continue with the tram project. Photo: Ian Rutherford / Dan Phillips
2. Hovercraft ferry from Edinburgh to Fife
In July 2007, Stagecoach ran a two-week trial of a hovercraft service between Portobello and Kirkcaldy. There were shuttle buses to the city centre and Leith. The service, called Forthfast, could carry 130 foot passengers at a time and proved popular with commuters and others. A total of 32,000 passengers made the 20-minute journey over the two weeks. Stagecoach was keen to carry the project forward and pledged to invest more than £10 million in two craft plus infrastructure, but the plans for a permanent route were sunk when Edinburgh City Council refused planning permission for a terminal. Photo: Neil Hanna
3. Western Relief Road
This is the West Approach Road - originally known as the West Link Road - which opened in December 1974. But there was a much more ambitious and controversial scheme, the Western Relief Road, which would have served as a bypass for Corstorphine, running from the end of the M8, through Broomhouse and Stenhouse to connect with the West Approach Road. It was supported by the Tory administration on Lothian Regional Council but in 1986 they lost power to Labour who were pledged to scrap it. Alistair Darling, who became Labour's transport convener, later recalled: ""It was basically extending the M8 into Lothian Road. When we got elected, the contracts had been signed the day before the election and we ripped them up the day after, so it was never built." Photo: Alan Ledgerwood
4. CERT/Fastlink guided busway
The City of Edinburgh Rapid Transport (CERT) guided busway project was the forerunner of the tram scheme - buses with guide-wheels running on segregated concrete tracks but able to run on normal roads as well. The route was going to run from the airport to the city centre, but only a short stretch was built in the west of the city - from South Gyle Access to Stenhouse - before it was abandoned. Named "Fastlink" and built at a cost of £10m, it opened in 2004 but closed just five years later to make way for the trams. Photo: Kenny Smith