Despite significant investment and maintenance since it opened in 1964, the Forth Road Bridge (FRB) began to show signs of significant deterioration in the early years of the 21st century.
In 2004, an internal inspection of the main cables found that corrosion had resulted in a loss of strength of between eight and ten per cent, giving rise to fears that significant traffic restrictions might be required in future to allow for repairs. At that time some 70,000 vehicles used the bridge every day and it was one of the most vital economic arteries in Scotland. Given these issues and the potential impact of major maintenance works, the FRB was no longer deemed viable as the long-term main crossing of the Firth of Forth.
In 2006-7, Transport Scotland carried out the exhaustive Forth Replacement Crossing Study – part of the wider Strategic Transport Projects Review – to examine a wide range of options for replacing the FRB. These included suspension and cable-stayed bridges and different types of tunnels in a variety of different locations.
Responding to the study in December 2007, Scottish Ministers announced their intention to safeguard the economically vital cross-Forth transport corridor by building a new cable-stayed bridge to the west of the current FRB by May 2017. This challenging timescale was necessary due to the potential need for future restrictions to Heavy Goods Vehicles using the FRB.
On 8 June 2016, it was announced that completion of the Queensferry Crossing, by the challenging target date of the end of 2016, was no longer possible, however, the contractor has said they aim to open the Queensferry Crossing in May 2017.
Transport Scotland immediately began design, procurement and statutory work on the fast-tracked scheme – appointing the Jacobs Arup joint venture as design consultants in January 2008. An extensive programme of regular engagement and consultation began with a wide range of affected communities and interested parties to inform the development of the project. A number of key improvements were made to the design as a result of feedback from local communicates, notably the location of the South Queensferry Junction being moved further to the west of the town, significantly reducing local impacts.
In December 2008, Scottish Ministers announced the innovative Managed Crossing Strategy which allowed the budget for the project to be significantly reduced.
The main feature of the strategy was ensuring the existing Forth Road Bridge (FRB) infrastructure would be retained and become a dedicated public transport corridor carrying buses, pedestrians and cyclists. Retaining limited use of the FRB in this way will reduce the weight of traffic on it and therefore extend the operational life of the bridge.
This approach immediately delivered a saving of over £1.7 billion on the scheme's original estimated cost of £3.2 to £4.2 billion, which was based on a much wider replacement bridge including dedicated public transport lanes as well as a dual carriageway plus hard shoulders.
The managed crossing strategy dramatically reduced the total cost of the FRC project to between £1.4 and £1.45 billion as announced in Autumn 2013, with a further saving of £50 million announced in October 2014 - bringing the project estimate down to between £1.35 and £1.4 billion.
The Forth Crossing Bill was introduced in the Scottish Parliament in November 2009, the same month as the procurement process – one of the biggest the Scottish Government had ever undertaken – got under way.
Following extensive Parliamentary scrutiny throughout 2010, the Forth Crossing Act was granted Royal Assent in January 2011.
The current budget range for the project is £1.325 - £1.35 billion, releasing £245 million worth of savings since construction started in June 2011.