Introduction

On 14 February 2007, the Scottish Government gave its approval for the promotion of a replacement crossing over the Firth of Forth between the Lothians and Fife.
This announcement was made in response to ongoing concerns over the condition of the Forth Road Bridge. Intrusive investigations undertaken on behalf of the Forth Estuary Transport Authority (FETA) indicate that the main suspension cables supporting the bridge have suffered a significant loss of strength through corrosion.
The lack of certainty over the future of the Forth Road Bridge led to the commissioning of the Forth Replacement Crossing Study by Transport Scotland. An initial sixty five options were considered by the study. A sifting exercise eliminated options which did not meet National/Regional Planning Objectives or study objectives and those which were not technically feasible. The completion of this exercise resulted in five crossing locations being progressed for further assessment.
A detailed review of the remaining options identified a short-list of three corridors that were considered suitable for further study. These were taken forward for Scottish Transport Appraisal Guidance (STAG) Part 1 Appraisal. This appraisal measured the performance of each of the corridors available establishing the preferred form of crossing in each, a bridge or a tunnel. A development of the options recommended by the STAG Part 1 Appraisal led to a STAG Part 2 Appraisal being undertaken where each of the options carried forward was assessed against the Government’s transport appraisal objectives. Following the completion of this assessment and following a period of public consultation, the Cabinet Secretary for Finance and Sustainable Growth announced, on 19 December 2007, that the Forth Replacement Crossing would be a Cable Stayed Bridge in Corridor D upstream of the Forth Road Bridge.
In January 2008, Jacobs Arup Joint Venture was appointed as consultant to Transport Scotland to manage the delivery of the Forth Replacement Crossing Project.
Throughout 2008, Jacobs Arup has been engaged in the development of all aspects of the Forth Replacement Crossing Project, considering the proposed replacement bridge itself and the roads infrastructure associated with it.
This DMRB Stage 2 Corridor Report considers the roads infrastructure aspect of the project only. Its purpose is to establish the preferred route corridor north and south of the Firth of Forth.
For the purposes of DMRB Stage 2 assessment, the route corridor options discussed within this report have been considered over the full extents of the Forth Replacement Crossing study area. As a part of the next stage of design and assessment, further detailed consideration shall be given to the form and function of the junctions required and the extent of the optimal road infrastructure improvement provided within the preferred corridor. The developing design shall also reflect future consideration of the use of the Forth Road Bridge.