This is the final report on the project planning work carried out during 2008. It summarises the work carried out to date and explains the project development through its key stages as summarised below:
- The Government’s decision in December 2007 on the scope of the Forth Replacement Crossing Project to provide an independent replacement bridge was based on prognosis at that time that the functionality of the existing bridge would be extremely limited. The project was estimated to cost between £3.2bn and £4.2bn at outturn completion in 2016.
- An undertaking was provided to the Scottish Parliament Transport, Infrastructure and Climate Change Committee (TICC) in January 2008 that, should the prognosis for the existing bridge improve, further consideration would be given to what any future long term role might be for the existing bridge in supporting the crossing capacity over the River Forth.
- A review of the route options undertaken between January and August 2008 (reference Sections 3 and 4) identified that improvements should be based on the road corridors utilising the A90/M90 north of the Forth (North Corridor Option 1) and the M9 Spur south of the Forth Road Bridge (South Corridor Option 1).
- Continued appraisal of the condition and potential of the Forth Road Bridge (reference Section 5) has provided confidence that the existing crossing can make a contribution to the project. It is not capable of meeting the future needs as the main crossing but can support future public transport requirements and accommodate non-motorised users (pedestrians and cyclists).
- The opportunity to use the Forth Road Bridge in this way has allowed the development of a flexible, narrower replacement bridge of high quality and significantly reduced cost.
- The connecting road strategy looked initially at expanding capacity through additional road width prioritised for high occupancy cars (cars with more than 1 person). Given that this strategy carries the risk of overprovision for residual single occupancy vehicles, particularly during the peak commuting periods, and traffic management inefficiencies, a more focussed assessment was made of the connecting road provision.
- Analysis of traffic conditions indicates that peak period congestion is largely a factor of the close junction spacing along the A90/M90 corridor and driver reaction to that, rather than the inadequacy of a dual two lane motorway. It is proposed that this is addressed by the use of Intelligent Transport Systems with local junction improvements. This strategy contributes a further cost saving against the original project estimate.
- The revised scheme cost estimate is between £1.72bn and £2.34bn (see Section 8), an overall reduction of broadly £1.7bn in cost compared to the previous proposal.
- The economic parameters have changed over the period. The improving prognosis for the Forth Road Bridge has meant that the economic base case assumes its repair rather than closure (see Section 10). The assessment takes into account the restricted use of the crossing over an extended period to allow for repair and refurbishment including the replacement or augmentation of the existing cables. The revised assessment confirms the emerging project as a sound investment, but with benefits at a reduced level reflecting the revised base case.
- The construction of the recommended scheme has a lower environmental and carbon footprint in relation to embedded carbon, reflecting the maximised use of existing infrastructure, and better supports the development of public transport.
- The Managed Crossing Scheme offers opportunities for complementary measures by local transport authorities which can address scheme and wider objectives. These include potential improvements to existing facilities for bus priority and to promote sustainable transport practices. The principal facility close to the crossing is Ferrytoll Park and Ride. This may be complemented by further Park and Ride or Park and Choose facilities at Halbeath and Rosyth. There is also an opportunity for the local transport authority to develop a further new Park and Ride facility at South Queensferry, south of Echline Junction.