This issue has doubtless arisen before but most recently a HIRA member wrote to Cllr. Clare Satchwell cc Cllr. Wilson, proposing a possible solution to the A3023 traffic problem on Hayling. The reply dated April 6th with detailed explanation eventually came directly from David Hayward, Planning Policy Manager for HBC. As this is of public interest, the key elements are in the section of David's reply to the HIRA member below.
I also just wanted to let you know that, far earlier in the process, a very large list of potential transport mitigation solutions were explored. This certainly included your suggestion of a direct link from Hayling to Eastney, either via a tunnel or a bridge. We did look into this but it wasn’t taken forward into the original Hayling Island Transport Assessment or the addendum for the following reasons (not in any particular order):
All public infrastructure has to demonstrate a positive benefit:cost ration (BCR), ie that the benefits that it brings outweigh the costs of providing it over the lifetime of the asset. Proposals for a tunnel between Gosport and Portsmouth failed on the basis of BCR. Whilst the link to Gosport was not intended to be vehicular, it is not considered that a benefit BCR would exist for a link to Hayling given the very high cost. The geology of the area would require a ‘cut and cover’ rather than bored tunnel. This requires more engineering and hence more expense. Due to the depth of the harbour channel and in order to meet acceptable gradients in the tunnel, the portals would be some way removed from the actual coast – we estimate an overall tunnel length of 1.25km would be required.
Any such operation requires a considerable area for supporting the actual tunnel construction activity. The land required is more than just the ends of the tunnel, it is the site compound and everything that goes with it. On both sides of the Harbour, such space (25+ hectares) is not available due to environmental or archaeological designations as well as the lack of availability of physical space (particularly on the Portsmouth side). Even with a similar layout to the Itchen Bridge, the toll area one end would again require a considerable land area which is not available.
impacts of such a connection would be significant. There would be a need for other changes as a result, including changes to properties. There are also likely to need to be changes on the Portsmouth side of the harbour as well. For information (and interest) though, attached is a map from the 1970s showing a potential proposal at that point to provide a similar scheme as part of a wider transport policy for the city, some of which came to fruition, but not all by some margin (particularly on the eastern side).
Providing a second means for Hayling Islanders to access Portsmouth also has a corollary: it would also be a fourth road access in and out of Portsmouth. Even with a toll, such a provision would have a significant attraction, particularly if heading east towards Chichester and Brighton and so result in many more traffic movements. If it were enacted comprehensively, with a package of transport measures along the A3023 to improve the link to Langstone and the A27, the inevitable impact would be more pressure for development on the island than exists at this point as well.
I certainly appreciate your concerns regarding the impact of development and your views regarding a direct link to Eastney. I did just want to reassure you that this has been considered and not taken forward for good reasons.
All the best
Planning Policy Manager
Planning Services, Havant Borough Council, Public Service Plaza, Havant, PO9 2AX