There was no mechanism to judge the cumulative magnitude of the road changes. The one-by-one closures of the routes from the east to the Harbour crossings best illustrated this - it never became clear that all convenient toll-free alternatives were being lost. The RTA carried out an extensive consultation process. However, the consultation was not inclusive enough to capture the depth of resentment that the road changes would bring about.
A robust assessment of the cumulative impact of road changes would have:
■ noted the strong impact of the tunnel on surface road traffic and amenities, and
■ assessed the risk of motorists deciding not to use the tunnel.