As the Designer we needed to ensure that we could provide a design that would meet the Highways Agency scheme objectives to improve safety and relieve the heavy congestion the A19/A1058 Coast Road junction faced each day which totals some 69,000 vehicles passing through the junction.
Our design proposals included: The A19 to be realigned to pass beneath the existing grade separated junction, with new slip roads created off the existing A19 roundabout linking to the newly aligned A19. A new traffic signal control installation will be implemented to improve capacity and safety and we will also enhance facilities for non-motorised users at the junction.
We were appointed to the scheme through the Highways Agency project support framework and were brought on at stage 3 of the project control framework (PCF), preliminary design. We challenged the original design proposals from PCF stage 2 to deliver a more cost efficient solution. One aspect of this was to improve on the safety of the scheme during construction, maintenance and operation as well as considering the affordability and economic return.
We worked collaboratively with the HA, stakeholders and local community to create a revised design, a process that reduced the cost of the scheme by 25%, for which we were highly commended by the HA’s commercial advisors. We have subsequently scored 10/10 in our August/September motivating success toolkit (MST) scores making us the first supplier through the PSF framework to have ever scored a ten for ‘Product.’ Look out for more on the intranet.
Our revised design strategy resulted in a change to the planning of the construction phase with the existing A1058 bridges at the A19 roundabout being retained instead of being replaced, removing the need for a new multi span bridge, including a new single span structure over the realigned A19. The design strategy both improved the health and safety during construction, and saved 14 months (33%) from the original 42 month construction programme.
We also adopted an urban cross section for the new A19 mainline and slip roads providing continuity with sections of existing A19 immediately adjacent to the scheme. This in turn reduced the width of the proposed mainline A19 cross section by 20% and reduced the environmental impacts.
A number of elements were also introduced to enhance safety for road workers and users, including concrete central reserve barriers, a traffic management signing system, slip road lane over provision and widened verges.