A419 Blunsdon Bypass and Commonhead Bypass

The A419/A417 trunk road is a key route for traffic travelling between the M4 (Swindon) and M5 (Gloucester). In 2001 the Highways Agency proposed improvements to the Commonhead Junction, southeast of Swindon, and the village of Blunsdon, northeast of Swindon. An HA review investigated the problems of the A419 and found issues of traffic congestion, poor road safety and physical severance caused by the highway. The recommendations included a grade‚ separated junction at Commonhead and a western bypass for the village of Blunsdon.

The Post Project Opening Evaluation (POPE), commissioned by the Highways Agency, found that accident rates at the Commonhead Junction fell from an average of 20.7 per annum to 6.0 in the opening year, whilst travel time benefits were estimated to be worth £95.85 million over 60 years. Following the successful approval of the two schemes for funding by the Department for Transport, an Early Contractor Involvement (ECI) contract was awarded to Carillion Civil Engineering as principal contractor, which allowed Carillion’s consultants to assist with the refinement of the project design.

The integration of the highway into the landscape was at the heart of the project design process under the guidance of Nicholas Pearson Associates (NPA) as project landscape architect and environmental consultants. The role initially included undertaking assessments on alternative scheme options under the ‘Guidance on the Methodology for Multi¬'Modal Studies’ (GOMMMS). Two separate Environmental Impact Assessments (EIAs) were then undertaken, the scope of these assessments included: assessments of the landscape, ecology, archaeology, noise, water quality, and impacts on public rights of way. Consultation with statutory and non-statutory stakeholders, as well as the local community, through several public exhibition events, were also important to the scheme’s success, ensuring that concerns raised at an early stage were properly considered by the design team and solutions provided. High quality landscape design drawings and verified photo-montages were produced to help work through the design iteration during the EIA process and provide a resource for effective community engagement.

A number of specific issues and challenges had to be resolved through the design process. These included the integration of the highway into the wider landscape character and the mitigation of visual intrusion of the scheme into extensive views. This was achieved by the careful selection of the road horizontal and vertical alignments and the design of substantial soft landscape to roadside verges and embankments. These were designed as integrated greenways of native tree and shrub planting, species rich grassland and amenity grassland, which integrated with the existing landscape framework. In addition the presence of protected species including badgers, barn owls and bats required careful management to prioritise the avoidance of existing habitats, to relocate species (under licence from Natural England), and to provide new habitat connections.

NPA retained the role of Environmental Clerk of Works throughout the key stages of the scheme design and the construction phase. The role ensured that continuity was provided on all environmental matters and that the objectives defined by the Environmental Statement were realised on the ground.

Whilst Practical Completion of the two schemes was reached in March 2009, the aftercare of the landscape will continue, initially under a five year contract. NPA provides on'going inspection and monitoring of the planting works on behalf of the Highways Agency.