A417 Upgrade Reaches Key Milestone with New Shab Valley Underbridge

Work on the A417 Missing Link has taken a significant step forward as engineers begin installing giant concrete beams that will form the base of a new nine-lane underbridge at Shab Valley.

National Highways and its contractor Kier are lifting 53 pre-stressed beams, each weighing around 20 tonnes, into place.

Once complete, the 62-metre-long, 20-metre-wide structure will carry the upgraded A417 over a new junction, providing access for local residents, kennels, and factories while ensuring smooth traffic flow for vehicles joining from the A436 and B4070.

Concrete was chosen over steel as the construction material due to its efficiency and long-term durability. Using concrete beams reduces the need for heavy lifting equipment, cuts costs, and lowers health and safety risks on site. The bridge design also minimises future maintenance requirements and is tailored to withstand local environmental conditions.

Celine Acard, Senior Project Manager for National Highways, said the progress on the Shab Valley junction highlights the pace of delivery:“We’re really proud of the progress we’re making. This new junction will provide easy local access while keeping disruption for drivers to a minimum.”

Colin Fowler, Head of Highways at Tony Gee, the bridge designers, added:“By working with the natural topography, we’ve set the underpass into the valley, reducing both noise and visual impact. The integral concrete design means the bridge will last with only minimal maintenance.”

Once the beams are in place, five lanes of main A417 carriageway plus entry and exit slip roads will be built on top, with traffic due to switch onto the new alignment in early 2026.

Environmental and Engineering Achievements

The underbridge is the latest in a series of project milestones. Steel beams for the 42-metre Cowley Bridge have already been lifted into position, while a newly created meandering watercourse has been introduced as a sustainable alternative to culverts. Developed in partnership with the Environment Agency and ecological specialists, the stream is designed to enhance biodiversity, support aquatic habitats, and reduce flood risk.

Zeke Mensah-Kessie, Kier’s Environmental Manager, said:“This naturally designed stream improves water quality, supports wildlife, and reflects our commitment to sustainable construction.”

Ruth Clare of the Environment Agency praised the collaborative approach, calling the new watercourse “a well-designed environmental feature that protects nature while supporting development.”

Landscape-Led Approach

The £460m scheme is designed not just to improve transport links through the Cotswolds but also to leave behind a strong environmental legacy. Commitments include:

• Planting more than 130,000 trees and 80 hectares of calcareous grassland.

• Recycling excavated rock on site for road foundations.

• Creating wildlife-friendly features such as bat underpasses, bird fencing, reptile relocation, and hedgerow planting.

• Installing 7.5km of traditional drystone walls.

• Repurposing part of the old A417 into a green byway for walkers, cyclists, horse riders, and carriage drivers.

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With the new Shab Valley underbridge now taking shape, National Highways says the project is firmly on track to transform the A417 route while protecting and enhancing the surrounding environment.