A21 Tonbridge to Pembury dualling

Balfour Beatty created a new dual carriageway and flyover to speed up journeys, improve safety and boost the local economy – benefitting over 35,000 drivers a day

The project involved a series of complex improvement works designed to increase capacity and enhance traffic flow, including:

  • Widening the A21 to a dual carriageway

  • Constructing two new junctions

  • Delivering a new flyover to reduce congestion and improve journey times

Together, these upgrades have significantly improved resilience and safety on the route for all road users.

Delivering in a sensitive environment

The scheme was delivered within an Area of Outstanding Natural Beauty, with significant cultural and ecological heritage. Our teams used state-of-the-art technology and extensive highways expertise to ensure the project was delivered safely and with minimal environmental impact.

Innovative Microsoft HoloLens mixed-reality technology was used to support the design of a new footbridge. This allowed stakeholders to visualise the asset before construction began, helping to identify potential challenges early and improve design outcomes.

35,000

drivers a day

23

opportunities for the next generation

9 hectares

translocated woodland

Increasing biodiversity and protecting habitats

Environmental protection and biodiversity enhancement were central to the project’s delivery. Works were carried out to the highest environmental standards, safeguarding the protected countryside surrounding the route.

Key measures included:

  • Carefully relocating ancient woodland and seed-rich topsoil to a nearby area using specialist techniques, preserving the site’s ecological makeup

  • Creating new areas of heathland to enhance biodiversity

  • Installing six-metre-high temporary bat fencing to guide bats safely across the new road while planting became established

  • Delivering 900 metres of environmental noise barrier fencing

  • Constructing four new wildlife ponds

In addition, an ancient barn was carefully dismantled and is being reconstructed and preserved at a heritage museum, ensuring its long-term protection.

Creating social value for local communities

Throughout the project, Balfour Beatty focused on delivering meaningful social value alongside infrastructure improvements.

The scheme created:

  • 11 graduate placements

  • Five apprenticeships

  • Six work experience placements

Our site team also engaged with the local community, helping more than 200 schoolchildren understand road safety through educational talks at nearby schools.