Look at A30 Chiverton to Carland Cross upgrade in Cornwall

This week, the government company has been celebrating the recent completion of the scheme, which opened to traffic in June.

Local representatives, including MPs, have been at the site while the engagement team has been out about.

Here National Highways takes a look back at the past four years of work and what it has achieved:

The completion of the scheme means the only remaining stretch of single carriageway on the A30 between Camborne and the M5 at Exeter has been removed, providing significantly reduced travel time and cutting congestion in time for the summer holidays.

The upgrade can trace its history as far back as 1989. With ever-increasing traffic flows and no real alternative routes, journeys on this part of the road were regularly delayed, and congestion often brought traffic to a standstill, even outside of the tourism season.

An aerial view of the new Chiverton Junction (Image: National Highways)

Plans to increase capacity on the route were developed and between 2015 and 2018, consultations took place in the area with a significant majority of respondents supporting improvements. Work was due to begin in 2020 however due to the Covid-19 pandemic, main construction did not begin until 2021.

The scheme

Throughout the duration of the project, 8.7 miles of new high-quality dual carriageway has been built, replacing the existing single carriageway, which will be de-trunked as the B3285/B3288 and handed over to Cornwall Council as a slower road for local traffic.

The map below shows the new and old route of the A30:

(Image: National Highways)

The western end of the project begins at Chiverton Cross roundabout, where ‘Chivvy’ roundabout, Cornwall’s worst accident hot-spot, has been removed. 

This has been replaced with a new flyover and roundabout, separating long-distance and local traffic.

A new footbridge has also been installed to provide a safe crossing for pedestrians, cyclists and horse riders. The bridge aforms part of the Saints Trails route linking St Agnes and Threemilestone and you can find out more about this route further down the page.

Travelling east, we approach the new Chybucca junction, allowing for north-south access across the A30. Continuing along the route, there are a number of new underpasses and overbridges including the Marazanvose green bridge.

An aerial view of the newly opened road (Image: National Highways)

Formed with two decks and planted extensively with plants and hedging, the bridge will maintain and enhance connectivity for habitats separated by the new road, providing a flourishing green border and providing a safe passage across the road for badgers, voles and other small animals, insects and birds.

Travelling further on we reach Tolgroggan Bridge, which has been completely replaced with a new structure to accommodate the width of the new dual carriageway and the existing road.

Reaching the eastern end of the scheme, the junction at Carland Cross has been upgraded, with a new interchange and flyover.

Challenges

Since the start of construction, the programme of work had to adapt to the effects of both the pandemic and growing weather challenges.

Between January 2021 and August 2023 there were 14 Met Office classified storms and since August 2023 there were an unprecedented total of 10 storms affecting Cornwall.

The road was officially opened on June 24, 2024 with the first cars making their way along the new dual carriageway shortly before 6am that morning

Investing locally

The opening of the new A30 will not only relieve congestion and improve journey reliability times, but also unlock economic growth in the region by supporting business, employment and residential development opportunities.

Through the introduction of a dedicated education, employment and skills coordinator, National Highways has worked with schools, colleges, universities and Jobcentre Plus, directly or indirectly supporting hundreds of local jobs.

It has also supported local manufacturing in a number of ways:

• China clay residue, a by-product of the industry known as stent, would normally have no use and be left in white spoil heaps. Instead, the material from the Littlejohns Pit, near St Austell, is being processed into sustainable secondary sand and aggregate, not only reducing embodied carbon, but also saving on the transport carbon cost.
• Aggregate Industries invested more than £4 million in the nearby Melbur Quarry at St Stephen to produce more carbon-friendly warm mix asphalt for the new road surfacing. Fully approved by National Highways, warm mix asphalt is a greener process that has less impact on the environment, with reduced hydrocarbon emissions and greenhouse gases. Due to its lower temperature, it is also safer for construction workers to use.
• Local company Cornish Concrete Products provided a pre-cast section of the new Marazanvose bridge

The newly-opened A30 dualled stretch (Image: National Highways)

Aside from the aggregate and asphalt production, local skills and supplies have been supported by:

• employing site managers and engineers from the local area
• using Devoran Metals for reinforcement on the project
• the daily use of a local scaffold supplier
• using smaller suppliers of timber products
• engaging with local colleges and the Camborne School of Mines.

In the community

Throughout the duration of the project, National Highways worked closely with local residents and businesses to help make a difference to the local community.

It also raised more than £30,000 for charitable organisations by carrying out a number of events and taking part in a skydive!

A total of £1,400 was donated to Nansledan School’s environmental project. The funding has allowed the school to acquire a range of resources from Waterhaul, a Cornwall-based company that utilizes recycled litter from our oceans. 

Protecting the environment

One of the main objectives was to protect the environment, minimising impacts and, where possible, delivering enhancements to boost biodiversity in the area.

National Highways helped deliver a sustainable project by:

• planting species-rich grassland at specific locations
• using low-carbon construction methods
• carefully landscaping new ponds to provide habitats for wildlife
• using solar-powered tower lights to reduce noise and air pollution

As part of its Designated Funding programme, the company provided Cornwall Wildlife Trust with more than £1 million to help restore and recreate more than 15 hectares of woodland, orchard, grassland and heathland around Ladock to Gwills and Benhaven to Lambourne Mill, north of Truro.

It was part of the Green Ribs projects, which will create vitally important habitats down the spine of Cornwall.

(Image: National Highways)

As part of the environmental initiative, a total of 15,000 trees have been planted within the mid-Cornwall landscape, including species such as Scots pine, oak, lime, chestnut, sycamore and blackthorn near Idless Woods, Truro.

The scheme has a 20% biodiversity net gain, helping it to provide lasting and vital habitats for wildlife for years to come.

All landscaping uses native vegetation found in the local area to encourage wildlife and provide a green corridor linking the scheme to adjacent protected habitats.

Along with long-lasting benefits for biodiversity, the scheme also sought to improve access for walkers, cyclists and horse-riders.

One of ten underpasses and overbridges along the route, the Chiverton footbridge, which opened earlier this year, was designed with sustainability at its heart while also providing a safe route across the A30.

The bridge forms part of the Saints Trail, an 8km route from St. Agnes to Truro, with another 4.5km trail between Perranporth and Goonhavern.

The multi-use trail, funded by our Designed Funding programme, opened in 2023 and is designed for both leisure and commuting. It follows the former Perranporth to Chacewater railway line, which closed in 1963.

The future

With the summer season upon us, National Highways hopes opening the road ahead of the school summer holidays will make a significant and positive difference to the journeys of visitors, local communities, and businesses.

And although work is still being carried out over the coming months to complete structural, landscaping and other ancillary work, local motorists and residents are already benefitting from shorter journey times.

The company said: "We’d like to thank the people of Cornwall for the patience since construction of the project started back in 2020.

"Now our work is complete, this vital upgrade will make a significant and positive difference to the journeys of visitors, local communities, and businesses, not just this year but well into the future."

Top five facts about the scheme

• The new Tolgroggan Bridge weighs 275 tonnes – the equivalent of 900,000 Cornish pasties!
• More than 2.6million cubic metres of earth was moved in carrying out earthworks
• Nearly 29 miles of highway drainage have been installed
• Teams planted 150,000 trees and 4.5 hectares of new woodland
• 650 staff were working on site at its peak, more 4,000 over the life of the project