Can you build a road and improve biodiversity?

The project is called the Missing Link because it will turn the A417’s only remaining section of single carriageway into dual carriageway. The single carriageway section currently causes regular bottlenecks, leading to slow-moving traffic in and out of Gloucester.

According to Kier, the main contractor on the project: “The Missing Link is a 3.5-mile stretch of road that causes problems for road users and those who live and work in the area. This includes congestion and safety concerns with poor visibility and other factors meaning that accidents occur frequently on this section of road.”

This assertion is backed up by data that shows a consistent number of accidents and casualties occurring each year between 2013 and 2018.

The problems it creates spills over to neighbouring areas too. A Highways England scheme assessment report in 2019 stated: “Delays of 20 minutes or more are not unusual, and nor is the sight of queuing traffic or the sound and smell of idling engines. Some motorists divert onto smaller local roads to avoid tailbacks, causing difficulties for neighbouring communities.” 

As well as creating the second lane, major earthworks have taken place to reduce the incline of the hill between A46 Brockworth Junction and The Air Balloon Roundabout from 10% to 8% – to create a gentler and safer approach. 

Matthew Talliss FRICS, Senior Commercial Director at Arcadis, believes a scheme like this can still come out ahead on nature. “Adding capacity to a major road network inevitably will have environmental impacts that include embodied carbon, land that needs to be taken over and the potential for additional traffic,” he says. “However, with robust environmental assessment, implementing biodiversity net gain and sustainable design principles, it’s feasible for a road improvement scheme to deliver enhancement of biodiversity compared to its baseline position.”

Celine Acard is the senior project manager for the A417 Missing Link at National Highways. She says they worked with a number of other organisations to overcome the “unique challenges” presented by the scheme.

“We worked closely with Gloucestershire County Council, National Trust, Gloucestershire Wildlife Trust, Cotswolds National Landscape and Natural England before even starting the construction phase, to maximise the environmental benefits, create new habitats and improve biodiversity in the area.”

For example, some trees and vegetation were removed when work first began in 2023, but 42,000 new trees have been planted so far with plans for a further 80,000, including oaks, holly, field Maple, hawthorn and yew.

A ‘green bridge’ called the Gloucestershire Way crossing is 60m long and 37m wide and will provide a multi-purpose crossing point for animals, walkers, cyclists, and horse riders to use.

“We are very proud of the ‘green bridge’ and aim to double the number of them across the road network within the next few years,” says Acard. “We have been increasingly working directly with organisations in the conservation sector, including charities and small businesses, and many of these projects have prioritised nature-based solutions, practices which involve working with nature to address climate and human-induced impacts.”

In addition to the green bridge, around 4.6 miles of new drystone walling running alongside the road “will preserve the traditional landscape character”. 

For Talliss, that ambition should be the baseline for any modern scheme. “Modern infrastructure projects must demonstrate more than the ability to deliver on time, on budget and to the required standards,” he says. “They have a responsibility to create a legacy via long-term benefits for the local communities, which means consideration of social value, biodiversity, sustainability, accessibility and economic opportunities for local people.”

Alex Thomson, from Oxford Cotswold Archaeology told the BBC: “It's clear that the structures we've recorded helped serve the passing trade on a busy Roman highway; it really could be a 2,000-year-old service station.” Roman roads built at the time connected their settlements and allowed for greater trade, transport and movement of supplies. 

But how did the A417 project team coordinate with the archaeological team who were there to look for Roman artefacts? “We worked closely with Historic England and Gloucestershire County Council to design a scheme that avoids and prevents impacts on the historic environment,” says Acard. 

“We’re also protecting and preserving historically important sites during construction. Among the findings are a Roman Cupid figurine, pottery, coins and jewellery, dating from as far back as the Mesolithic era (approximately 9,600 BC to 4,000BC). They have been recorded and are going to the Corinium Museum in Cirencester.”

Asked what he would add if budget were no object, Talliss sets the bar high. “I’d love to see it become far more than a major road upgrade: a project focused on leaving a legacy, with restoration of nature, enhanced biodiversity, active travel and renewable energy that supports local employment and strengthens the local community,” he says. “That would mean new woodland, ponds linked to existing habitats, wildlife bridges, maximising recycled and low-carbon materials, electrifying the construction plant and designing for 100 years to be resilient to climate change.”