MOTORISTS will start to see light at the end of the Saltash Tunnel after months of works as National Highways prepares to switch on a major new tidal flow lane control system next week.

The milestone marks a significant step in the long-running upgrade of the A38 Saltash Tunnel, with the new Tunnel and Traffic Control System set to go live ahead of the morning rush hour on Tuesday, May 19.

The huge refurbishment scheme began in early 2025 and is designed to modernise the 38-year-old tunnel with upgraded technology aimed at improving traffic flow, boosting safety and enhancing air quality for thousands of motorists travelling daily between Cornwall and Devon.

The Saltash Tunnel is believed to be the only tunnel in Europe operating a reversible tidal flow system, allowing lanes to change direction depending on traffic levels. Around 38,000 to 40,000 vehicles use the route every day.

A total of 31 miles of fibreoptic cabling is being installed and connected to power the tunnel’s control systems, including the tidal flow lane control, lighting, fans and cameras
A total of 31 miles of fibreoptic cabling is being installed and connected to power the Saltash tunnel’s control systems, including the tidal flow lane control, lighting, fans and cameras (National Highways)

As part of the upgrade, the bi-directional system was temporarily switched off last May while engineers carried out a major overhaul of the tunnel’s ageing infrastructure and operating systems.

During the past year, teams have completed excavation works, installed four large external gantries, fitted new internal signage and laid around 31 miles of fibre optic cabling throughout the tunnel.

Julian Mitchell, National Highways’ Tunnel Manager, said the improvements were essential to futureproof the crossing.

“Our systems have been operating for 20-plus years so it’s essential that we make the tunnel fit for now and for the future,” he said.

“The tunnel and the tidal flow corridor – operating in tandem with the Tamar Bridge control room – rely on specialised technology and we’re now nearing the completion of this generational upgrade, one which has presented a significant challenge and involved a complex operation.”

He added: “We’ve done all we can to minimise disruption for local communities, and users of the tunnel and Tamar Bridge, and we thank people for their continued patience.”

The new Saltash tunnel and traffic control system, including lighting, ventilation, safety cameras and signage
The new Saltash tunnel and traffic control system, including lighting, ventilation, safety cameras and signage (National Highways)

The return of the tidal flow system will also mean changes for drivers approaching the tunnel from Cornwall. The westbound 30mph speed restriction from Carkeel roundabout will be removed and restored to 50mph, although 30mph limits will remain through the tunnel itself and along diversion routes including the B3271 and North Road.

The project includes a range of upgrades aimed at improving both efficiency and safety, including new LED lighting, enhanced ventilation systems, upgraded safety cameras, replacement air quality sensors and improved digital signage.

A total of 226 adaptive LED lighting panels are being installed inside the tunnel, replacing older sodium lighting systems that required frequent maintenance. National Highways says the new lights are expected to last more than 15 years.

The works have also involved refurbishing the tunnel’s east and west service buildings and removing original equipment dating back to the 1980s.

Although the switch-on represents a major milestone, overnight closures and traffic management measures will continue in the coming weeks while resurfacing and final installations are completed safely.

National Highways expects the full scheme to finish later this year.