Saltash Tunnel’s new control system goes live on Tuesday

After more than a year of cables, gantries and overnight closures, the moment Saltash drivers have been waiting for is almost here.

National Highways will switch on the new tidal flow lane control system inside the A38 Saltash Tunnel ahead of the morning rush on Tuesday, 19th May, marking the most visible step yet in the generational refurbishment of the 38-year-old structure.

The tunnel is the only one in Europe using a reversible tidal flow system, carrying between 38,000 and 40,000 vehicles a day and able to switch lane directions to manage traffic between Devon and Cornwall during peak periods. That bi-directional management was paused last May to allow the upgrade work to take place, and the new Tunnel and Traffic Control System is now ready to go live following off-site and operational testing in recent weeks.

📷Above, the complex cabling work inside the tunnel will connect and drive the new Tunnel and Traffic Control System, including lighting, ventilation, safety cameras and signage

What’s changing on Tuesday

When the system comes online, the westbound 30mph speed restrictions from Carkeel roundabout will be lifted and the limit returned to 50mph. A 30mph restriction will remain through the tunnel itself and along the B3271 and North Road overland diversion routes.

Julian Mitchell, National Highways’ Tunnel Manager, said the upgrade had been a long time coming.

“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,” Julian 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.

“We’ve done all we can to minimise disruption for local communities, and users of the tunnel and Tamar Bridge, we’ve been keeping all stakeholders informed every step of the way, and we thank people for their continued patience as we continue towards completion of the scheme.”

A year of work behind the scenes

Work began in early 2025 and has involved external excavation, the construction of new internal and external gantry signage, and the installation of 31 miles of fibre cabling as part of a modern electrical power distribution system.

The east and west service buildings have been refurbished, with original 1980s equipment stripped out and replaced with new electrical systems and LED lighting. A total of 226 adaptive LED lighting panels are being installed, 113 on each side, offering a 15-year plus lifespan compared to the four-yearly replacement cycle of the existing sodium lights.

Other improvements include four 5×9-metre external gantries and new internal messaging gantries, a modernised ventilation control system to manage air quality, replacement sensors for air quality monitoring, traffic signals to improve safety during closures and emergencies, and easy-access cabinets and cable duct covers.

What happens next

The scheme is expected to complete later this year following further signage and lighting installations and resurfacing work. Reduced Monday to Thursday overnight closures will continue in the coming weeks to allow the remaining work to be carried out safely.

“We appreciate the scheme has had some impact on road users and Saltash residents, and we have worked closely with our Tamar Crossings partners to minimise disruption,” Julian added.

“Once fully completed, the upgrade will reduce the number of maintenance closures, and in the meantime we thank all drivers and residents for their continued co-operation and patience.”

Further details and scheme updates are available on the National Highways A38 Saltash Tunnel page. Real-time travel information can be found on local radio, the @HighwaysSWEST feed on X, by calling the National Highways Information Line on 0300 123 5000, or at trafficengland.com.

📷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

📷Teams working overnight to install and connect new LED lighting systems in the tunnel