The generational upgrade of the A38 Saltash Tunnel will see a new tidal flow lane control system switched on next week.
National Highways started work in early 2025 on a major refurbishment scheme to bring systems in the 38-year-old structure up to modern standards, delivering significant traffic flow, safety and air quality benefits, while futureproofing its operating systems for many years to come.
Over the course of the past year, specialist contractors have completed external excavation work, along with the construction of new internal and external gantry signage and fittings, and the installation of 31 miles of cabling.
Recognised as the only tunnel in Europe using a reversible tidal flow system, the three-lane structure carries between 38,000 and 40,000 vehicles daily, and is able to switch traffic directions to manage traffic flows between Devon and Cornwall during the busiest times.
As part of the upgrade, the bi-directional management was switched off last May, and following rigorous off-site testing and operational testing in recent weeks, the new Tunnel and Traffic Control System is set to go live ahead of the morning peak time on Tuesday, 19 May, and in advance of the anticipated summer increase in vehicles.
Julian Mitchell, National Highways’ Tunnel Manager, said: “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.
“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.”
As part of the switch-on, the westbound 30mph speed restrictions from Carkeel roundabout will be removed and returned to 50mph, with 30mph limits observed through the tunnel and along the overland B3271 and North Road diversion routes.
Renewal of the tunnel control and traffic management system;
New, energy-efficient LED lighting;
Installing 31 miles of fibre cabling as part of a modern electrical power distribution system;
The installation of four 5×9-metre external gantries and new internal messaging gantries
Modernisation of the ventilation control system to manage air quality;
The installation of easy-access cabinets and cable duct covers;
The replacement of existing sensors to improve air quality monitoring;
The installation of traffic signals to improve safety in the event of closures and emergencies;
Improved information signage and messaging;
The installation of easy-access cable duct covers.
The latest work has involved refurbishment of the tunnel’s east and west service buildings, the stripping out of original 1980s equipment and the installation of new, state-of-the-art electrical systems and LED lighting.
A total of 226 adaptive LED lighting panels are being installed, 113 on each side of the tunnel, which will offer greater energy efficiency and sustainability – a 15-year plus lifespan compared to the four yearly replacement of existing sodium lighting.
Following some further signage and lighting installations and resurfacing work the scheme is expected to complete later this year.
In the meantime, traffic management – including reduced Monday to Thursday overnight closures – will continue in the coming weeks to enable the work to be carried out safely.
Mr Mitchell added: “We appreciate the scheme has had some impact on road users and Saltash residents, and we have worked closely with our Tamar Crossings partners/the Tamar Crossings team to minimise disruption.
“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.”
For further details and all the latest scheme updates, people can log on to https://nationalhighways.co.uk/our-roads/south-west/a38-saltash-tunnel-technology-upgrade/
And during the ongoing work, drivers can obtain up-to-the-minute travel information on local radio, the @HighwaysSWEST Twitter feed, by phoning the National Highways Information Line on 0300 123 5000 or by accessing the website www.trafficengland.com
