Drivers advised to plan A38 journeys ahead of Saltash Tunnel tidal flow switch-off

National Highways’ modernisation of the Saltash Tunnel is progressing towards the main phase of technology work.

The 37-year-old tunnel is undergoing a generational refurbishment scheme and the first phase of the Tunnel and Traffic Control System upgrade – including excavations, piling and concrete pouring – started in early January.

The programme has been progressing, initially under overnight eastbound closures and full tunnel closures throughout the spring, to enable excavation work for new gantries on the tunnel approaches.

Piling work has involved digging up to a depth of five metres on the approaches to the tunnel for the installation of four eight by nine-metre gantries, which will carry signs displaying live traffic and travel information.

The overhaul of the Tunnel and Traffic Control System technology was due to start later in the summer, but with the system detecting irregular faults in the traffic signalling, the traffic management for this phase of work has now been accelerated.

The current tidal lane traffic system has been switched off and in the meantime fixed lanes have been implemented for safety reasons until the new technology is installed and the scheme concludes this winter. The overhead lane control signals will remain lit until the gantries are powered down in the near future.

The tunnel has functioning safety systems and CCTV in place, and daytime traffic is now using two lanes westbound through the tunnel and on the Tamar Bridge and one eastbound lane through the tunnel and over the bridge with the cantilever link for local traffic and Tamar Tag holders.

As an additional safety measure, traffic signals have been installed at Tamar Bridge, the eastbound approach to the tunnel and the tunnel entrances. These lights are not in day-to-day use but will enable National Highways to close lanes in the event of a breakdown or incident.

During the ongoing overnight tunnel closures, traffic will continue to follow the standard B3271 and North Road diversion routes.,

As part of the scheme, 31 miles of copper cabling are being installed, alongside 12 miles of fibre cabling. These are being distributed away from cabinets inside the tunnel and into the west and east service buildings, which will ultimately reduce the need for future technological maintenance closures.

The tunnel upgrade represents further investment in the A38 in South East Cornwall, and the second phase – involving the changeover of technology systems and the installation and connection of the new gantries, signage, barriers and lighting – will continue through the summer and autumn months.

National Highways Tunnel Manager Julian Mitchell said: “We’re doing everything we can to minimise disruption for users of the tunnel and Tamar Bridge.

“We’ve implemented the new traffic management now for safety reasons, and have planned this carefully with our partners and have communicated the changes with all stakeholders.

“We appreciate the tidal flow switch-off will have an impact on people’s journey times, although our current monitoring, including the May Bank Holidays, suggests only slight delays.

“In the meantime, we advise people to plan ahead and allow extra time for their journeys, especially those from Cornwall into Devon, and thank drivers for their patience while the traffic management is in place for this extensive modernisation scheme to upgrade the tunnel technology and future-proof the structure for many years to come.”

The £25 million refurbishment scheme represents a significant investment in the A38 in South East Cornwall, and as part of the tunnel upgrade, the full programme includes:

·       Renewal of the tunnel control and traffic management system;

·       Fibre cabling as part of a modern electrical power distribution system;

·       Modernisation of the ventilation control system to manage air quality;

·       The replacement of existing sensors to improve air quality monitoring;

·       New, energy-efficient LED lighting;

·       The installation of traffic signals and automatic barriers to improve safety in the event of closures and emergencies;

·       Improved information signage and messaging;

·       Refurbishment of the water pumping systems;

·       the installation of easy-access cable duct covers.

In addition to the clearly signed directional lanes, a 30mph speed restriction will remain between the A38 Carkeel roundabout and the tunnel to ensure the continued safety of teams working on the scheme.

Mr Mitchell added: “We appreciate road closures can be frustrating but it’s difficult to work safely within and around the structure without closing it overnight.

“We have to keep the temporary speed limit in place during the day as it’s less safe for the workforce to deploy and remove on a daily basis. In the meantime, and until the new traffic control system is operational, we urge people to observe and adhere to the directional lane signage in place.”