IN Brief:
- National Highways has allocated £15m to improvements on the A38 corridor between Exeter and Plymouth.
- Whitecleave and Mardle viaduct works include full bridge-joint replacement and drainage improvements under restrictions extending into January 2027.
- Further schemes cover gantry safety, drainage between Lee Mill and Ivybridge, and other corridor asset-management work.
National Highways is preparing a £15m programme of renewal and safety work along the A38 between Exeter and Plymouth, with major bridge-joint and drainage works due to begin at Buckfastleigh in September.
The programme includes Whitecleave and Mardle viaducts, where previous short-term repairs will be replaced with a longer-term intervention. Traffic management is scheduled to begin on 2 September 2026 and remain in place until 25 January 2027.
The viaduct package covers full replacement of the bridge joints together with drainage improvements. National Highways intends the work to reduce the risk of unplanned closures after using local repairs to keep the structures safe and operational while the permanent scheme was developed.
Bridge joints form a relatively small visible part of a highway structure but have a demanding role. They must accommodate movement caused by temperature, traffic loading, creep, and other structural effects while maintaining a durable running surface and controlling the path of water across the deck.
When joints deteriorate, water and road contaminants can reach bearings, deck edges, abutments, and other structural components. Replacing the joint without correcting drainage defects can therefore leave the conditions that accelerated deterioration in the first place.
The Buckfastleigh programme combines both activities, but the work has to be carried out while maintaining capacity on one of the principal road links into Devon and Cornwall. One narrow lane will remain open in each direction through much of the works, supported by a 40mph speed limit and average-speed enforcement.
Selected overnight closures are also planned between Dart Bridge and Marley Head. These provide larger possession windows for operations that cannot safely be completed beside live traffic but place additional pressure on the construction team to establish traffic management, complete the planned activity, clear the work area, and reopen the route to programme.
The location limits the usefulness of extended diversion routes. The A38 carries substantial local and tourist traffic and is one of two key strategic routes linking Devon and Cornwall with the wider South West, making prolonged loss of capacity commercially and operationally difficult.
National Highways is therefore using a mixture of lane closures, full closures, temporary signals, contraflow, and other measures across the corridor rather than applying one traffic-management model to every package.
The wider £15m investment extends beyond the two viaducts. Safety improvements between Wobbly Wheel and Splatford will enhance signage on four gantries at a location prioritised because of its collision history and the severity of recorded injuries.
That work is due to run overnight between 1 September and 12 October, using a combination of closures and reduced-speed traffic through short sections. The package illustrates how road renewal increasingly combines structural maintenance with targeted operational changes intended to address accident patterns.
Another substantial programme is planned between Lee Mill and Ivybridge, where drainage improvements are scheduled from November 2026 until October 2027. National Highways intends to maintain capacity through a contraflow for most of that work.
Long-duration drainage schemes are disruptive but can prevent more expensive deterioration elsewhere in the asset. Poor drainage accelerates pavement failure, undermines earthworks, increases standing water, and can expose structural components to repeated saturation.
The delivery challenge across the A38 will therefore be less about any single engineering technique than about coordinating several interventions without creating overlapping restrictions that materially reduce route capacity.
Asset-management programmes also produce a different supply-chain profile from major new road construction. Individual packages may be smaller, but they require repeated use of traffic management, bridge repair, drainage, surfacing, road restraint, signage, electrical work, surveying, and specialist inspection services.
Much of the engineering has to fit around the existing asset rather than replace it. Conditions become clearer only after traffic management is installed and existing joints, drainage runs, buried services, or structural details are opened up, leaving less tolerance for assumptions based solely on records.
Weather adds another variable, particularly for surfacing, waterproofing, concrete repair, and other activities sensitive to temperature or rainfall. National Highways has already warned that published dates may move where weather or operational conditions prevent work proceeding as planned.
The September start will therefore begin a sequence extending well into 2027 rather than a single roadworks package. Whitecleave and Mardle provide the immediate focus, but the £15m investment is effectively a corridor-wide attempt to deal with deterioration and safety issues before they become larger and more disruptive failures.
For an ageing strategic road network, that maintenance is rarely as visible as opening a new route. The economic effect of not doing it tends to become considerably more visible when a failed joint, drainage system, or structure closes one.
