Drivers heading into Cornwall on the A30 are being asked to ignore their satnavs and remain on the main road. This follows the introduction of new signs after a safety scheme caused satnav devices to reroute traffic onto narrow rural lanes.
Signs guiding drivers on the A30
National Highways has placed signs instructing drivers to use both lanes approaching junctions and to merge in turn. Additional signs inform that Plusha Services remains open and urge drivers to stay on the A30 rather than diverting onto local roads.
“Local Access Only” signage is being added at key points on side roads to discourage through traffic. A variable message sign at Exeter informs drivers of congestion on the A30, enabling them to choose alternative routes early, while still on the M5.
How the safety scheme affects traffic
The £9.8 million A30 Kennards House to Five Lanes safety improvements cover six junctions: Plusha, Trevell, Polyphant, Two Bridges, Blackhill Quarry and the Highways depot. The scheme addresses a high incidence of collisions, particularly at junctions, without increasing road capacity.
The work, which began in September and is due to complete by spring 2027, has led to queues on the A30. Satnavs have responded by directing vehicles through nearby villages, prompting complaints from residents, councillors and MPs.
Adjusting the response to satnav rerouting
National Highways, aware of these issues, is working with digital services and satnav providers to change route data. These changes require careful testing before being implemented. Until then, satnavs will continue to recommend the fastest route based on existing data, even if it leads down single-track lanes.
Meanwhile, a single-lane access allows agricultural vehicles to reach Plusha Services safely, and the programme timetable is adjusted to maintain access at Two Bridges.
Why merging in turn matters
Merging in turn means drivers use both lanes up to the point where one ends, then alternate which vehicle proceeds next. This method utilises the full road width, shortens queues, and reduces the incentive for satnavs to find alternative routes.
Local feedback and ongoing monitoring
National Highways has described the signage changes as minor adjustments following consultation with local communities, a standard practice on road schemes. Ian Ellis, programme manager, said the organisation recognises the need to maintain reliable journeys while minimising local disruption.
“We have listened to feedback and introduced a number of traffic management measures on the A30 and nearby local roads. We continue to monitor traffic conditions and will assess mitigation measures to keep disruption to a minimum,” he said.
A clear message for westbound drivers
The problem of satnav rerouting on this stretch is not new. Complaints were raised recently when satnavs directed A30 traffic through a primary school area. For now, the clear instruction from National Highways is to stay on the A30, even if satnav devices suggest otherwise.
