National Highways has announced a preferred medium-term solution to lift the heavy goods vehicle (HGV) weight restriction on the M48 Severn Bridge, which has been in place since May due to safety concerns over deteriorating suspension cables.
The new system aims to allow lorries over 7.5 tonnes to return to the historic crossing by next autumn while ensuring the safety and structural integrity of the bridge.
Background
The M48 Severn Bridge, which connects England and Wales, has been subject to a 7.5-tonne weight limit since spring 2025 after inspections revealed significant corrosion and strength reduction in its main suspension cables.
Since its opening nearly 60 years ago, the bridge has faced the challenge of supporting increasingly heavier vehicles and higher traffic volumes. HGV weights have doubled from around 22 tonnes to 44 tonnes, while overall traffic increased by 34% following the removal of tolls in 2018.
In 2024, the bridge carried approximately 32,000 vehicles a day, with more than 3,200 of those being HGVs. Those vehicles have since been diverted to the newer M4 Prince of Wales Bridge, increasing journey times for hauliers and businesses.
The Proposed Solution
Under the proposed plan, HGVs will be required to exit the M48 at Junction 1 (westbound) and Junction 2 (eastbound) before re-joining via controlled slip roads. Traffic lights will manage their return to the motorway, allowing National Highways to safely space out heavy vehicles across the bridge.
The system will typically operate “freely”, meaning that HGVs will rarely experience delays. However, it can also be activated to restrict access in emergencies or during maintenance operations.
Alan Feist, Programme Leader for National Highways, said:
“Safety is our number one priority, and this weight restriction is about keeping the bridge safe for use now and for years to come.
“Whilst the bridge remains safe, it was not designed and built for today’s levels or weight of traffic. Vehicles have got heavier, and traffic levels have increased significantly over the last 60 years, putting greater load on the cables.”
We appreciate that this has been disruptive for businesses and hauliers, but we have been working at pace to reach this solution and are pleased to be on track to get HGVs back onto the M48 Severn Bridge next year.”
Government and Welsh Support
The UK Roads and Buses Minister Simon Lightwood welcomed the progress, stating:
“I am pleased to see National Highways making progress to allow HGVs to return to the M48 Severn Bridge next year. Safety remains the number one priority, while ensuring this important crossing continues to serve the businesses and communities who depend on it.”
The Welsh Government also expressed support. Ken Skates, Cabinet Secretary for Transport and North Wales, said:
“We welcome and support the news from National Highways. We will continue to engage with the team as measures to address a longer-term solution for the Severn Bridge weight limit are explored.”
The Ongoing Challenge
The 2022–2024 inspections of the Severn Bridge revealed the main suspension cables had deteriorated due to decades of exposure to wind, rain, and sea air. Laboratory testing confirmed corrosion and reduced cable strength, prompting the temporary restrictions to reduce further stress on the structure.
National Highways emphasised that continued use by vehicles exceeding the weight limit could force a complete closure of the bridge. For now, emergency vehicles, buses, coaches, gritters, and recovery vehicles remain exempt from the restriction.
If the Prince of Wales Bridge is closed unexpectedly, HGVs must use the official diversion route via the M5 and M50.
What Happens Next
The new HGV control system is expected to be operational by autumn 2026, restoring the bridge’s vital role for freight transport while longer-term strengthening or replacement options are considered.
Mr Feist added:
“We’d like to thank drivers for their support and must stress that only vehicles up to 7.5 tonnes in weight should use the bridge. Continued use by heavier vehicles could ultimately see it closed to all traffic. We are acting now to prevent this from happening.”
Photo captions:
• The preferred option for the M48 westbound
• The preferred option for the M48 eastbound