According to National Highways, the restriction follows inspections that revealed deterioration in the cables, which have weakened over time. The measure is intended to preserve the structural integrity of the bridge and allow most traffic to continue using the route while works are carried out.
Chris Pope, Programme Delivery Manager at National Highways, said:
“Safety is our number one priority, and this weight restriction is about future-proofing the bridge 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.”
The M48 Severn Bridge, which opened nearly six decades ago, carries approximately 32,000 vehicles daily, of which around 10% (3,270 vehicles) are HGVs over 7.5 tonnes. These vehicles will be diverted to the M4 Prince of Wales Bridge, a route that adds approximately 14 miles to the journey.
Planned and unplanned diversions
The restriction applies to most HGVs over 7.5 tonnes, but exemptions have been made for emergency vehicles, coaches, scheduled buses, gritters and recovery vehicles.
During planned overnight closures of the M4 Prince of Wales Bridge, affected HGVs will temporarily be allowed to use the M48 bridge. However, in the event of an unplanned closure of the M4 route, HGVs will need to follow a significantly longer diversion via the M5 and M50, extending the detour to approximately 100 miles.
National Highways is currently exploring the use of Automatic Number Plate Recognition (ANPR) cameras to support enforcement of the new restriction.
The restriction will remain in place while National Highways develops and installs a medium-term solution to manage in real time the number of heavier vehicles using the M48. This may include traffic management tools such as signage, barriers, or signals to ensure safety limits are maintained.
In response to queries regarding compensation, National Highways confirmed that no compensation is available to operators for the disruption. A spokesperson explained:
“We’re not obliged or required to pay compensation for disruption, costs, or inconvenience, caused by roadworks. This is because the work we do (maintaining and improving the highways for all to use) is considered a statutory duty on behalf of the Secretary of State for Transport. This is covered under section 278 of the Highways Act 1980.”
“Safety first” – but at a cost to hauliers
The Road Haulage Association (RHA) has expressed concern over the impact of the restrictions on logistics operators but welcomed the communication and planning efforts being made.
“The RHA will remain in close dialogue with National Highways and other stakeholders ahead of, and during this period – and will provide updates as they emerge,” the organisation stated in a bulletin to members.
The weight restriction comes at a time when the UK’s road freight sector continues to face infrastructure challenges, with many bridges and roads built decades ago now having to accommodate significantly heavier and more frequent HGV traffic. Since the removal of tolls on the Severn bridges in 2018, traffic on the M48 has increased by 34%, further intensifying the load on ageing infrastructure.
