M48 Severn Bridge weight restriction from 27 May – information for operators
14 Apr 2025
Posted By Paul Mummery
The M48 Severn Bridge will have a 7.5t weight restriction for most HGVs from 27 May for 12-18 months.
The main bridge cables have deteriorated and weakened. The load on these cables needs to be reduced to keep the bridge open for most traffic.
National Highways will carry out works to resolve the issue during this period.
Diversions for affected vehicles will be in operation – via the M4 Prince of Wales Bridge in the first instance.
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.
Here's some useful information to help affected operators:
What is the weight restriction on the M48 Severn Bridge and who will it apply to?
It applies to most HGVs of 7.5t or over from 27 May for 12-18 months.
It does not affect coaches, gritters and recovery vehicles.
What route should affected operators use?
Affected HGVs over 7.5t will need to use the M4 Prince of Wales Bridge to cross the Severn Estuary.
This is a diversion of 14 miles.
What will happen when there’s a planned closure of the M4 Prince of Wales bridge?
HGVs of 7.5t or more will be able to use the M48 bridge during planned overnight closures of the M4 bridge.
What happens in the event of unplanned closures?
If there is an unplanned closure of the M4 Prince of Wales bridge, HGVs over 7.5t will need to follow the official diversion route via the M5 and the M50.
This is a diversion route of approximately 100 miles.
How long will the weight restriction on the M48 bridge last?
It’s in place for an estimated 12-18 months. This depends on their further investigations while they develop medium-term solutions to help them manage the number of vehicles over 7.5t using the bridge over the longer term.
The medium-term solution aims to lift the 7.5t restriction by combining technology and traffic management tools (like signs, barriers or signals).
Is National Highways obliged to offer compensation for disruption?
No. National Highways explains:
“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.
What is the RHA doing?
We are in regular dialogue with National Highways about this work and will feed back industry views through these channels.
Likewise, we will continue to update our members and the wider industry on this programme when new information is available.
Where can I get further information?
We will issue updates through our channels and networks in the lead up to – and during – the weight restriction being in place.
National Highways explains more about why they’re implementing the weight restriction and the work they’re doing to strengthen the bridge: .
You can also contact National Highways with any queries here: