A signal system to ensure there are never too many lorries on the M48 Severn crossing is one proposal for getting heavy vehicles back using the bridge by Autumn 2026.
National Highways said it would engage with hauliers on its plans, which would allow the current 7.5-tonne weight restriction to be removed.
Following safety inspections this year that found deterioration to supporting cables, HGVs travelling between England and Wales have been diverted via the Prince of Wales bridge, with the M48 bridge remaining open to all other traffic.
National Highways said it was looking at two options at both Junctions 1 and 2 of the M48, to manage loads which would allow HGVs back across the bridge without overloading the cables.
Alan Feist, programme leader for National Highways, said: “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 on these options and are pleased to be on track to get HGVs back onto the M48 bridge next year.”
A solution is to route westbound lorries off the M48 via the off-slip and on-slip and control re-entry by way of signals.
One option would control access for all vehicles whilst another would have a dedicated HGV lane, controlling access back onto the bridge.
A second proposal at junction two involves either controlling HGV movements using traffic signals across the roundabout or, as at Junction 1, controlling lorry access from the eastbound on-slip using signals.
National Highways said that for the vast majority of the time, the system would operate ‘freely’ to release HGVs so they are spread out across the length of the bridge and not concentrated in close proximity, creating very little delay to HGV or car traffic.
The system could also be used to keep lorries off the bridge if there is a significant incident in the area.
It is now engaging with South Wales Trunk Road Agency, local highways authorities and several businesses and hauliers in the area, ahead of implementation by October next year.
The M48 Severn Bridge carried around 32,000 vehicles a day in 2024, 3,270 of which were over 7.5-tonnes, meaning around 10% of traffic is currently diverted via the M4 Prince of Wales bridge.
