People travelling in and out of Wales are advised to take note of a major road closure
11:43, 22 Oct 2025
This article contains affiliate links, we will receive a commission on any sales we generate from it. Learn moreAn impression of the new A432 Badminton Road bridge (Image: National Highways)
Drivers have been warned to expect significant disruption to one of Wales’ busiest routes this weekend, as a major section of the M4 will be completely closed to traffic. Construction works for a new bridge will take place on the M4 from Friday night.
National Highways has said the M4 motorway north of Bristol will be closed in both directions between Junction 18 (Bath) and Junction 19 (M32) from 7pm on Friday, October 24 until 6am on Monday, October 27.
The closure is to allow eight large steel beams to be lifted into place for the new A432 Badminton Road Bridge, marking a major milestone in the ongoing infrastructure project. The beams will be installed in groups of two over the course of the weekend, using specialist machinery.
Route manager for National Highways, Sean Walsh, said: “The beam lift is a huge milestone in the construction of the new bridge, but we appreciate that any road closures can be frustrating for people.
“We need to fully close the M4 because we’re using specialist machinery and it’s vital that we keep those doing the work and motorists safe.
“Once complete, the new bridge will help reconnect drivers, businesses and the local communities that have been impacted by the closure.” For the biggest stories in Wales first, sign up to our daily newsletter here
The M4 is one of the busiest roads in Wales and the West of England, with up to 4,000 vehicles using this stretch every hour during peak weekend periods.
As such, the closure is expected to cause substantial delays, with drivers strongly advised to avoid the area where possible, plan alternative routes, or travel at off-peak times.
The new bridge, which is 46.5 metres long and 20 metres wide, will span all eight lanes of the M4. It is being constructed slightly wider than the old bridge to meet modern safety standards, including wider pavements and higher protective barriers for pedestrians and cyclists.
The bridge will be closed to all users for the weekend from Friday 24th October, with a diversion route in place.(Image: National Highways)
Once this weekend’s beam installation is complete, the remainder of the bridge works are expected to cause minimal disruption to the motorway. The bridge is due to open to the public in early 2026.
A signed diversion will be in place throughout the closure period. Westbound traffic will be directed to exit the M4 at Junction 18 and join the A46 towards Bath.
At the A46/A420 junction just past Pennsylvania, drivers should take the A420 towards Warmley, then follow the A4174 towards the M32 at the A420/A4174 junction. From there, vehicles will join the M32 at Junction 1 and continue to M4 Junction 19. Eastbound traffic will follow the same route in reverse.
In light of the closure, National Express confirmed that their services will still be operating, however certain stops including in Cardiff and Chepstow will be suspended until Monday.
The full statement from the company, reads: “National Express will continue to operate services along diverted routes during this weekend’s closure of the M4 between junctions 18 and 19.
“The following stops will be suspended until 06:00 on Monday, 27 October: Cardiff (Gabalfa), Cardiff University, Cardiff Gate Business Park, University of West England, Bridgwater (504 service only), Chepstow, and Reading Mereoak P&R (504 and 508 service only). Live service updates are available here.
“Delays are expected and customers are advised to allow plenty of time for their journey, particularly if travelling to an airport. Customers who are affected by this diversion have been contacted to offer a free amendment to their ticket should they wish to change their travel plans.”
National Highways thanked road users for their patience and says the works will help improve long-term safety and reliability for all who use the route.
