The M4 motorway is a vital artery linking London with South Wales, passing through key areas, including Bristol. Recently, motorists and local residents have experienced significant disruptions due to planned and necessary closures on this stretch, particularly between junctions 18 (Bath) and 19 (M32, Bristol). This article explores the reasons behind these closures, the impact on travel, key developments, and how to navigate this busy route during ongoing works.
Why Are the M4 Closures Happening in Bristol?
The primary cause of the current closures is a major infrastructure upgrade linked to the A432 Badminton Road Bridge, which crosses the M4 on the outskirts of Bristol. Engineers identified critical structural cracks in this bridge, originally built in 1966. The decision was made to demolish the old bridge in early 2025 and build a brand-new one to meet modern safety and capacity standards.
To facilitate this major project, National Highways implemented a series of closures on the M4, especially around junctions 18 and 19. The closures have allowed for the removal of the old bridge, ground investigations, utility removals, and installation of large steel beams required for the new structure. These works are due to continue until early 2026 when the new bridge is expected to open to traffic.
Recent Closure Details and Timings
One of the most significant recent closures was a full motorway shutdown from 7 pm on Friday, 24 October 2025, until 6 am on Monday, 27 October 2025. Both directions of the M4 between junctions 18 and 19 were closed to install eight massive steel beams atop the new A432 bridge. This work created widespread traffic delays, with congestion reported back to junction 17 for Chippenham and affecting thousands of vehicles.
National Highways estimated that between 3,000 and 4,000 vehicles use this stretch hourly during peak weekend periods. Consequently, the closure caused substantial disruption, prompting advice for drivers to avoid the area where possible or plan alternative routes.
Besides this weekend shutdown, ongoing night closures affected the eastbound lanes between junctions 15 and 16, running from mid-October through early November for resurfacing and maintenance work along the M4 corridor.
Traffic Impact and Local Disruptions
The M4 closures have not just affected motorway users but also had ripple effects on local roads and communities. Alternative routes, including the A46, A420, A417, and M32, experience increased traffic volumes as drivers seek ways around the affected motorway sections.
This surge has led to extended journey times and significant congestion, especially during peak hours. Local residents in nearby areas, including villages on diversion routes, have described the situation as “absolute carnage,” with delays impacting daily commutes and business access.
Emergency services and police have been involved during some closures due to incidents such as motorists attempting unsafe manoeuvres or trying to evade traffic restrictions.
What National Highways Says
National Highways has released multiple statements providing updates and guidance. They emphasise the importance of these closures for the safety and long-term improvement of the M4 infrastructure and recommend that drivers check for updates regularly.
The authority confirmed that this closure is the last full motorway shutdown expected for the bridge project. Once the new A432 Badminton Road Bridge opens, traffic flow should improve significantly, easing pressure on junctions 18 and 19.
What Can Drivers Do?
Motorists planning to use the M4 around Bristol should consider the following advice:
- Stay updated with National Highways traffic alerts before travelling.
- Avoid travelling during planned closures where possible.
- Plan alternative routes in advance, using the A46, A420, M32, or other local roads when the motorway is closed.
- Allocate extra journey time during periods of known works.
- Use real-time traffic apps or listen to traffic information on local radio stations.
Broader Context: Infrastructure Upgrades Across the UK
The M4 closures are part of a wider national effort to upgrade ageing road infrastructure to meet 21st-century traffic demands. Many UK motorways are undergoing resurfacing, bridge replacement, and smart technology integration aimed at improving safety, reducing congestion, and supporting economic growth.
Specifically, the new Badminton Road Bridge will better accommodate increased traffic volumes and enhance connectivity between Bristol, Bath, and surrounding areas.
Looking Ahead: Completion and Aftermath
Construction work on the new bridge and associated motorway sections is scheduled for completion in early 2026. Once finished, motorists will benefit from a safer, more resilient crossing over the M4 that supports growing regional transport needs.
Local councils and agencies are also expected to monitor traffic patterns post-work to mitigate any lingering issues from diversions and increased road usage during the construction phase.
FAQ on M4 Closures in Bristol
1. Why is the M4 near Bristol closed recently?
The M4 near Bristol was closed mainly to replace the ageing A432 Badminton Road Bridge due to structural damage and safety concerns.
2. How long will the M4 closures last?
Major closures, including a full weekend shut down, took place in October 2025. Construction and maintenance works continue until early 2026.
3. What are the best alternative routes during closures?
Drivers should use diversion routes such as the A46, A420, A417, and the M32 to navigate around closed sections.
4. How has the closure affected traffic?
The closures have caused severe traffic congestion and longer journey times both on the motorway and local roads due to diverted traffic.
5. Where can I find live updates about the M4 closures?
Live updates are available from National Highways, local traffic news services, and UK transport authorities online and via radio.
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