Drivers are being warned to expect disruption and allow extra time for their journeys ahead of a full weekend closure of the M4.
The motorway will be closed in both directions between junction 18 for Bath and junction 19 for Bristol from 7pm on Friday 21 March until 6am on Monday 24 March, to allow the A432 Badminton Bridge to be demolished.
National Highways said the bridge, which was built nearly 60 years ago, needs to be replaced after cracks appeared in the structure.
A spokesperson for the organisation said: “This is one of the southwest’s busiest sections of motorway. We expect the closure will cause substantial disruption.
“If possible, please avoid driving on the M4 round Bristol during the closure. If you have to travel, allow plenty of extra time for your journey using signed diversion routes.”
The official diversion takes drivers south of the M4 through Emerson’s Green, Warmley and Wick.
Drivers travelling west will be asked to follow these diversions:
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from M4 junction 18, exit the motorway roundabout to the A46 heading towards Bath
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at the A46/A420 junction just past Pennsylvania take the A420 towards Warmley
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at the A420/A4174 junction in Warmley, take the A4174 towards the M32
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join the M32 at junction 1 and head to the M4 junction 19
If you’re travelling eastbound, follow these directions in reverse.
National Highways said construction of the new bridge will begin later this year, with the project scheduled for completion in spring 2026.
