Thousands of drivers are expected to face disruption this weekend when the M4 closes in both directions between junctions 10 and 11.
The motorway will shut from 21:00 BST on Friday, 18 September until 06:00 on Monday, 21 September, between junction 10 at Winnersh and junction 11 at Reading.
The closure is needed to allow Scottish and Southern Electricity Networks (SSEN) to carry out essential work to restore a key part of the overhead electricity network.
A replacement electricity tower was installed in Winnersh in July following damage earlier this year, with the weekend closure allowing new high-voltage wires to be installed across the motorway.
National Highways said through traffic would be diverted via the A329(M) and B3270, and urged motorists to plan ahead, allow extra time and follow the signed diversion rather than relying on sat-nav directions.
The closure coincides with Reading FC’s home fixture against Notts County on Saturday.
The Royals have urged supporters attending the match at the Select Car Leasing Stadium to arrive early because of the expected disruption.
The club has been working with SSEN, National Highways and other organisations ahead of the closure and has advised supporters to plan their journeys and allow additional time.
The closure is also expected to affect other people travelling around Reading and Wokingham during the weekend, with traffic diverted away from the motorway.
National Express has warned that a number of its services are likely to experience delays because of the closure.
A spokesperson said: “National Express will continue to operate services along diverted routes during this weekend’s closure of the M4 between junctions 10 and 11.
“While we endeavour to minimise disruption, there are likely to be delays to a number of our services.
“The impacted services are: 040, 200, 201, 202, 401, 403, 404, 406, 444, 501, 502, 504, 507, 508, 509.
“The stops at Reading-Mereoak, the University of the West of England and Cardiff Gate will be suspended from 20:00 on Friday, 18 September until 06:00 on Monday, 21 September.
“Customers are advised to allow plenty of time for their journey, particularly if travelling to an airport.
“All affected customers will be contacted to offer a free amendment to their ticket should they wish to change their travel plans.”
National Express said live service updates would be available through its website.
Drivers have been advised to check travel conditions before setting off and allow additional time for journeys during the closure.
The M4 is expected to reopen at 06:00 on Monday, 21 September.
