M4 near Langley and Slough to close for further smart motorway work
Part of the M4 will close over the weekend as part of ongoing work to turn it into a so-called smart motorway.
Both carriageways will close between junction five at Langley and six for Slough, from 20:00 BST on Friday until 06:00 on Monday.
Highways England said the Smart Motorway project would "increase capacity and reduce congestion".
The westbound exit slip road at junction five is also set to close overnight on Wednesday and Thursday.
Between junctions three and 12 the hard shoulder is being converted to a traffic lane to make four lanes available for use by vehicles.
Technology is being installed to monitor traffic flow and set speed limits and 11 bridges are being replaced.
Critics of smart motorways have previously raised fears about their safety after fatal accidents involving stationary cars being hit from behind.
In April the government announced that no more smart motorways without hard shoulders would be able to open without additional safety measures in place.
The M4 project started in 2018 and is due to be completed in spring 2022 at an estimated cost of £848m.
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