The M4 is the main strategic route between London, the west of England and Wales. It connects people, communities and businesses, carrying on average 130,000 vehicles per day and is prone to congestion.

Highways England will be improving the M4 between junction 3 at Hayes and junction 12 at Theale by upgrading it to a smart motorway.

This means there will be:

  • An additional lane for traffic increasing capacity to reduce congestion.
  • More technology on the road to smooth flows and manage incidents.
  • More reliable journeys.

The M4 junctions 3 to 12 project has received planning permission through the Development Consent Order (DCO) process. Following a statutory consultation, it was granted consent in September 2016. Since then we have been working on detailed design and planning construction. Work on the motorway will start in summer 2018 and is expected to be completed in spring 2022.


As part of the preparatory works for the start of main construction in the Autumn, there will be some overnight closures of the M4 motorway between junctions 8/9 and 10 in the next week. These will take place as follows:

  • Saturday night 18th August 2018 from 22:00 to 05:00 – Eastbound carriageway
  • Sunday night 19th August 2018 from 22:00 to 05:00 – Eastbound and Westbound  carriageway
  • Monday night 20th August 2018 from 22:00 to 05:00 – Westbound carriageway


Information on closures can be found on the project website at:

Vegetation clearance has also begun in several areas and we are currently notifying residents who may be impacted by this. Much of the work required for the project will be carried out at night in order to minimise disruption to motorway traffic. Construction is being carried out under the Development Consent Order granted by the Secretary of State for Transport in September 2016 and with local consent under Section 61 of the Control of Pollution Act 1974, with notifications going to residents living near areas where potentially noisy works are planned.



Read more here: M4 J3-12 smart motorway leaflet