Between junction 3 of the M4, just inside the M25 near Heathrow Airport, and junction 12 at Theale, west of Reading, will now see the hard shoulder converted into an additional lane of traffic and technology introduced to impose electronically-policed variable speed restrictions. Loops under the road surface will monitor traffic flows.
As part of the works, 11 overbridges will be replaced with larger span structures and six underbridges will be widened to accommodate four lanes. Contractor for the project is Balfour Beatty Vinci JV. Highways England puts the project costs at between £586.4m and £862.4m.
The scheme was originally designed by an alliance of URS, Halcrow Hyder JV and Mouchel. As part of a £1.5bn investment to build 10 smart motorways, Highways England awarded two contracts in July 2015 to take the development of the M4 junctions 3 to 12 scheme forward. A joint venture of CH2M and Arcadis was appointed to develop the detailed design for the scheme. A joint venture of Balfour Beatty and Vinci was appointed to work alongside the designers to develop the construction programme under early contractor involvement (ECI). [See previous report here.]
Completion date is set for end of March 2022.
The M4 junctions 3 to 12 smart motorway scheme is classed as a nationally significant infrastructure project (NSIP). Third party land is required, on both a temporary and permanent basis, to enable the scheme to be constructed and, as such, Highways England was required to submit a development consent order (DCO) application to the Planning Inspectorate in order to gain consent to undertake the scheme.
The application was submitted to the Planning Inspectorate for consideration on 30th March 2015 and accepted for examination on 27th April 2015. Following a six-month examination, a recommendation was made to the secretary of state for transport on 3rd June 2016. Transport secretary Chris Grayling has now given his seal of approval, completing the pre-construction regulatory process.