Construction of the largest single stretch of Smart Motorway is on track to start in March 2017 following award of a Development Consent Order for the M4 Junction 3 to Junction 12 project west of London.

Award of the DCO for the M4 J3-12 scheme is the 11th successful application for 'nationally significant' highway schemes through the 2008 Planning Act, which was designed to speed up statutory planning procedures for major projects.

The M4 Smart Motorway project will upgrade 32 miles of the M4 between Hayes and Theale.  The £860m project will add capacity to the M4 by converting the hard shoulder to a permanent running lane with concrete central reserve barriers throughout, emergency refuge areas, overhead gantry signs and the reconstruction of 11 new overbridges to make room for the carriageway widening.

Highways England awarded two contracts in July 2015 to take development of the M4 J3-12 project forward, as part of a £1.5 billion investment to build 10 Smart Motorways. A CH2M and Arcadis joint venture was appointed to develop the detailed design for the scheme. A Balfour Beatty and VINCI joint venture was awarded a contract to support the design work with construction methodology and programme advice, and to ensure the design delivers efficiencies and minimises disruption to customers during construction.

The M4 project is the largest of three Smart Motorway schemes that will be developed and ultimately delivered by CH2M/Arcadis and Balfour Beatty/VINCI. This team is already building Smart Motorway on the M5 from J4a-6 in Worcestershire. It is also working on development of the M6 J2-4 project.