M4, M5 and M6 Smart Motorways

The M4, M5 and M6 contracts are part of the Highways England Smart Motorway Programme (SMP), which involves converting sections of the M5 between junctions 4a and 6 (covering more than 18km), the M4 between junctions 3 and 12 (51km) and the M6 between junctions 2 and 4 (22km) into smart motorway by using the hard shoulder. Highways England, the authority responsible for England’s motorways, awarded the contracts to a joint venture comprising VINCI Construction Grands Projets, VINCI Construction UK and Balfour Beatty.


The M5 motorway, the first contract covered by the Smart Motorway Programme, is a key route for traffic in south-west England. The project involves upgrading the M5 from a 3-lane to a 4-lane motorway between junctions 4a and 6, to the south-west of Birmingham.
The M6 project consists of improving the busy 22km stretch between junction 2 at Coventry and junction 4 near Coleshill, to the east of Birmingham.
The M4 project covers the stretch between junctions 3 at Hayes and 12 at Theale of the main strategic route between London, the West of England and Wales.
The purpose of the Smart Motorway Programme is to smooth traffic flow by increasing the capacity of existing motorways, without widening them. This is achieved by making the hard shoulder available for use and introducing variable speed limits.

Technical overview

The carriageways are extended from three to four lanes by converting the hard shoulder into a traffic lane and using an all-lane running system.
The smart motorway projects also involve the installation of a new vehicle restraint system to protect gantries, signs and structures; removal of existing gantries and installation of new ones; construction of refuge areas at 2.5km-intervals including retaining walls and embankments; upgrade of the drainage system; asphalt repaving of the dual 4-lane carriageways, and installation of traffic management equipment. The M4 project also requires the demolition then reconstruction of 11 bridges.
Furthermore, the project involves installing radars that analyse traffic flow in real time. These feed traffic information to a control centre, which can then regulate speed limits using a digital signage system in order to keep hold-ups to a minimum. The system implemented is a communication tool that enables multimedia content to be delivered remotely and in real time across a network of digital signs.
The project also includes real-time management of traffic flow based on traffic volumes. Here again, sensors send data to a control centre that regulates speed limits using a digital signage system.

This project marks the introduction of new so-called smart motorways, where the use of technology plays a central part.


Thanks to smart traffic management and motorway use, thousands of drivers will enjoy smoother traffic flows on a daily basis.
Following on from the widening of the M1 motorway from junction 25 to 28, carried out in the UK between 2007 and 2010, the East End Crossing motorway stretch in Indiana in the US, currently under way, and the New Coastal Road on Reunion Island, also under way, this project enables VINCI Construction Grands Projets to develop its recognised expertise in complex road works.

M1 Widening Junctions 25 to 28