The Highways Agency has applied to the planning inspectorate for a development consent order (DCO) for the project, which would make the M4 motorway between junctions 3 and 12 a 'smart motorway’.
The project, which was first proposed in 2010, will help to ease congestion by using technology to vary speed limits and by opening up the hard shoulder as a running lane at peak times to create additional capacity.
The DCO will speed up the planning process, by holding consultations prior to the application being submitted, so that the determination period is reduced.
A Highways Agency spokesman said: “The Highways Agency is working on proposals to provide much needed capacity on the M4 between junctions 3 and 12 to support the economy. A Development Consent Order is being applied for as part of the planning mechanism required.”
Preliminary consultations on the project are scheduled to take place this month and in April, before a draft application is submitted in July and further consultations held in September. The final application is scheduled to be submitted in late 2014 or early 2015.
Cllr Richard Kellaway, chairman of the Royal Borough’s highways, transport and environment overview and scrutiny panel, said: “I guess it would make it a lot better for the Royal Borough, but I suppose if it increases capacity, then it can draw more cars to it.
“Maidenhead is developing fast at the moment so the population is going to go up, and the Royal Borough’s population has gone up by 10-11,000 in the last 10 years so there will be more demand for it.”
The Highways Agency says the project will deliver these benefits at a lower cost than conventional motorway widening. It is likely to cost between £614m and £862m.
It also claims there will be less impact on the environment during construction, with low impacts on watercourses, habitats and the landscape, but there are risks of an impact on the air quality, noise and a visual impact.
The project qualifies as a nationally significant infrastructure project as it is an alteration to the highway, the scheme is wholly in England, the Secretary of State is the highway authority, and the area of development is greater than 15 hectares.
The project will apply to a 32 mile stretch of the motorway, between the A312 at Heathrow Airport to Theale in Berkshire, which on average 130,000 vehicles use per day.
The scheme aims to ease congestion and smooth the flow of traffic, improve journey times, maintain safety levels and support economic development in the region.