Speculation has surfaced that a congested section of the M25 could be relieved by building a double deck carriageway. The idea is one of many said to be under consideration as part of an ongoing study to improve performance of the motorway between junctions 10 and 16 near Heathrow.

 

It is understood that the idea of double decking the M25 came from a brain storming session hosted by the Department for Transport (DfT). Its consideration of the measure could be a sign that all cost effective solutions for providing extra capacity to the western side of the M25 have been exhausted.

 

In a statement the DfT said: “As part of our long term work into how we can improve the M25 between junctions 10 and 16 stakeholders have been asked to put forward initial options for future consideration. This work is at a very early stage and no decisions have been made.”

 

The DfT announced in March a study to boost transport infrastructure in the South East but the double deck M25 idea only came to light in The Times newspaper on Saturday.

 

RAC Foundation director Steve Gooding said: “The fact is we face huge capacity problems on several sections of our motorway network, which are already some of the busiest in Europe and are predicted to become busier still. But where they already have five lanes in each direction we're going to need some clever, lateral thinking to come up with workable solutions.”

 

But he added: “Ultimately we are left trying to fit a quart into a pint pot, which might mean we need to adjust our expectations about how fast some sections will flow.”

 

Accountancy firm EY’s director of smart cities and transport Nathan Marsh described the double deck motorway as "an interesting concept" but said it would need the right mix of funding and finance to be in place.

 

“Population in the South East continues to grow and there may be consequences if extra highway capacity is not provided, or travel patters are not dramatically changed. But infrastructure schemes of this kind should not be viewed in isolation and should consider the impact of, for example, building a new airport runway in the South East,” he said.

 

One prominent highways specialist on the contracting side welcomed the double deck proposal. “We should very much keep our minds open to alternatives and not be constrained by what we have always done,” he said. “We must not lose our sense of adventure and innovation, although we must also ensure that any elevated sections are well designed to reduce the need for maintenance.”

 

Campaign for Better Transport representative Bridget Fox said: “Some of the new road options being floated are so damaging to precious landscapes and local communities that it is simply unacceptable they should progress at this stage. We want Highways England to remove them from any further consideration.”