Road chiefs are looking to ease congestion by creating more mini-motorways across the UK.
Busy A-roads will be revamped to form new 70mph “expressways”, with roundabouts and traffic lights stripped out to ease traffic and cut delays.
The proposals by Highways England include new slip roads, extending ones that are currently too short, and banning slow-moving vehicles, including tractors, from using them. Some roads will be widened to up to three lanes.
In the same report, Highways England also warns that traffic is set to rise by more than a third in the next two decades, with average speeds on the network predicted to fall from 59,4mph, in 2015, to 55.1mph, by 2041, if no investment is made.
The government company is already carrying out a number of road upgrades as part of its current five-year funding plan.
The first to benefit will be the A14 between Huntingdon and Cambridge in 2020, as part of a £1.5billion project currently being undertaken.
And between 2020 and 2025, Highways England say another £30billion will be spent to open other expressways including the A3 between London and Portsmouth, A303 between the M3 and M5, and A1 north of Peterborough. Once work is completed, the roads will be re-designated as A(M).
But Bridget Fox, sustainable transport campaigner for The Campaign for Better Transport, criticised the scheme.
“The plans to build big new expressways and convert A-roads to motorways are not the answer to the challenge of connecting our towns and cities,” she said.
“Evidence shows that new roads create new traffic. What we really need is investment in better integrated public transport, walking and cycling for everyday journeys to reduce congestion, to clean up air pollution and create a healthy, thriving country.“
The AA, though, said these new mini-motorways would be “good news” for motorists, as long as they “improved safety and capacity”.
One concern the motoring organisation did raise was that some villages may find themselves increasingly cut off by the potential removal of the shorter slip roads on A-roads.
A spokesperson said that if these access roads were removed, motorists in some villages could potentially face a “five-mile journey being turned into a 25-mile trek”.
For the new road networks to be a success, the AA stressed that Highways England needed to provide a “clear pitch” as to how the expressways will work, and how they will improve capacity and road safety.
President Edmund King added: “Expressways or mini motorways are an effective way of speeding up inter-urban traffic. Putting in grade-separated junctions and slip roads rather than cross roads also makes these roads safer.
“With all the concentration on high speed rail it is about time that our attention and resources are turned to high speed roads.”
Highways England did not respond when asked for comment.
By Will Rimell