The RAC Foundation has said that allowing cars to use the hard shoulder on motorways is not the answer to managing future growth in road traffic.
In a report to coincide with the 50th anniversary of the opening of the first stretch of motorway in the UK, it highlighted the potential problems of concentrating all motorway improvements on areas such as widening and hard-shoulder running.
The foundation said that existing junctions and access roads were unlikely to be able to cope with increased traffic volumes, and pointed out that motorway traffic had grown much faster than the rate of new-road building, which had led to the current high levels of congestion.
The report calls for a focus on developing the motorway network, rather than on improving existing roads. It said that it would be relatively easy for new bypasses to join up with existing main routes, and added that extending the network would allow for higher capacities and service levels.
Professor Stephen Glaister, director of the RAC Foundation, said: "To plan effectively for future roads we must learn from our past failures. We need a better understanding of who is using the network and why, and how our infrastructure in the UK measures up to our European counterparts."
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