The Highways Agency reported that opening the hard shoulder to traffic at times of greatest congestion has reduced peak-time journeys on a 17km stretch of the M42 by up to four minutes. This was achieved even though traffic volumes grew by four per cent.
Kelly called the scheme a success and said she would extend the scheme to parts of the M6 round Birmingham, at a cost of £150 million.
She ordered a study into whether this type of traffic management could be extended, with hard shoulder running and 50mph limits for smoother, less stop-start journeys.
Campaign for Better Transport roads spokeswoman Rebecca Lush claimed that it would now be very hard to justify motorway widening.
RAC Foundation executive director Edmund King cautiously welcomed the move: "We have seven months of results on a motorway with peak-time congestion. Those with all-day congestion such as the M6 will still need permanent capacity increases."