MORE cars are to be squeezed onto Britain’s motorways by narrowing existing traffic lanes under a cut-price government plan to tackle congestion.

Instead of widening carriageways by building an extra lane, the Highways Agency will next month reveal proposals to scrap the hard shoulder and mark out four lanes on stretches of motorway in Yorkshire that carry three lanes of traffic.

Each lane will be 6in narrower than at present and vehicles will be forced to adhere to a variable speed limit dictated by congestion levels throughout the day.

The radical plan to increase capacity has prompted concerns from motoring groups. Cars have grown in recent years to fit in more safety features such as airbags and bigger crumple zones.

The scheme is being considered for the M1 between Chesterfield and Leeds and for the M62 between Huddersfield and Leeds. Under the proposals, the hard shoulder will be removed in both directions and emergency refuge areas will be created at regular intervals. A separate 8ft-wide strip will be built into the verge for emergency vehicles.

Using some of the space from the redundant hard shoulder and narrowing the central reservation area, planners will mark out four lanes across each carriageway. They will each measure 11½ft across, compared with 12ft for a standard lane now.

Work on the project is expected to start in 2010 and will cost just under £1.3 billion. Insiders claim this is a “fraction” of the cost of building an additional lane. Conventional lane widening of the M1 has previously cost £36m per mile.