§ 44. Mr. Charles A. Howell
asked the Minister of Transport what reports he 1452 has received from the Road Research Laboratory regarding the water-holding propensity of the various types of surface on M.1; and what are his conclusions regarding future motorway surfaces.
§ Mr. Marples
The Road Research Laboratory has not yet completed its investigations. Our later motorways are being built with higher standards of drainage and a steeper slope from the centre. Central reserve drainage has been extended to the full length of M.1. These measures should help to combat the spray nuisance caused by water on the carriageways in periods of heavy rainfall.
§ Mr. Howell
Was the camber of this road wrong from the very start? Many of us who use the M.1 frequently after rain find that, even with this new irrigation, if that is the proper word, in the centre lane the water is still there. When motorists are called upon to brake rapidly, as they frequently are because of obstructions on the road, it becomes very dangerous. Is the camber the cause?
§ Mr. Marples
It is part of the civil engineering problem. The cross-fall on M.1 is 1:48, which is generally steeper than on Continental motorways. On motorways designed now the cross-fall on the carriageway has increased to 1:40, with an even steeper cross-fall on the hard shoulder. The cross-fall is the slope of the carriageway from the centre of the motorway to the side. We are increasing it.