THE EARL OF HARROWBYasked Her Majesty's Government:
Whether the new safety provisions as between the up and down lanes on the motorway can be made by a widish ditch, two or three feet deep, of mud and water with brambles above them, to act also as anti-glare, rather than metal partitions where the damage would be far greater.
§ LORD MOWBRAY AND STOURTONThe basic requirements of a safety barrier are that it shall contain a 3,000 lb. vehicle travelling at 65–70 m.p.h. striking it at an angle of 20 degrees and redirect the vehicle to a course as nearly parallel as possible to the line of the barrier, without the vehicle overturning or rebounding, and in such a way that the collision forces are tolerable to the vehicle occupants. The type of barrier which will generally be installed on motorways central reserves is designed to satisfy these requirements. The width of ditch which could be provided within the central reserve would overturn fast vehicles into the opposite carriageway and mud and water and brambles would add little resistance to the passage of vehicles.