§ Mr. Wilkinsonasked the Secretary of tate for the Environment what are the types of motorway safety barrier currently in service on British motorways; and to what relative angle and speed of impact has each been tested by a manned vehicle in the course of trials sponsored by his department.
§ Mr. Graham PageWith the exceptions of a short length of the M1 (18 miles) and at bridges and embankments which are equipped with barriers of the blocked-out beam system and part of M62 which is equipped with the wire rope type of safety fence, all installations on British motorways are of the tensioned beam type.
Testing has been undertaken by the Road Research Laboratory with a manned vehicle. In the early days of the research into the blocked-out beam system a 3,000 lb. manned vehicle was crashed at 30 m.p.h. at an angle of 20°. For the tensioned beam system at the same speed the angle was not greater than 10°. This particular experiment was undertaken to test a single post in the system.
Most of the experimental work has been done with remote controlled vehicles 406W of approximately the same weight and tests have been made at various speeds up to 70 m.p.h. at an angle of 20°.
Full details of these tests have been published and are conveniently summarised in an article in "The Surveyor and Municipal Engineer", Vol. CXXX, No. 3935, 4th November, 1967. Evaluations made at the Road Research Laboratory and elsewhere of various types of safety barriers and fences are described in an article in "Traffic Engineering and Control" 1964, Vol. 5, No. 9.