ROAD SAFETY TESTS

Evening Star, Issue 22722, 9 August 1937, Page 15

ROAD SAFETY TESTS

DATA MTAHHED IY NEW MACHINES Road safety -'experiments and road , construction improvements are described in the second annual report of the Road Research Board, issued by the British _ Department of ‘ Scientific and Industrial Research. Dr R. E. Stirling, the director of research, in surveying materials and methods of road construction, states that though in recent years there has been a rapid advance in the methods of highway engineering, the absence of sufficient scientific knowledge has led engineering works in many cases to be designed on insufficient data, and progress has thus had to he made by the wasteful expedient of hit or miss procedure. The work of the Road Research Board aims at the formulation of an accurate science of road engineering. “ Many road failures,” the report says, “ have been shown to be due to the imposition’ on existing roads of loads much greater than those for which they were intended, with the result that the foundations - have given way. This is not surprising when the evolution, of many of the roads in the country is considered. They started first as cart tracks, were converted to water-bound, "macadam, and then treated with repeated surface dressings of tar or- bitumen, or covered with tar macadam or concrete.” ' The report adds that before the foundation of a new road can be. economically designed knowledge of the properties of the subsoil is requiste, , and before the best niethod of treating an existing road can he devised similar information is necessary on the subsoil and also on the supporting power of the existing structure. It is stated that a machine has. been devised, which, -by means of vibrations, can ensure the production of constant water content for sand and stone before mixing, thus marking progress towards consistent quality. STUDY OF SKIDDING. Three special machines are now In use for experiments, for, as the report says, “ Although the road structure itself may bo in a satisfactory condition, it may bo unsatisfactory "from the user’s point of view, because it is slippery, or because it gives.#,‘ rough, jide,.’. due. t(j surfadeirregularities' Other desirable features of road surfaces are light colour, and continuity of surface conditions. All these points have a bearing on road safety.” For the . study of skidding a standard machine, consisting of a motor cycle and sidecar combination, has been developed by which records of the measure of friction . between the tyre of - th© side car and the road can be made under practical conditions up to a speed of 30 miles an hour. Experiments with the machine have given values which agree with the normal experience of rood users, and a theoretical study has been undertaken to explain the .various effects, but only a partial proof has as yet been supplied. • Considerable progress has been made in the experimental stages, • according to the report, and the work is now entering a phase of application. The knowledge already obtained, it is stated, has been or real service in enabling comparisons of vanous types of roads to be made and thus helping towards the ultimate goal.