The First Report of the Road Research Board
Page 39
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THE Department of Scientific and Industrial Research issued, last Monday, the first report of its Road Research Board covering the two years ended March 31, 1935, since the Department assumed responsibility for the research work on roads carried out at the Road Research Laboratory, Harmondsworth, Middlesex.
Much attention is given in the report to the problem of skidding. The work aims at determining the factors in vehicle design which induce' skidding, and those in road, construction and conditions favourable to this trouble and which must be avoided.
A special motorcycle combination was utilized, but it is stated that an obvious method of continuing the research would be to skid .full-sized vehicles on a large surface. This would be expensive and somewhat dangerous, but may have to be faced. Another type of equipment consists of a singlewheel trailer used with circular-track road-testing machines, or for attachment to the rear of a testing lorry.
A surprising result of the work is that it has been proved that in wet weather roads are, in general, more slippery in summer than in winter. The surface film on the road acts as a lubricant, and information is being sought regarding the component parts of this which induce skidding, how it is formed, and how this formation can be prevented. A special machine has been designed for this work, and P. can be operated with any type of lubricant desired ; for example, the surface water squeegeed from a wet road, or a solution or suspension of any road-making ingredient.
Little progress in the general research on roads will be possible until some means are available for judging durability, other than by waiting for deterioration under normal usage. A speedy method is to employ road-wear machines, which on sample road sec
tions will give a wear in days equivalent to years of normal use.
A large testing machine with a track 110 ft. in diameter is being built, This will allow a close approach to actual road conditions, and the -testing " tpol " will be a lorry travelling at 45 m.p.h. and loaded up to 10 tons. It will be tethered to a centre post and driven around a track 10 ft. wide.
'rests have been conducted to determine the value of• the forces and the vibrations transmitted to roads by vehicles of various types, and to correlate the results with the type of pavement, sub-soil, etc. Towing a trailer with a back-axle load of 3 tons over a plank 1 in. thick showed that there are• two impact peaks; the first When a wheel strikes the object, the second when it drops again to the road. At 25 m.p.h., the first reached a maximum of 1.75 the static load. The second peak was at a maximum of 2 to 2.25 the load at 20 m.p.h.