§ Mr. Dodsworth
asked the Minister of Transport why the use of "Delugrip" surfacing is considered unsatisfactory for high speed roads in the light of the fact that this material is now in use on a British international motor racing circuit.
§ Mr. Kenneth Clarke
"Delugrip" has not been used in high speed roads because full-scale trials carried out so far by TRRL have failed to produce the surface texture considered to be necessary to provide adequate skid resistance. Trials are continuing.
Requirements for a motor racing circuit are different from those for roads and depend more on the achievement of optimum traction in dry conditions than on skidding risk during wet conditions. Racing car tyres are selected according to wet or dry surface conditions.