§ Mr. Boothasked the Secretary of State for Transport (1) whether he will order research to be undertaken into the strains imposed on the road surface during the cornering of articulated lorries with tri-axle trailers with axle spacing of at least 2.7 metres and loadings of up to 22.5 tonnes and also into the dynamic underground stresses imposed by such lorries when cornering, especially where there is surface discontinuity;
(2) whether he has initialed research into the effects of road surface discontinuity on the generation of ground vibration from heavy vehicles as promised in the Department's evidence of January 1980 to the Armitage inquiry; and, if not, whether he will instruct this to be done.
§ Mr. FowlerResearch on the effects of surface discontinuity on ground vibration is included in the programme of the Transport and Road Research Laboratory. Some results of a study of the forces involved in the cornering of multiple-axle vehicles have been published by TRRL in report No. SR483. Any tri-axle will scrub the road surface when cornering, particularly if it does not have a steered axle, but the effect is confined to road surfaces. Stresses induced in the lower layers of the road pavement are largely related to individual axle loads, which would average 7.5 tonnes for a 22.5 tonne tri-axle.
§ Mr. Boothasked the Secretary of State for Transport what consideration he has given to the inclusion of the cost of traffic delays caused by motorway repairs in the road trunk costs allocated to lorries according to their damage factor; and how much this would add to their costs if it were included for the two most recent years for which figures are available.
§ Mr. FowlerI regret that the data on which such costs could be adequately quantified are not available.