§ Mr. Iain Millsasked the Secretary of State for Transport if he will publish any information held by his Department or by the transport and road research laboratory on the damage to roads related to the dynamic characteristics of truck axles.
§ Mr. FowlerTRRL's published Road Note 29 contains guidance on the structural design of road pavements which includes a method of assessing the damage attributable to commercial vehicle axles. This was based upon the observed life of road pavements which were trafficked by vehicles with specified axle weights. It thus includes appropriate dynamic load effects though these were not quantified in the experiment.
The laboratory is currently engaged on work to determine the magnitude and nature of the dynamic forces applied to road pavements and the way these depend upon the vehicle and design and the profile of the road surface. Recordings of these forces have been obtained with a multileaf suspension and experimental work is continuing on alternative suspension designs. A report is being prepared for publication.