§ Mr. AdleyTo ask the Secretary of State for Transport what research his Department has carried out into the relative damage caused to road surfaces by different classes of road vehicles; and if he will give specific details for(a) motor cars of 1300 cc engines and (b) loaded 20 ton commercial vehicles.
§ Mr. Kenneth CarlisleThe research commissioned by the Department is recorded in the following two reports, copies of which are being made available to the Libraries in both Houses:
- (a) "Relative Damaging Power of Wheel Loads in Mixed Traffic" (TRL Laboratory Report 979, Crowthorne, 1981).
- (b) "Trends in Axle Loadings and Their Effect on Design of Road Pavements" (TRRL Research Report 138, Crowthorne, 1988).
The results of that work have broadly confirmed and extended the original work on this topic undertaken in the United States of America between 1958 and 1961.
All motorcars, whatever the size of their engine, cause negligible road wear and tear compared with commercial vehicles.
218WThe relative wear and tear caused by fully laden commercial vehicles in the 20–tonne range is indicated by the following vehicle wear factors expressed as the number of standard 80KN axles.
Factors Two axle rigid (maximum gross weight 17 tonnes) 3.14 Three axle rigid (maximim gross weight 26 tonnes) 3.44 Three axle artic (maximum gross weight 26 tonnes) 4.50