Assessing 'road-friendliness': a review

This paper is concerned with assessing the dynamic tyre forces generated by articulated heavy goods vehicles for road damaging potential. Various factors are discussed, including: (a) general testing methodologies; (b) road damage issues such as 'spatial repeatability' of dynamic tyre forces and road damage criteria; (c) vehicle response issues, such as test duration and sampling details, road roughness, testing speed, wheel-base filtering, tractor-trailer interaction, suspension maintenance and 'indirect' testing methods; and (d) implementation issues. It is concluded that the most practical method of assessment testing would be to use a 'type approval' test to measure the vehicle's peformance when coupled to a standard trailer or tractor unit, combined with anual inspections of hydraulic damper integrity. The type approval procedure should use simple single-axle laboratory tests to estimate the parameters of a generic mathematical model of each vehicle unit. Numerical simulations of the tractor and standard trailer (or trailer and standard tractor) should be used to determine the vehicle's response to a variety of typical road input conditions. These responses should than be assessed using realistic road damage criteria to determine an 'in-service' road damage index.