Traditionally the riding qualities of a pavement are expressed as some function of localized irregularities in the contour of the pavement surface. This is predicated on the fact that the portion of passenger comfort or discomfort imparted by all features of the pavement surface can not be isolated and determined separately from other influences such as vehicle characteristics or psychological and physiological aspects of the passenger himself.

Measurements of riding qualities have dealt almost exclusively with vehicle displacements in the vertical direction only, these having been and still being the most prominent and most amenable to measurement. By this procedure displacements in other directions have been ignored, although their relative influence on riding comfort as determined by comfort research is known to be great.

During the past few years certain features of highway construction and use have emphasized surface irregularities that cause significant amounts of combined transverse and longitudinal motion. In response to this developing need for determination of riding qualities on the basis of component motions, an instrument for measuring and recording induced accelerations in the three principal directions was developed and adapted to a passenger vehicle. This paper describes the equipment and its use in evaluating riding qualities of various pavements in Kentucky.

Report Date


Report Number

No. 106

Digital Object Identifier



Paper presented at the Annual Meeting of the Highway Research Board in Washington D.C. (January 11-14, 1955).