The ascertaining of the factors that determine the riding-qualities of automobiles and the methods employed in studying these factors and the lines along which research should be directed in an effort to improve riding conditions are proposed in this paper with a view to encouraging further helpful discussion of the riding-qualities problem.
Relative to the first of these questions, the factors treated in this paper comprise (a) road characteristics with respect to the vehicle; (b) the vertical, the longitudinal and the transverse motions of an automobile, as well as small vibrations or oscillations of high frequency; (c) vehicle characteristics, such as springing, accessory control, tires, wheels, chassis frame, seating, body, engine and transmission, steering-gear, brakes, heating, ventilating and lighting.
Four methods most frequently applied to the study of riding-qualities are those employing (a) direct observation by the experimenter, (b) accelerometer measurements, (c) seismograph measurements and (d) photographic analysis, including motion pictures and the photographing of lights suitably mounted upon the vehicle and its load. The requirements that must be fulfilled by instruments in this work are discussed, and several interesting designs of accelerometers and seismographs are described.
In considering the problem of future research, the author mentions as the aims of such investigation (a) accurate analysis of the motions and the forces to which an automobile passenger is subjected, (b) determining as definitely as possible the effects of these motions and forces upon the individual, (c) correlating the conditions with their proper sources and (d) remedying the causes of the uncomfortable or fatiguing conditions. It is shown that, although some study has been devoted to certain phases of the problem, no complete solution has been achieved because of a lack of coordination in the results. Recommendations for future work include (a) a study of the characteristics of vehicle motions with an instrument installation that will record simultaneously both the rotational and the translational effects that may be of importance, (b) an investigation of the effects of the prevailing motions upon individuals, by subjecting a large number of persons to laboratory tests in which riding conditions could be accurately reproduced with suitable apparatus and by studying the results in close cooperation with physiological and psychological experts and (c) an endeavor to apply this information to the investigation of the influence exerted by the various components of the vehicle upon the motions.