Experimental studies of objective and subjective passenger response to various fore-and-aft, or longitudinal, vehicle acceleration transients are reviewed. It is found that the wide variability in type of study and form of results does not allow conclusive statements to be made regarding passenger acceptability of any specific acceleration—jerk profile in a given transportation system.

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A Survey of Longitudinal Acceleration Comfort Studies in Ground Transportation Vehicles

Various methods for evaluating ride quality in automobiles are investigated by means of a field study involving two different automobiles, seventy eight different passengers, and eighteen different roadway sections. Passenger rating panels were used to obtain subjective evaluation of the various rides, and measured vibration spectra were compared on the basis of various evaluation techniques to determine their ability to predict the subjective ratings. Included in the evaluation criteria considered are the ISO (International Standards Organization) Standard, the UTACV (Urban Tracked Air Cushion Vehicle) Specification, and the Absorbed Power method of Lee and Pradko. Excellent correlation was found to exist between the subjective ride ratings and simple root mean square acceleration measurements at either the vehicle floorboard or passenger/seat interface. Equations were developed to predict the subjective ride rating from measured vibration spectra.

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The Prediction of Passenger Riding Comfort From Acceleration Data

This study investigated the effect of visual distraction on reaction time to a target stimulus in a simulated traffic environment. Subjects viewed slides of simulated roadside signs, some of which included a traffic stop sign. Reaction time was measured to their “stop” or “go” response. As predicted, the number and color of distractors, as well as the proximity of distractors to the target stop sign, all had significant effects on reaction time: In addition, all two-way interactions between the distractor dimensions were statistically significant. Practical suggestions for reducing visual distraction in the traffic environment are discussed.

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Effects of Visual Distraction on Reaction Time in a Simulated Traffic Environment

The purpose of this study was to investigate systematically the relation between roadside signs located nearest to urban traffic intersections and traffic accidents. Specific sign elements studied were total number, type (public versus private), size, and color. The dependent variable was the number of accidents during 1975 at 60 intersection approaches where the driver who entered the intersection from the direction selected was determined to be at fault in the police accident investigation report. The intersections were selected randomly from cross intersections in the city of Austin where at least one accident occurred during 1975. Results indicate that a number of sign elements had a significant relation to accidents at intersections controlled by stop signs, but no relation was found between signs and accidents at intersections controlled by traffic signals. Possible interpretations of the findings are considered, and some practical suggestions for reducing the effects of distracting signs at stop-sign intersections are advanced. /Authors/

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Relation between roadside signs and traffic accidents: field investigation

For a more complete description of this work and its contents, please view the details in the Center for Transportation Research Library catalog: http://library.ctr.utexas.edu/dbtw-wpd/query/id/5762

The Influence on Rural Communities of Interurban Transportation Systems

A brief discussion of the various inputs that affect ride quality and the need for ride quality criteria is given. Isolation of the human in any vehicle from undue vibration is an important criteria for ride comfort. Some current passive isolation systems are discussed in the context of seat-man models for automobile vibration isolation. Usual passive isolation systems use a combination of linear springs and viscous damping elements. Active vibration isolation through the use of feed-back controls using relative displacement or accelerations on tractor seats by C.W. Suggs and L.F. Stikeleather and jet transport seats by P. Calcaterra is discussed. In conjunction with both the active and passive vibration isolation systems static comfort is maintained with seat cushions. Alleviation of compression fatigue can be achieved through moveable and adjustable seats and dynamic cushions. Human body mechanistic modeling by Coerman, Dieckman, Stanley Aviation, and Suggs is presented. Experimental parameter determination of the limped mass models of the human through the use of mechanical impedance is discussed. Recent modeling by Jex and Allen of the human through behavioral techniques for research into operator control capabilities in a dynamic environment and its potential for correlation with subjective ride quality measurements is discussed. A survey of state of the art seat-man modeling for impulsive loading consisting of work done by Cornell Aeronautical Laboratory, Jack Collins and James Turnbow is given.

A Healey

Papers

Literature survey on passenger and seat modeling for the evaluation of ride quality