Developing Roadway Standards for Ride Quality from the Customer's Perspective

Abstract

This paper reports the findings of research conducted for the Pennsylvania Department of Transportation (PennDOT) to develop customer-based standards for ride quality on four functional classes of highway: Interstate highways, other national highway system (NHS) roads, secondary roads with average annual daily traffic (AADT) greater than 2,000, and secondary roads with AADT less than 2,000. The field work, in which subjects evaluated the ride quality of predetermined test sections of pavements, was conducted in six Pennsylvania counties to incorporate a variety of settings across the state. These subjective ratings were regressed on international roughness index (IRI) values for each of the four highway classes and revealed a fan-shaped pattern in which motorist satisfaction with ride quality dropped off with increased roughness most sharply on Interstate highways, less so for other NHS roads, and still less for secondary roads. PennDOT's current standards for what constitutes good ride quality for each o...