Studies of riding qualities as determined by irregularities in high type bituminous pavements were first treated in Report No. 1 on this subject in December, 1949. At that time interest was centered as much on specifications as on the causes, the thought being that specifications did not provide satisfactory tolerances to produce surfaces with good riding qualities. Specifically, tolerances over relatively short distances longitudinally were though to be at fault.

It was found early in that work that variations in the lateral direction were causing considerable roughness but since longitudinal variations were being studied primarily, no actual measurements were made to evaluate roughness produced by non uniform cross-sections.

This year much work has been directed toward the development of a device for automatically measuring, analyzing, and recording roughness based on human comfort tolerances. Considerable effort has been spent on designing effective equipment or devices for controlling the pavement cross-section.

Report Date


Report Number

No. 60

Digital Object Identifier