Two generalised models predicting roughness progression in flexible pavements are developed from the comprehensive and widely validated set of incremental and interactive pavement distress functions in the Highway Design and Maintenance Standards model. These are summary models intended for use in pavement management applications and as a performance model for pavement design. The first retains most of the powerful capability of the original incremental model and has a very close fit to it, using traffic loading, strength, age, environment, rutting, cracking, and patching to predict roughness at any pavement age. Variants, which can be used when one or more of the distress parameters are missing, are also presented. The second model is simpler and generally structural, omitting surface distress parameters and compensating for this through the primary structural, traffic, age, and environmental factors. It is adequate for use where moderately good maintenance standards are being applied but has an error six times larger than the full model when extended over the full range of distress. (A)
Abstract