Performance models for roughness progression, rutting, spot sealing, cracking, and patching have been developed for the saskatchewanpavement managmenet information system using the world bank's hdm3 model. A correlation between the saskatchewan riding comfort index and the international roughness index was developed. To separate the environmental effects from traffic effects on roughness, 396 km of asphalt pavements that had appreciably different axle loadings on adjacent lanes were examined. The models have been evaluated using 1976-1987 roughness data and recent maintenance records for the entire paved provincial highway network and 1987 condition survey results from 1, 909 km of roads. A modified rut-depth model retains pavement age as the most significant variable. Cracking and potholing do not develop to a state critically affecting roughness and were excluded from the model. Regression analyses revealed that the last term in thehdm3 model explains most of the roughness deterioration observed inthe field. This is due to grouping of pavement types for model development, which tends to enhance the collinearity between pavement strength and loading data. The age and cumulative axle loading variables were halved because the pavements are frozen half of the time. The calibrated environmental factors m equals 0.035 For the arid southand m equals 0.050 For the humid north of saskatchewan agree with validations of hdm3 by others. Roughness deterioration becomes fasterwith more advanced age of all pavements, but the increase is relatively small for resealed full-depth and asphalt concrete pavements. Thin asphalt mixes laid directly over subgrade deteriorate most rapidly of all pavement types and faster in the northern than in the southern climatic zones. Maintenance models show similar trends. This paper appears in transportation research record no. 1215, Pavement management and rehabilitation.
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