Deterioration prediction modeling of Virginia's Interstate highway system

The development of deterioration models for Virginia's Interstate pavements with 7 years of distress data is described. Roadway sections were categorized by pavement type and geographic location, and stepwise regression was used to select the significant predictors of deterioration. Different model forms were examined in an attempt to identify the most appropriate one for fitting the data. The models were evaluated by checking their goodness-of-fit statistics and conducting a series of sensitivity analyses. To further assess the models' accuracy, their predictions were compared against field-observed values. An analysis-of-variance (ANOVA) test was also conducted to compare the accuracies of two model forms and two model adjustment procedures. In general, the developed models provided an adequate fit and generated predictions that conform with accepted engineering judgment. Comparisons with field observations showed their accuracies to be quite reasonable, even for long-range predictions. Finally, the ANOVA results indicated that no significant differences existed between the two model forms tested or between the two adjustment procedures. Although the focus of the research was on developing models for Virginia, the concepts of the study are applicable to any deterioration model development effort.