There are inaccuracies in predicting maintenance and rehabilitation costs for road networks due to the variability and uncertainties in road network condition. To realistically predict maintenance and rehabilitation costs, stochastic characteristics of road network condition should be considered in the estimate. It may, however, not be feasible or practicable to include every single stochastic characteristic of road network conditions in the analysis. To explore this possibility in assessing variations in cost estimates, an analysis was conducted to identify input parameters that are critical for predicting road deterioration condition. Findings indicated that the variability in pavement strength significantly contributed to the variability of predicting road pavement deterioration. Based on this information, discrepancies in cost estimates due to the variability of pavement strength for road maintenance and rehabilitation were subsequently assessed. This paper presents the results of an analysis that was undertaken to identify critical input parameters for road pavement deterioration prediction. The paper also presents a probability method developed for assessing the variation in road maintenance and rehabilitation
