An Improved Methodology for Measurement of Uninterrupted – Flow Capacity Affected by Pavement Condition

The present Serviceability Rating (PSR) is one of the major criteria in selecting road for rehabilitation. In this paper, statistically realistic models for are developed PSR and free speed correlation on uninterrupted flow facilities. Then, the previously developed relations between free speed and capacity are used to determine the effect of pavement condition on flow capacity. Two nearly identical cars were used and ten raters were selected to evaluate 23 test sections on two major separated roads and an expressway with similar geometric characteristics with a wide range of pavement conditions. Using SAS, it was shown that linear negative exponential models were the best regression models that fit the data according to –R2 and T-test.