CCV: A New Model for S85 Prediction

Design Consistency analysis considers variations in speed on road alignments to make considerations about road safety. Safety Criteria allow to express a judgment on road alignment homogeneity on the basis of the comparison between design speed SD and operating speed S85 along the alignments (operating speed is represented by the 85th-percentile speed of a sample of vehicles). In this paper a new predictive model, CCV, is proposed to determine the operating speed S85, also for the alignments whose characteristics of main geometric elements are not known. The application of CCV model on discretized data allows a fast recognition of operational speeds inconsistencies.