An Investigation into the Variability of Critical Speed and Critical Speed Positions in Four-Lane Hilly Roads

Abstract

One of the crucial aspects in the study of the safety performance of roads in hilly terrain is driver speed behavior. Minimum speed and maximum speed attained on curves and tangents respectively can be considered critical speeds and their positions can be termed critical speed positions for assessment of driver behavior on hilly roads. In the present study, an investigation is conducted to study driver behavior on hilly roads by focusing on the variability of critical speed and positions on different curved and tangent road sections. The present study signifies the finding that considerably higher variability and different trend of variability is associated with the critical speed position on curves and tangents respectively in the case of hilly roads compared to plain roads. Increased variability of critical speed positions substantiates the importance of considering the entire length of curves and tangents in the development of the operating speed prediction model.