Analysis and Modelling of Acceleration Behavior on the Horizontal Curves of Two-Lane Undivided Rural Highways Passing Through Mountainous Terrain

This study has analyzed and modeled the vehicle's longitudinal acceleration behavior of passenger car and loaded truck on the horizontal curves of a two-lane highway passing through mountainous terrain. The acceleration profiles have shown that 98% of the vehicles are either accelerating or decelerating on the curve. The deceleration lengths measured from the point of curvature have shown that the cars and loaded trucks decelerated up to 70% and 40% of the curve length, respectively. The acceleration lengths measured from the point of curvature have shown that the cars and loaded trucks accelerated up to 50% and 30% of the curve length, respectively. The influence of geometric variables and vehicle parameters on the deceleration/acceleration length was analyzed through regression modeling. Results indicate a significant effect of geometric parameters on acceleration/deceleration length. The speed at point of curvature positively impacts deceleration length, whereas the length of the curve and deflection angle have a negative impact. The preceding curve radius, and lane width positively impact acceleration length, whereas the length of the curve has a negative impact. These findings could be used in improving the geometric consistency of a highway alignment.