Research on Operating Speed Model for Passenger Car on Deceleration Lane of Expressway

An indispensable index for evaluating the alignment quality and project safety of highways is operating speed. To ensure the coordination and smoothness of speed transitions near expressway exits, the operating speed model for passenger cars on a deceleration lane was studied. Drone and image processing techniques were adopted to collect the data of vehicle speed at expressway exits in Nanjing, and the minimum sample size was determined. K-S testing was performed to examine the normality of speed distribution at featured points, and variation characteristics of speed with travel distance were illustrated. Prediction models of operating speed for passenger cars at the diversion point and shunting nose point were proposed. Finally, the two models were validated through statistical tests. The results show the two models could effectively predict the operating speed of passenger cars at featured points on a deceleration lane, and the prediction meets the requirements for application.