Vehicles Trajectory Oscillation Characteristics and Passenger Cars' Lane Width for Freeways

To clarify the trajectory lateral oscillation behavior of vehicles during lane-keeping driving on freeways, vehicle trajectories and driving speed were extracted using the dataset of the vehicle position coordinates from drones. The index of vehicle trajectory oscillation characteristics under normal driving conditions was then calculated, including the lateral amplitude of trajectory oscillation and traveled distance within the oscillation cycle. The speed distribution characteristics of different vehicle types and the effects of speed and lane positions on the trajectory lateral oscillation indexes were analyzed. The results show that: although there are significant differences in body size and power performance between light vehicles and large vehicles, their trajectory oscillation amplitude is nearly the same. The average oscillation amplitudes of the two types of vehicles are 0.587 m and 0.560 m, and the traveled distances within the oscillation cycle are 252.95 m and 251.99 m, respectively. The lateral oscillation amplitude of vehicle trajectory is insensitive to the speed change and will not increase with the increase of speed. It tends to be smooth or even decrease under high-speed conditions. Similarly, there is no significant correlation between travel distance and travel speed during the oscillation cycle. Different lane positions have an impact on the trajectory oscillation behavior, for light vehicles, trajectory oscillation increases when the vehicle position changes from the inside lane to the outside lane; while for large vehicles, the trajectory oscillation is the smallest in the middle lane. The trajectory oscillation of the Chinese freeway measured in Chongqing is slightly higher than the one calculated from the German HighD data set, but they are very close on the whole. According to the characteristics of the lateral amplitude of the vehicle trajectory, the proposed values of lane width for light cars dedicated lanes or passenger car freeways can be determined, the minimum and general value of lane width for passenger car dedicated lane with a design speed of 100~120 km·h-1 is 3.0 m and 3.25 m. © 2023 Science Press. All rights reserved.