With the concepts of “People-oriented Mobility” and “Mobility as a Service” widely accepted by the public, travelers no longer merely care about the operational efficiency and safety of the urban traffic, but also pay attention to the perceived comfort during the travel. Driving by such demand, some scholars have proposed the concept of “traffic smoothness” to describe the change of driving state during the driving process of the vehicle. However, the relationship between traffic smoothness and the traveler’s perception is not clear so far. In this paper, the concept of traffic smoothness and sudden change of driving state are first clarified, as well as the relationship between them. Then, trajectory data is collected and analyzed. Furthermore, the threshold value of the sudden change of the driving state is defined. The findings in this paper can lay a foundation for the subsequent research on the evaluation method of traffic smoothness.

CICTP