Free flow acceleration: Humans and car-following models

Abstract

Increasing penetration of connected and automated vehicles on the road, which is expected in the near future, could lead to a complete transformation of surface transport. From the political perspective, there is an increasing expectation that this transformation would help make transport systems more efficient from an economic, environmental and social perspective. Researchers in the traffic community are therefore called to follow this process and provide assessment tools able to capture the effect of such technologies. As a first step, since many new technologies have an impact on vehicle dynamics, traffic models should be able to better reproduce the microscopic vehicle behavior (and not only the behavior of the traffic). The present paper tries to contribute to this evolution by showing the limitations of different well-known car-following models in reproducing the vehicle acceleration dynamics. The findings raise concerns about the capability of current traffic models in assessing the effect on traffic and on the environment of technologies having an impact on the vehicle dynamics. They also highlight the need for a deeper integration of traffic and vehicle models in order to explicitly take into account the way in which vehicle technologies operate in their interaction with the driver.