Empirical study on car-following characteristics of commercial automated vehicles with different headway settings

Fundamental Diagrams of Commercial Adaptive Cruise Control: Worldwide Experimental Evidence

“…Therefore, the result here further supports our conjecture above that the s − v for ACC is not a single linear relationship for the entire speed range. Our conjecture is also consistent with Shi and Li (2021), which found that the calibrated ACC controller varies with speed. Further research along this line is needed.…”

“…It was observed that the ACC platoon can be cut in by surrounding human-driven vehicles even with the smallest headway setting, implying that the ACC vehicles may have a relative large time gap. Shi and Li (2021) recently conducted a set of three-vehicle platoon experiments with two commercial Lincoln MKZ ACC cars. It was found the platoon became more unstable as the headway was set to a smaller value.…”

Multianticipation for string stable Adaptive Cruise Control and increased motorway capacity without vehicle-to-vehicle communication

“…The reaction time of such systems has been observed to be similar to that of a human driver ( Makridis et al, 2018 , Makridis et al, 2020 ). Furthermore, different research teams, working in parallel, have produced data showing that commercial ACC systems are indeed string unstable ( Makridis et al, 2020 , Gunter et al, 2021 , Shi and Li, 2021 , Ciuffo et al ).…”

“…With more research dedicated to the issue of string stability and automated driving, a very troublesome trade-off has become apparent between string stability and capacity. Larger time-gap settings tend to lead to more string stable platoons ( Shi and Li, 2021 , Makridis et al, 2021 , Zhou et al, 2104 ). However, vehicles maintaining large time-gaps would negatively affect the capacity, decreasing the potential traffic flow ( Mahmassani, 2016 ).…”

“…The paper’s goal is thus to examine how effectively the second leader position and velocity information could be exploited to enhance current ACC systems. To this end, we approximate the functioning of the ACC car-following behavior exploiting a linear model that is used in the literature by the vast majority of studies concerning commercial ACCs system ( Shladover et al, 2012 , Gunter et al, 2021 , Shi and Li, 2021 ). Despite there might be more performing car-following models, we deliberately decided to adopt the linear modeling framework given the supporting evidence suggesting its capability of replicating the real-world behavior observed for such systems, and the stability analysis that the linear formulation can afford.…”