Physics of Autonomous Driving based on Three-Phase Traffic Theory

We have revealed physical features of autonomous driving in the framework of the three-phase traffic theory for which there is no fixed time headway to the preceding vehicle. A comparison with the classical model approach to autonomous driving for which an autonomous driving vehicle tries to reach a fixed (desired or "optimal") time headway to the preceding vehicle has been made. It turns out that autonomous driving in the framework of the three-phase traffic theory exhibits the following advantages in comparison with the classical model of autonomous driving: (i) The absence of string instability. (ii) Considerably smaller speed disturbances at road bottlenecks. (iii) Autonomous driving vehicles based on the three-phase theory decrease the probability of traffic breakdown at the bottleneck in mixed traffic flow consisting of human driving and autonomous driving vehicles; on the contrary, even a single autonomous driving vehicle based on the classical approach can provoke traffic breakdown at the bottleneck in mixed traffic flow.