This paper presents a theory for automated traffic flow, based on an abstraction of vehicle activities like entry, exit and cruising, derived from a vehicle's automatic control laws. An activity is represented in the flow model by the space occupied by a vehicle engaged in that activity. The theory formulates TMC traffic plans as the specification of the activities and speed of vehicles, and the entry and exit flows for each highway section. We show that flows that achieve capacity can be realized by stationary plans that also minimize travel time. These optimum plans can be calculated by solving a linear programming problem. We illustrate these concepts by calculating the capacities of a one lane automated highway system, and compare adaptive cruise control and platooning strategies for automation. The theory permits the study of transient phenomena such as congestion, and TMC feedback traffic rules designed to deal with transients. We propose a "greedy" TMC rule that always achieves capacity but does not minimize travel time. Finally, we undertake a microscopic study of the "entry" activity, and show how lack of coordination between entering vehicles and vehicles on the main line disrupts traffic flow and increases travel time.
Broucke et al. presented a traffic flow theory in automated highway systems and observed that the coordination of vehicles' entrances into a highway can help to improve flows REF .
A theory of traffic flow in automated highway systems
Transportation Research Part C-emerging Technologies
Engineering