A Conceptual Framework with Real-Time Distributed Vehicle Data for Traffic Control

The objective of this paper is to develop an on-line traffic control scheme with real time distributed vehicle data. Though most existing signal systems include some optimization schemes, their performance suffers from inaccurate route travel prediction due to the limitations of data. The commonly used data collection devices like Inductive Loop Detector (ILD) are unable to collect the path-based variables needed for network-level traffic control. In the Persistent Traffic Cookies (PTC) system proposed in UC Irvine recently, those variables can be obtained from the authenticated historical trip tables and current movement information stored in individual vehicles, as written in by wireless hardware at the intersections for vehicles equipped for it. From the inference of each individual vehicle’s historical movements in a network using PTC data, the path-based variables including path flow and path travel time can be predicted. In this study, the improved traffic control schemes with the path-based variables are introduced not only for a single intersection but also for a group of intersections in a sub-network. For a single intersection, the dynamic arrival flow of every movement to an intersection is predicted from the PTC data. Then an optimal signal plan can be determined based on the predicted arrival patterns with the objective of minimizing total delay during a given time horizon. For network-level control, the path flows are estimated from the inference of individual vehicle movement to capture a movement along several intersections. The future path flow can be predicted based on the current path flow and historical data. Based on it, we present a conceptual scheme to group a series of intersections as a sub-network for signal optimization. First, the interaction between any two intersections in a network is estimated by the path flow between them. After choosing a Critical Intersection in a network, a group of intersections having a certain interaction with it is selected and formed a sub-network. The signal optimization in a sub-network is accomplished by a Mixed Integer Linear Problem with the objective to minimize the total delay and a set of constraints. The solution schemes of a problem are discussed base on the results of previous studies.