Optimizing Integrated Eco-Driving Control and Holding Strategy for Real-Time Bus Bunching Mitigation

The bunching mitigation and eco-driving of buses have traditionally been treated separately in the literature and formulated in different frameworks. Although a large amount of research has been conducted aiming at providing eco-driving advisory to drivers, impacts of bus operation are not considered. Ignoring the constraints induced by buses could result in transit service irregularity. The present work aims to bridge this gap by formulating optimal control model of buses’ eco-speed and service regularity as a non-linear program. In this study, an integrated bus eco-driving speed and holding time controller is developed to obtain the optimal eco-driving advisory and operational schedule of bus fleet. A bi-level optimization model is formulated for the whole transit line with multiple signalized intersections. The proposed model is solved by a hybrid solution algorithm, which embeds the particle swarm optimization for the upper-level problem and the pseudo-spectral method for the lower-level problem. The proposed controller is tested on real-world cases with the Simulation of Urban MObility (SUMO), and is compared to non-control, speed control, and holding control methods. Simulation results show that the proposed controller reduces the headway deviation by 78.27% and reduces total fuel consumption by 23.95%.