Data-Driven Integrated Control Strategy for Postponing Early-Onset Breakdowns on Urban Expressway On-Ramp Bottlenecks in Shanghai

Abstract

Previous studies have shown that Shanghai expressway on-ramp bottleneck’s pre-queue flow is much lower than that of similar facilities in US. The objective of this paper is to design a data-driven control strategy for combining ramp metering (RM) and variable speed limits (VSL) to postpone the early-onset breakdown at urban expressway bottlenecks in Shanghai. The breakdown probability prediction model is extended via a flow based regulator model to control the collective vehicle speed of mainline traffic. The proposed strategy was tested at two expressway recurrent bottlenecks using the VISSIM microscopic simulation. The proposed strategy postponed the breakdown time by 10 minutes compared to 2–5 minutes achieved by ALINEA strategy. Additionally, the proposed strategy increased the pre-queue flow by 12.9% to 18.1% and reduced total travel time by 4.7% to 14.7%.