The Impact of a Congestion Assistant on Traffic Flow Efficiency and Safety in Congested Traffic Caused by a Lane Drop

This article presents the results of a microscopic traffic simulation study conducted to investigate the impact of a Congestion Assistant on traffic efficiency and traffic safety. The Congestion Assistant is an in-vehicle system in which an active pedal supports the driver when approaching congestion and a stop-and-go function when driving in congestion. The authors used an Intelligent Transportation System (ITS) Modeller traffic flow simulation tool to study the effect of the Congestion Assistantin congestion caused by a lane drop. This article describes (a) how the Congestion Assistant operates and (b) the main features of the ITS Modeller. Furthermore, it examines the calibration and validation of the ITS Modeller for congestion caused by a lane drop using traffic flow measurements on a segment of the Dutch A12 highway. Simulation experiments of different penetration rates and system settings show that the stop and go leads to a 30% decrease in travel-time delay at a 10% penetration rate, while the active pedal leads to small reductions in travel-time delay. Compared with the stop-and-go function, the active pedal has fewer sharp accelerations and decelerations, which implies better traffic safety and driver comfort. The effect of the stop-and-go active pedal combination is similar to that of the stop-and-go function on its own. The authors further discuss the implications of the results.