A Dynamic Competition Control Strategy for Freeway Merging Region Balancing Individual Behaviour and Traffic Efficiency

Abstract

An integrated control strategy is considered in this paper with the aim of solving congestion in freeway merging regions during peak hours. Merging regions discussed in this paper include the mainline and on-ramp. Traditional research mainly focuses on the efficiency of traffic, ignoring the experience of on-ramp drivers and passengers. Accordingly, a dynamic competition control strategy is proposed to balance individual behaviour and traffic efficiency. First, the concept of the congestion index is introduced, which is expressed by the queue length and the speed parameter of the merging region. The congestion index is used to balance the priorities of the vehicles from the mainline and on-ramp into the merging region in order to avoid poor individual behaviour of on-ramp drivers due to the long-time waiting. Additionally, a nonlinear optimal control approach integrating variable speed limits control and ramp metering is proposed to minimize the total time spent and the maximum traffic flow. The integrated control approach proposed in this paper is tested by simulation which is calibrated using field data. The results indicate that the integrated control approach can effectively shorten the total delay and enhance the traffic service level.

Influence of Spatial Placement of Variable Speed Limit Zones on Urban Motorway Traffic Control

“…Variable Speed Limit (VSL) is a traffic control approach derived from the ITS domain that uses Variable Message Signs (VMS) to apply appropriate speed limits on urban motorways based on the current meteorological and/ or traffic state. VSL can be integrated and operated synchronously with other ITS services such as Ramp Metering to provide more efficient traffic control if VSL is unable to maintain the desired flow capacity within the congested motorway section [5]. In general, VSL is used to harmonise the speeds of congested downstream traffic and upstream free-flow traffic and to mitigate the occurrence of congestion and shockwaves, as described in [6].…”