Automated Merging Control Algorithm: A Cooperative Approach for Connected Automated Vehicles in Platoons

Abstract

Transportation systems are being transformed by advanced vehicular connectivity and automation. Human-driven vehicles are being replaced by Connected Automated Vehicles (CAV). The US Department of Transportation’s (DOT) Intelligent Transportation System Joint Program Office (ITS JPO) promotes automated vehicle research which encourages the development and deployment of automated vehicles by infrastructure-based solutions. Advancements in traffic design and operation can offer solutions to the challenges that CAVs face. An example of these challenges is merging on highways where traffic operation could be enhanced by the use of Vehicle to Infrastructure (V2I) communication between the onramp and the mainline vehicles and roadside units (RSU). This research introduced a way to address the challenge of merging for CAVs in highways using microsimulation. The method proposed makes a contribution to designing an automated merging system that uses V2I communication to make travel time reliable and speed uniform. The designed algorithm assists merging of platoons into a highway adaptively in order to create merging gaps that otherwise would not be available. The simulations were run for the base case without any controller and for several alternatives including slow down on the mainline or onramp, and lane change on the mainline. The programming approach in this research, including Python scripted in Vissim simulation, is a new method to simulate a CAVs environment. The findings showed the maximum flow of 2,402 and 6,369 vph on the onramp and the mainline, respectively with the average speed of 58 km/h by using the automated merging controller. These results were much more pronounced in terms of the big platoon sizes on the mainline where the onramp travel time improved 74%. For platoon desired speed of 60 km/h, using the controller in simulation showed the average onramp speed of 54 km/h which was 55% higher than the scenario with no controller. Moreover, the controller for average platoon sizes of 5 and 6 on the mainline or the onramp successfully helped vehicles to merge without disturbance on the mainline by synchronizing gap availability and onramp vehicle arrival to the auxiliary lane. The results of this research make a contribution to knowledge from theoretical and design perspectives in traffic engineering by promoting a simulation-based approach for CAVs.