22. Ramp metering for lane-free traffic of automated vehicles via ramp vehicle speed control

The videos included in this playlist are part of the results discussed in the paper titled "Ramp metering for lane-free traffic of automated vehicles via ramp vehicle speed control". Ramp metering stands as one of the most effective methods for managing and controlling traffic flow within conventional traffic management systems. By controlling the outflow of on-ramps, ramp metering aims to prevent traffic congestion and maintain the density of merging traffic near its critical value, thus maximizing the throughput. In conventional implementation of ramp metering, a traffic light serves as the actuator to control traffic flow. In this regard, the advent of connected and automated vehicles allows for leveraging variable speed control as a means of applying ramp metering. In this study, a new ramp metering method for Connected and Automated Vehicles (CAVs) driving in a lane-free environment is presented, using speed control of ramp vehicles as the ramp metering actuator. In this context, two feedback control strategies are introduced; the first one controlling the ramp flow and subsequently translating this into the desired speed of ramp vehicles (indirect control); and the second one regulating directly the desired speed of vehicles in the ramp area (direct control); both in response to the current mainstream density. Three cases are depicted in the respective videos, illustrating the situations without control, direct control, and indirect control. The videos focus on the ramp merge area. The videos are shot around the time of the speed breakdown in the no-control case, caused by excessive overall (mainstream plus ramp) demand. As can be observed, the implementation of ramp metering effectively avoids the onset of congestion.