Supervisory multi-class event-triggered control for congestion and emissions reduction in freeways

The paper addresses the problem of regulating traffic in freeway networks via multi-class ramp metering with the objective of reducing both congestion and traffic emissions. The proposed control scheme includes a supervisor, acting at a higher level, which receives measurements from the network and periodically makes a prediction on the system evolution. At the lower level, local feedback controllers compute the control action on the basis of measurements in a neighbourhood of the on-ramp. The neighbourhood is communicated by the supervisor in real time, according to an event-triggered logic. The effectiveness of the proposed control scheme is assessed through simulation results, properly discussed in the paper.