Local and coordinated ramp metering within the unifying framework of an adaptive control schemeLocal and coordinated ramp metering within the unifying framework of an adaptive control scheme Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2020-04-102019enThis study develops and proposes a unifying control scheme to address the ramp and mainline metering problems arising in freeways. A distinguishing novelty of the proposed approach is that it can inherently be applied both at local and coordinated levels. The proposed strategy is based on a recently developed nonlinear adaptive control scheme, consisting of a nominal feedback law in conjunction with a nonlinear observer, which aims to estimate some unknown system variables. The present study provides insights into and demonstrates the properties and the performance of the proposed methodology, which is tested for realistic traffic scenarios using a macroscopic traffic flow simulator as a surrogate for potential field application. Comparison tests have been performed with other control strategies proposed in the literature and employed already in the field.http://creativecommons.org/licenses/by/4.0/Transportation Research Part A: Policy and Practice128October 201989-113 Kontorinaki Maria Κοντορινακη Μαρια Karafyllis Iason Καραφυλλης Ιασων Papageorgiou Markos Παπαγεωργιου Μαρκος Elsevier Adaptive control scheme Coordinated ramp metering Local ramp metering Nonlinear traffic control