An experimental study on Max-Pressure traffic controller based on travel time delays

First, this paper develops and examines a new travel time-based traffic signal controller. By applying a decentralized approach that relies solely on local information, the controller optimizes phase duration to maximize throughput. Three issues from previous queue-based max-pressure controllers are addressed: (i) infinite link capacity, (ii) non-fixed phase sequences, and (iii) the neglect of spatial distribution of the queues. The newly developed cyclic time-based max-pressure control is compared with existing cyclic queue-based and time-based max-pressure schemes. The results show that the introduced time-based approach offers improved fairness and more effective decision-making. Second, new time-varying schemes are developed for the time-based max-pressure controller: bounded cycle lengths, which impose stability-preserving minimum and maximum limits, and unbounded cycle lengths, which dynamically adjust based on real-time traffic flow for enhanced flexibility. A comparative analysis with fixed cycle length schemes highlights the advantages of appropriate cycle length allocation for improved performance. Finally, the developed controller was evaluated through simulation tests and an experimental case study in an urban traffic network, specifically at a complex T-intersection. The intersection, which was originally controlled by loop detectors, was isolated from adjacent intersections for the experiment, with the loop detectors disconnected. Traffic control was instead managed using Bluetooth data, providing real-time travel time information and enabling the intersection to adapt to current traffic conditions while complying with traffic regulations and constraints. The results demonstrated that, despite the constraints, the adaptive controller performed more effectively than the actuated controller, providing a cost-effective solution for traffic control.