Probabilistic Fuzzy Logic Signal and Ramp Metering at a Diamond Interchange

In this paper, a probabilistic fuzzy logic control is developed for the signalized control of a diamond interchange to improve the traffic flow on the surface streets and highways. The signal phasing, green-time extension, and ramp metering are decided in response to real-time traffic conditions. The probabilistic fuzzy logic for diamond interchange (PFLDI) includes the following three modules: probabilistic fuzzy phase timing that controls the green-time extension process of the current running phase, phase-selection logic that decides the next phase based on the presetup phase logic by the local transport authority, and probabilistic fuzzy ramp metering that determines the on-ramp-metering rate based on the traffic conditions of the arterial streets and highways. The advanced interactive microscopic simulator for urban and nonurban network software was used to model the diamond interchange and measure the effectiveness of the proposed PFLDI algorithm. The performance of the PFLDI was compared with that of an actuated diamond interchange (ADI) control based on the asservissement lineaire d'entre autoroutiere (ALINEA) algorithm and a conventional fuzzy logic control for a diamond interchange (FLDI) algorithm. Simulation results show that the PFLDI lowers system total travel time and average delay, improves the downstream average speed, and lowers the downstream average delay compared with ADI and FLDI.