A Traffic Signal Optimization Model for Intersections Experiencing Heavy Scooter–Vehicle Mixed Traffic Flows

In response to the need for designing signal plans for congested intersections caused by heavy scooter-vehicle mixed flows, this paper presents our formulated model for optimizing both the cycle length and signal timings for isolated intersections. The proposed model accounts for the interactions between scooter and vehicle flows and reflects the maneuverability of scooters in the queue formation and discharging process. The robustness of the proposed formulations has been evaluated with field data and laboratory experiments. The signal optimization model, grounded on such formulations for scooter-vehicle mixed flows, has also been implemented at an intersection and assessed with a rigorous before-and-after field analysis. Our research concludes that incorporating the unique properties of scooter flows is essential for design and development of effective signal control strategies to contend with recurrent congestion caused by heavy mixed scooter-vehicle flows.