Person-Based Traffic Responsive Signal Control Optimization

This paper presents a person-based traffic responsive signal control system for transit signal priority (TSP) on conflicting transit routes. A mixed-integer nonlinear program (MINLP) is formulated, which minimizes the total person delay at an intersection while assigning priority to the transit vehicles based on their passenger occupancy. The mathematical formulation marks an improvement to previous formulations by ensuring global optimality for undersaturated traffic conditions and intersection design and traffic characteristics that lead to convex objective functions in reasonable computation time for real-time applications. The system has been tested for a complex signalized intersection located in Athens, Greece, which is characterized by multiple bus lines traveling in conflicting directions. Testing includes cases with deterministic vehicle arrivals at the intersection and emulation-in-the-loop simulation (EILS) tests that incorporate stochasticity in the vehicle arrivals. The results show that the proposed person-based traffic responsive signal control system reduces the total person delay at the intersection and effectively provides priority to transit vehicles, even when perfect information about the auto and transit arrivals at the intersection is not available.