Joint Optimization of Stop Design and Lane Assignment for Buses with Different Directions at a Signalized Intersection

AbstractThe common practice of buses to different directions dwelling at the same stop on an intersection approach may cause serious traffic bottlenecks, where buses queue to pull in and aggressively change lanes for their target exit. To address this problem without changing the bus route for passenger convenience, the study proposes an extended cell transmission model to explore the optimal bus stop design and lane assignment at an isolated signalized intersection. Specifically, vehicles are categorized as cars or buses dwelling on the intersection approach or the exits, and various interactions between them are carefully captured. The effect on mixed traffic of bus dwelling and aggressive lane changes after pulling out is revealed with lane blockage as well as reduced cell receiving and sending capacities. Considering significant mixed traffic stochasticity, a competitive gradient bandit algorithm is established to compare the feasible solutions of the proposed model, where the weight of better solutions is gradually increased, whereas that of others is correspondingly reduced as proven with mathematical calculation. A case study follows to validate that the proposed algorithm is efficient and accurate in identifying the optimal solution, in comparison with Monte Carlo tests. This research provides insights into improving bus stop design and lane assignment at signalized intersections to promote the efficiency and mitigate the conflicts of mixed traffic.