Maximizing bus discharge flows from multi-berth stops by regulating exit maneuvers

• Published in: Transportation research. Part B: methodological Vol. 56; pp. 254 - 264
• Main Authors: Gu, Weihua, Cassidy, Michael J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-10-2013; Elsevier
• Subjects: Applied sciences; Bus-stop capacity; Bus-stop congestion; Bus-stop exit maneuvers; Bus-stop queueing models; Exact sciences and technology; Ground, air and sea transportation, marine construction; Road transportation and traffic; Transportation planning, management and economics; Bus-stop capacity; Bus-stop queueing models; Bus-stop congestion; Bus-stop exit maneuvers; Bus; Modeling; Passenger transportation; Road transportation; Traffic flow; Simulation; Queueing system; Capacity; Analytical method; Bus stop; Traffic congestion
• ISSN: 0191-2615; 1879-2367
• DOI: 10.1016/j.trb.2013.08.005

•Bus stops where buses can exit by overtaking other buses are examined.•Analytical models are formulated to predict bus capacities of these stops.•The capacities are compared against those where overtaking maneuvers are prohibited.•Findings from this work are at odds with the literature.•Policies for maximizing bus-carrying capacities of these stops are examined.
Upon having loaded and unloaded their passengers, buses are often free to exit a multi-berth bus stop without delay. A bus need not wait to perform this exit maneuver, even if it requires circumventing one or more other buses that are still dwelling in the stop’s downstream berths. Yet, many jurisdictions impose restrictions on bus entry maneuvers into a stop to limit disruptions to cars and other buses. Buses are typically prohibited from entering a stop whenever this would require maneuvering around other buses still dwelling in upstream berths. An entering bus is instead required to wait in queue until the upstream berths are vacated.
Analytical models are formulated to predict how bus discharge flows from busy, multi-berth stops are affected by allowing buses to freely exit, but not freely enter berths. These models apply when: a bus queue is always present at the stop’s entrance; buses depart the entry queue and enter the stop as per the restriction described above; and the stop is isolated from the effects of nearby traffic signals and other bus stops. We find that for these restricted-entry stops, bus-carrying capacities can often be improved by regulating the exit maneuvers as well. This turns out to be particularly true when the stop’s number of berths is large. Simulations show that these findings still hold when a stop is only moderately busy with entry queues that persist for much, but not all of the time. The simulations also indicate that removing any restrictions on bus exit maneuvers is almost always productive when stops are not busy, such that short entry queues form only on occasion, and only for short periods. We argue why certain simple policies for regulating exit maneuvers would likely enhance bus-stop discharge flows.