Dynamic Interlining in Bus Operations

TL;DR

This paper explores the concept of dynamic interlining in bus operations, where shared fleets are dispatched on-demand to improve service reliability at hubs, using simulation and case studies to evaluate its effectiveness.

Contribution

It introduces a novel operational strategy for bus routes at hubs, formulates its optimization, and systematically evaluates its impact on service reliability through simulation.

Findings

Dynamic interlining improves on-time departures.

Shared fleet fraction significantly affects performance.

Higher route frequency enhances benefits when all buses are interlined.

Abstract

The paper introduces and evaluates the concept of the dynamic interlining of buses. Dynamic interlining is an operational strategy for routes that have a terminal station at a common hub, that allows a portion of (or all) the fleet to be shared among the routes belonging to the hub (shared fleet) as needed. The shared fleet is dispatched on an on-demand basis to serve scheduled trips on any route to avoid delays and regulate services. The paper examines systematically the impacts of dynamic interlining on service reliability. It formulates the dispatching problem as an optimization problem and uses simulation to evaluate the dynamic interlining strategy under a variety of operating conditions. Using bus routes in Boston Massachusetts Bay Transportation Authority (MBTA) as a case study, the feasibility of the strategy, as well as factors that affect its performance are investigated. Results show that dynamic interlining can improve service reliability (increases on-time departures and decreases departure headways variability at the hub). The fraction of the fleet that is shared has the most dominant impact on performance. In the case where all buses are dynamically interlined, the performance improves as route frequency increases and more routes participate in the strategy.