Anthony F. Han

The allocation of buses in heavily utilized networks with overlapping routes

Many transit systems outside North America are characterized by networks with extensively overlapping routes and buses frequently operating at, or close to, capacity. This paper addresses the problem of allocating a fleet of buses between routes in this type of system; a problem that must be solved recurrently by transit planners. A formulation of the problem is developed which recognizes passenger route choice behavior, and seeks to minimize a function of passenger wait time and bus crowding subject to constraints on the number of buses available and the provision of enough capacity on each route to carry all passengers who would select it. An algorithm is developed based on the decomposition of the problem into base allocation and surplus allocation components. The base allocation identifies a feasible solution using an (approx.) minimum number of buses. The surplus allocation is illustrated for the simple objective of minimizing the maximum crowding level on any route. The bus allocation procedure developed in this paper has been applied to part of the Cairo bus system in a completely manual procedure, and is proposed to be the central element of a short-range bus service planning process for that city.

On dynamic demand responsive transport services with degree of dynamism

The operation of a demand responsive transport service usually considers advanced and real-time requests. Previous studies focused on solution algorithms for routing and scheduling challenges of a pickup and delivery problem with time windows, but the operational issues of the overall system performance under a partially dynamic environment have not been investigated. In this article, we explore the operating efficiency of a dispatching system with a degree of dynamism (i.e. a ratio of dynamic requests). It is found that a dispatching system incurs higher transportation costs and accepts fewer requests when the request arrivals are partially dynamic, as compared to static or fully dynamic scenarios. Operational policies are derived for the dispatcher to avoid the inefficient range of degree of dynamism if future demand can be anticipated.

A Gids Metaheuristic Approach to the Fleet Size and Mix Vehicle Routing Problem

This paper presents a new metaheuristic approach, i.e., the GIDS (Generic Intensification and Diversification Search), as well as its performance for solving the FSMVRP (Fleet Size and Mix Vehicle Routing Problem). The GIDS integrates the use of some recently developed generic search methods such as TA (Threshold Accepting) and GDA (Great Deluge Algorithm), and the meta-strategies of intensification and diversification for intelligent search. The GIDS includes three components: (1) MIC, multiple initialization constructor; (2) GSI, generic search for intensification; (3) PSD, perturbation search for diversification. A bank of twenty FSMVRP benchmark instances was tested by several different implementations of GIDS. All programs were coded in UNIX C and implemented on a SPARC 10 SUN workstation. Results are very encouraging. We have updated the best-known solutions for two of the twenty benchmark instances; the average deviation from the twenty best solutions is merely 0.598%.

Residents’ perceptions on the traffic impact of a special event: a case of the Macau Grand Prix

ABSTRACT Special events may cause significant disruptions to the community and affect the daily lives of the local residents. This study examines how local residents perceive the traffic impact of a major tourism event, the Macau Grand Prix, which is an annual event that takes place on a circuit around the streets of the city, Macao. An exploratory factor analysis reveals five factors regarding the traffic impacts of the event, and the residents of different transportation modes have distinct views on the traffic measures. Bus transit and pedestrian traffic management is found to be the most effective. The result provides the event organizer implications and assessment for the traffic planning and management measures in gaining support from the community.