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Title: Motorized and non-motorized transport systems : modeling and optimization
Authors: Wu, Zixiao
Degree: Ph.D.
Issue Date: 2005
Abstract: High-density development in Hong Kong urban areas results in heavy concentrations of people and much conflict between the needs of pedestrians and vehicles, imposing noise and air pollution and threatening the lives of pedestrians. There is a need to alleviate these adverse effects by encouraging multi-modal transport and improving facilities for both motorized (i.e. road and transit) and non-motorized (i.e. pedestrian) modes in congested urban areas. In order to do so at the strategic planning stage, it is necessary to develop methods for assessing the impacts of multi-modal transport management policies (e.g. pedestrian-only streets, high-occupancy vehicle lanes or various transport pricing strategies) in congested transport networks with multiple modes of travel that include walking, auto, multiple transit modes and combined modes (such as park-and-ride or taxi-transit). This research appears to be the first devoted exclusively to the topic of advanced modeling for a multi-modal transport system with the integration of motorized and non-motorized transport modes. The first contribution of this thesis is that an alternative approach is proposed to modeling the multi-modal transport networks with combined-mode trips. Multi-modal network equilibrium is based on a multi-layer network framework that can facilitate the generation of feasible (or viable) routes in a multi-modal transport network according to the features of the used modes along the routes. The proposed approach may capture travelers' perceptive variations on alternative routes as well as on used modes along the routes, and determine inter-related travel choices (i.e. combined-mode demands and route flows) simultaneously. The incorporation of non-motorized travel-the walking mode info the modeling system is the second contribution of this thesis. The bi-directional pedestrian flow effects on two-way walkways are taken account in the travel choice process. Travelers may walk directly from origins to their destinations or use both the walking and motorized modes for their whole journeys. Walking components involved in the access and egress of motorized modes are treated in the same manner as the pure walking trips. As a result, a motorized trip is associated with a flow-dependent walking time. This differs from the conventional approach, in which walking time is fixed and independent of pedestrian flows. The new approach is more realistic in congested urban areas such as that in Hong Kong. The third contribution of this thesis is the treatment of the selection of pedestrianisation (pedestrian-only Street) locations as a discrete multi-modal network design problem. A bi-level model is proposed to determine the optimal pedestrianisation locations. Modal equity constraints are imposed to balance the benefits to users of various transport modes, under a pedestrianisation scheme. A case study is carried out in a selected area on Hong Kong Island to show the applicability of the proposed bi-level model and the solution algorithm for multi-modal transport networks in real world. The fourth contribution of this thesis is to estimate the person trip origin-destination matrix, using a partial set of updated link count information in multi-modal transport networks. This study extends the literature on origin-destination matrix estimation by: (i) allowing for combined-mode choice as well as route choice, and (ii) taking interactions between various transport modes into account in the origin-destination estimation process. A bi-level model, together with an adapted solution algorithm, is proposed to obtain the updated person trip origin-destination matrix and a solution to the multi-modal network equilibrium problem, simultaneously. The fifth contribution of this thesis is the formalization of two multi-modal transport management policy problems, namely the optimal design of high-occupancy vehicle lanes, and the optimal transport pricing strategies. These two policies aim at motorized modes and thus the multi-modal network design problems associated with them are viewed as two extensions of this research. To evaluate the high-occupancy vehicle lane use, the carpooling option is incorporated in the multi-modal network equilibrium problem, leading to a thee-level nested logit model to account for the complex and inter-related travel choices in the multi-modal setting. With the multi-modal network equilibrium problem at the lower level, a bi-level model is used to determine the optimal design of high-occupancy vehicle lanes. The optimal transport pricing strategies are investigated using a simplified bi-modal transport network with two user groups. By expressing the stochastic user equilibrium conditions as a group of equations, single-level optimization problems are proposed for various transport pricing strategies. Analytical solutions can be derived from the optimality conditions. In addition, equity issues are also addressed in the above two transport management policies.
Subjects: Hong Kong Polytechnic University -- Dissertations
Transportation -- Mathematical models
Transport theory -- Mathematical models
Pages: 1 v. (various pagings) : ill. ; 30 cm
Appears in Collections:Thesis

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