Emerging Techniques for Urban Transportation Planning

Abstract

Despite several decades of intense effort, urban transportation planning is in its infancy of development and refinement, as evidenced by the fast pace of new techniques and methodologies being proposed and developed. In this series of two special issues on urban transportation planning, the first issue @Journal of Urban Planning and Development, 128~4!, 2002# focused on reviews of recent methodological advances. This second issue covers emerging techniques that extend the boundries beyond the traditional four-step planning methodology. Some of these techniques are drawn from other fields of studies. Others introduce new dimensions to reconsider the problem. All in all, these approaches open up new possibilities and dimensions as well as make planning procedures more robust, thereby enabling the planning results to be applicable to a wider range of scenarios and for the longerterm future. Six papers are contained in this special issue. Drawing from business and organizational scenario planning techniques, the paper by Zegras, Sussman, and Conklin, ‘‘Scenario Planning for Strategic Regional Transportation Planning,’’ proposes a scenarioplanning framework for regional transportation planning. The study reviews the context of scenario planning for regional transportation planning, illustrates the approach through application to the Houston, Texas, metropolitan area, and concludes with findings, lessons learned, and future potentials and refinements of the approach. To improve the analysis of multicommodity demand and traffic patterns of a city with multiple regional activity centers, the paper by Wong, Zhou, Lo, and Yang, ‘‘Improved Solution Algorithm for the Multicommodity Continuous Distribution and Assignment Model’’ develops a new combined distribution and assignment model. A unique feature of this approach is that the dispersion of demand is modeled as a continuous function over space, in contrast to the traditional approach where demands are lumped at origin nodes or centroids. The study then proposes an efficient algorithm to solve the formulation. In the third paper, ‘‘Balance of Car Ownership under User Demand and Road Network Supply Conditions—Case Study in Hong Kong,’’ Tam and Lam propose a new concept for estimating car ownership. It considers the interactions between user demands and road network supply conditions, thereby factoring in the congestion effect to the estimation of car ownership on top of the traditional socioeconomic characteristics of the population. The paper then illustrates the approach through a case study in Hong Kong. Understanding users’ routing strategies is important, as it will lead to the design of more robust transportation networks. The paper by Bell, ‘‘Games, Heuristics, and Risk Averseness in Vehicle Routing Problems,’’ develops an approach for vehicle routing in networks with uncertain travel times. The study focuses on the case of freight carriers, wherein the dispatcher seeks a riskaverse routing and scheduling strategy. The writer formulates the problem with a game theoretic approach and solves it with a method of successive averages scheme. For low-density urban developments that render conventional transit services less competitive or cost-effective, perhaps only demand-responsive transit services are viable, if any at all. The paper by Khattak and Yim, ‘‘Traveler Response to Innovative Personalized Demand-Responsive Transit in the San Francisco Bay Area,’’ investigates the market for Personalized Demand Responsive Transit ~PDRT!. The study attempts to understand travelers’ willingness to use and pay for PDRT based on focus group meetings and a computer-assisted telephone survey. Such results are indicative for the planning of demand-responsive transit services. Finally, the paper by Ceder, ‘‘New Urban Public Transportation Systems: Initiatives, Effectiveness, and Challenges,’’ examines the major elements and challenges for the introduction of a new or an improved public transportation system. Drawing upon experiences in Europe and North America, the paper reviews the current state of practice and covers issues related to the use of public transportation services. The paper concludes by illustrating the case of the city of Auckland, New Zealand. These papers illustrate the range of research directions to improve the urban transportation planning process. Some focus on the methodological framework, others on broader and more connected considerations, better understanding of travelers’ choices, and issues that ought to be carefully considered in new initiatives or improvement schemes. We trust that, collectively, these two special issues serve to broaden the perspective on the new approaches for urban transportation planning. It is our hope that they will inspire and stimulate new research initiatives and efforts in this still evolving field.