Journal of Urban Planning and Development

This paper proposes a framework for using business and organizational scenario-planning techniques for regional strategic transportation-planning purposes. The paper provides a brief history of scenario planning as it emerged from business-strategic planning activities and gives an overview of its goals and limitations. The paper then reviews the context for scenario planning in regional transportation planning as well as precedents of its application in this field. The paper continues with a presentation of a scenario-planning framework for transportation as refined and applied to the Houston metropolitan area. The major findings and lessons from this application are discussed, together with conclusions and observations regarding further potentials and refinements.

Consider a city, with multiple regional activity centers (RACs), in which the locations of traveler demand are continually dispersed. The total demand generated from a particular location in the city is fixed, but the demands from this location to the RACs are subject to a distribution function with respect to the relative transportation cost to each RAC. We take into account the cost of transportation in characterizing travelers’ choices. The congestion effect is explicitly built into the model by using a flow- and location-dependent transportation cost function. The routing behavior of travelers in the city and the user equilibrium choices of RACs are modeled by constructing a spatial user equilibrium flow pattern. The problem is formulated as a combined distribution and assignment model. A solution algorithm that is improvement upon a previously adopted iterative algorithm between the distribution function for the choice of RAC and a mixed finite-element method for route choices is proposed to solve the resultant continuous problem. A numerical example is given to demonstrate the superiority of the improved algorithm.

In this paper we present a new concept for balancing car ownership from both user demand and road network supply conditions. On the demand side, territory-wide and zonal car ownership is first estimated by an aggregate and a disaggregate car ownership models, respectively. A simulated probability distribution of the territory-wide car ownership is also established to assess the reliability of the estimated car ownership. From the road network supply conditions, the maximum number of cars by zone is determined in view of the capacity of the road network and the number of available parking spaces by a bilevel programming model. The proposed bilevel programming model is aimed at examining whether existing road network supply conditions are capable for accommodating future zonal car ownership growth. A case study in a Hong Kong urban area is presented to integrate the results of user demand and network supply conditions to obtain the balance of territory-wide car ownership. The balanced car ownership is found to be the most efficient scenario in terms of total network travel time and utilization of network facilities.

For many freight carriers, uncertainty about travel times (or more generally, about travel costs) is a pervasive aspect of routing and scheduling. As the impact of an unforeseen delay on costs can be substantial, freight carriers will often wish to know which links are critical and what routes and schedules are less risky in cost terms. This paper concentrates on low probability, high consequence incidents whose probabilities are in practice unknown. The dispatcher therefore seeks a risk-averse routing and scheduling strategy. A game theoretic approach developed for transport network reliability is applied to the vehicle routing problem. Underlying this approach is the formulation of a maximin problem, whereby expected cost is minimized with respect to link use frequencies and maximized with respect to failure probabilities. A method of successive averages scheme allows the use of industry standard routing and scheduling software.

Urban sprawl makes conventional transit less competitive and points to the need for more innovative and flexible demand-responsive transit systems in the future. To increase their efficiency, such systems can take advantage of the emerging advanced public transportation systems technologies, e.g., vehicle location and information systems. However, little is known about how consumers might respond to such systems and what they desire. This paper explores the demand for a consumer-oriented Personalized Demand-Responsive Transit (PDRT) service in the San Francisco Bay Area. Such a system could provide services to the traveling public for journeys to work and to nonwork destinations. Results from six focus group meetings and a computer-assisted telephone survey of commuters and noncommuters are reported. While about 60% of those surveyed were willing to consider PDRT as an option, about 12% reported that they were “very likely” to use PDRT $(N=1\text{,}000)\text{.}$ Many were willing to pay for the service and valued highly the flexibility in scheduling the service. Spatial analysis of the survey responses suggests localities where a PDRT may be field-tested.

Growing traffic congestion, the need to preserve the environment, and the problems of road safety are the main reasons for many cities worldwide to consider new initiatives in public transportation (PT) systems. This work discusses the major elements and challenges around and within the introduction of a new or an improved PT system. The choice between public and private transport is an individual decision that is influenced by government/community decisions. These decisions are often sending mixed signals to the public transport passengers and potential users while failing to recognize system-wide and integration implications. This work attempts to provide the current state of the PT practice and to cover the issues of why or why not to use PT including the willingness to pay, viability and projection perspectives, the effectiveness of new initiatives mostly in Europe and North America, and achieving multimodal service integration. In addition a concluding example is provided with reference to the city of Auckland in New Zealand.