Browsing by Subject "UTPS"
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Item An Evolutionary Transportation Planning Model: Structure and Application(Transportation Research Board, 1995) Levinson, David MThis paper describes an evolutionary transportation planning model wherein the demand in a given year depends on the demand of the previous year. The model redistributes a fraction of the work trips each year due to the relocation of a household or taking a new job, while changes in distribution due to growth (or decline) are considered. This hybrid-evolutionary model is compared with an equilibrium model, wherein supply and demand are solved simultaneously. The reasons for preferring the evolutionary method to the equilibrium approach are several: (a) the ability to more easily use observed data and thereby limit modeling to changes in behavior; (b) additional realism in the concept of the model; (c) the provision of a framework for extension to integration with land use models; and (d) the additional information available to policy makers.Item Integrating Feedback into the Transportation Planning Model(Transportation Research Board, 1994) Levinson, David MThis research develops and applies a new structure for the transportation planning model that includes feedback between demand, assignment, and traffic control. New methods, combined with a renewed interest in transportation planning models prompted by the Clean Air Act of 1990 and the Intermodal Surface Transportation Efficiency Act of 1991, warrant a reconsideration of the traditional "four-step" transportation planning model. This paper presents an algorithm for feedback which results in consistent travel times as input to travel demand and output from route assignment. The model, including six stages of Trip Generation, Destination Choice, Mode Choice, Departure Time Choice, Route Assignment and Intersection Control is briefly outlined. This is followed by an application comparing a base year 1990 application with a forecast year of 2010. The 2010 forecast is solved both with and without feedback for comparison purposes. Incorporation of feedback gives significantly different results than the standard model.