A constrained interactance model for trip distribution

A constrained interactance model for trip distribution

Author: Gary D. Long

Publisher:

Published: 1973

Total Pages: 570

ISBN-13:

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To estimate the future volume of trips interchanging between each pair of zones within an urban area, a simple behavioral model of travel interaction is presented. The interactance model is subjected to a set of five constraints, which reflect pertinent conditions that should be fulfilled in the resulting distribution. A method is developed to distribute future trips in accordance with the interactance model so that all constraints will be satisfied. The constrained interactance model differs from other trip distribution models in that the distribution of trip lengths is constrained to result as given in advance. Furthermore, no model calibration is necessary. Rather than the conventional use of subjective judgements to distinguish the travel movements which warrant exogenous compensations to correct for socioeconomic biases, an objective procedure utilizing a statistical test is provided. Socioeconomic and geographic compensations, where needed, are applied between pairs of groups of contiguous and homogeneous zones rather than between individual zone pairs. A model is developed to determine the total number of zone pairs expected to have travel interactions in an urban area, as a function of the number of trips and zones. Another model which describes travel interaction propensities as related to travel disutility, is developed to indicate which pairs of zones are the least likely to have travel interactions, and should be dropped from the trip distribution, in order to restrict the number of travel interactions to the estimated total. ...


Travel Forecasting Guidelines

Travel Forecasting Guidelines

Author:

Publisher:

Published: 1994

Total Pages: 316

ISBN-13:

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Implementing transportation improvements requires a significant effort that may involve several levels of planning; social, economic and environmental documentation; geometric and structural design; operations analysis; signalized intersection design; and/or pavement design. Accurate and timely traffic estimates and forecasts are basic to the entire transportation planning process and are essential to enable the Texas Department of Transportation (TxDOT) to effectively meet the mobility needs of the state. This guide provides an introduction to the transportation planning and travel demand forecasting requirements and establishes the policies, processes and methodologies for developing traffic forecasts for the various stages of TxDOT project development.


Summary Documentation for the Texas Travel Demand Package

Summary Documentation for the Texas Travel Demand Package

Author: Thomas A. Williams

Publisher:

Published: 1992

Total Pages: 64

ISBN-13:

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The statewide practice of urban travel forecasting in Texas is described. An overview of methods practiced and theoretical basis for travel modeling is presented in brief format. Each of the four steps used in the Texas Package travel modeling process is described. TRIPCAL5, the Texas Package trip generation method, is summarized. Trip distribution practice using the Texas Package ATOM model is included. Finally, the Texas Package methodology using the iterative traffic assignment process is described.