An Evaluation of the Oahu Transportation Study Land Use Model

Abstract

The Oahu Transportation Study (OTS) Land Use Model occupies a central role in transportation planning for the island of Oahu. Developed by Ronald Graybeal of the Center for Real Estate & Urban Economics, University of California, Berkeley, it has been used extensively since its completion in 1967 - from the initial Oahu Transportation Study to the recent Preliminary Engineering Evaluation Program (PEEP) of Honolulu's rapid transit project. Yet, the crucial question of whether or not the model works has never been answered. The model has never been validated. Although the process of validation is necessarily constrained by the availability of actual data to which the model can be checked, it was perhaps the attitude of acceptance in the model as a "black box" that was most responsible for the failure to even attempt validation of the model. This attitude is directly attributable to the lack of documentation of the model. Graybeal authored the only written description of the land use model in its entirety. In it he discussed the basic concept of the model and outlined the equation system of each of the model's submodels: Hotel, Residential, Commercial and Public/Industrial. However, as neither the functional form nor the coefficients of some of the equations are specified, it is at best an overview.