Book Description

The origin-destination (O-D) trip table is a key input required for traffic assignment and simulation models utilized to analyze a wide variety of transportation applications. The main goal of this research is to develop an economical and quick method for estimating O-D trip tables from traffic counts. Path flow estimator (PFE), originally developed by Bell and Shield (1995), has been further developed to improve the reliability and efficiency of O-D trip table estimates. The research reported herein includes only the development of the steady-state O-D estimator. In this study, the original PFE model was carefully examined in several aspects to gain more insight for further improvements. Currently, the PFE has been successfully applied to estimate the steady-state O-D trip tables for the Irvine Testbed network in Orange County, California as well as some other real networks. The primary results demonstrate that PFE has the capability to correctly estimate the total and individual O-D demands when proper information is provided. They also indicate that the number and locations of traffic counts significantly influence the quality of O-D estimates as each observation contributes different amount and quality of information. The most difficult task observed thus far is the estimation of spatial pattern of O-D demands even when traffic counts were collected on all network links. These issues and the development of time-dependent PFE will be investigated in the second phase under Task Order 5502