ESTIMATION OF O-D FLOWS FROM TRAFFIC COUNT AND LICENSE-PLATE SURVEY INFORMATION

The design of traffic management schemes usually requires knowledge of the pattern of trips on the system under scrutiny. This pattern is ordinarily described by an o-d flow matrix. One of the common tasks of this type is the estimation of flows between the intersection approaches on a stretch of road. Estimation is based on intersection flow counts which are supplemented by a sample license-plate survey. In this paper a procedure is developed to obtain the most likely o-d flow estimates using both intersection counts and results of the sample license-plate survey. This procedure ensures that best use is made of available data. The procedure is illustrated in detail on the basis of a numerical example. An earlier paper reported a method of estimation which relies on intersection counts only and does not require the conduct of a sample license-plate survey. It is therefore important to examine how the estimation accuracy increases when the added information from the license-plate survey is used and in particular, how accuracy increases with sample size. This is done on the basis of empirical data for a road section in Toronto. (Author/TRRL)