Traffic distribution fitting : a systematic methodology.

Traffic distributions are an integral part of many traffic analyses. The correct determination of these distributions is therefore essential. This paper presents a methodology for the determination of the appropriate distribution. The methodology incorporates the data investigation, model selection, parameter estimation, and goodness-of-fit stages in distributions fitting. Many traffic analysts pay scant attention to the first two steps. The methodology is formulated within a microcomputer program, TRANSTAT, that has been developed to determine appropriate traffic distributions. TRANSTAT incorporates many recent developments in exploratory data analyses, expert systems, and outlier analyses. The paper describes the program and illustrates its application to the determination of parking duration curves.