The application of the Poisson distribution to traffic problems is reviewed. Appendices present the derivation of the Poisson distribution starting from the fundamental concepts of permutations and combinations. The nature of Poisson distribution is discussed. Examples are given of Poisson distributions. In the examples presented it was postulated that a Poisson distribution having a certain parameter whose value has been computed from the observed data describes the population that has been sampled. The chi square test is used as a statistical test of significance to check the inference that the postulated theoretical (Poisson) distribution is in fact the true population distribution. The technique of performing the chi square significance test is illustrated. The following traffic applications of the Poisson distribution are derived: (1) analysis of arrival rates at a given point, (2) studies of vehicle spacing (gaps), (3) determination of the probability of finding a vacant parking space, (4) studies of certain accidents, and (5) design of left-turn pockets. Examples are given of the use of the cumulative and multiple Poisson distribution. The procedure is reviewed for computing probabilities from the Poisson distribution.
Samenvatting