Abstract:This paper introduces a specific method to update shortterm trip generation rate applicable in Chinese cities on the basis of theoretical analysis of Bayesian statistical methodology and previous method of updating parameters related to transportation analysis.According to this method, the historic trip investigation data are assumed to be the prior information and prior distribution,a limited number of recent cases are taken as new sample, and the shortterm trip generation rate taken as posterior probability to be predited. If the number of historic and new samples are both more than 30,and their mean and standard deviation are assurned to be the unbiased estimator of the prior and sample variance,the expectancy of posterior distribution, viz. the shortterm trip generation rate,can be calculated using Bayesian statistical methodology.The feasibility of this method is exemplified and its deficiency and suitability are also pointed out.