<p>Passenger search time is an essential variable in a street-hail taxi operation. Fundamentally, the statistical distributions of passenger search time form the basis of analytical and simulation models for describing the taxi system’s dynamics. To create accurate analytical and simulation models that realistically represent the dynamics of the actual taxi system, it is inevitable to characterize the type of statistical distributions that can effectively model the empirical distributions. While the probability distribution functions of passenger search time are critical elements of analytical and simulation models, their empirical distributions under different levels of supply-demand imbalance have not been characterized in any existing studies. In this paper, based on more than eight million real taxi trips in Bangkok, Thailand, and formal statistical analysis, we identify the probability distributions that can effectively model the empirical distributions of passenger search time under different levels of taxi supply-demand imbalance.</p>