Optimizing Haul Fleet Size Using Queueing Theory

A method, usable by a construction engineer, which will optimize the size of haul fleet in a one-loader operation is presented. The primary innovation is the development of a Poisson ratio that can be computed easily using only a slide rule or a desk calculator. It is presented not as an end result, but as a partial means of bringing more scientific decision-making tools to the construction industry. The method involves a technique, hypothesized by Shaffer of Illinois, of determining the optimum number of trucks that will cause minimum lost time due to the loader standing idle while waiting for a truck. The writer takes the model developed by the above and derives from the complicated distribution obtained, a simple Poisson ratio that could be used by any construction engineer. An explanation of the use of this formula and an example are also presented.