Optimum fleet size determination by queuing and simulation

Queuing theory applications in the field of earth-moving operations are reviewed. Using queuing theory and simulation techniques, a model is developed that can predict the productivity of one pusher and a fleet of scrapers under a given set of operating conditions. A computer program is developed for this purpose that interfaces Gaarslev's Queuing Model Program and Caterpillar's Vehicle Simulation Program. The new system can consider the effect of variable inter-arrival times and bunching and road and machine conditions. The developed computer system allows the user to perform a sensitivity analysis by varying the number of scrapers, thus determining the optimum fleet size based on the lowest cost per cubic yard of production.