Using Discrete-Event Simulation to optimize earthmoving equipment fleet under urban traffic conditions in Vietnam

Abstract

This study applies Discrete-Event Simulation (DES) to evaluate the impacts of urban traffic conditions on schedule and cost performance in earthwork operations and to identify an optimal construction equipment fleet configuration. An initial fleet was first determined using conventional theoretical calculations, consisting of 4 excavators and 8 trucks per excavator to complete the work. The earthwork process was then modeled in EZStrobe and extended through multiple simulation scenarios, in which the probability of stopping at signalized intersections (P1) was treated as the primary influencing variable. Results indicate that under the most unfavorable condition (P1 = 100%), project duration and cost increase by 28.24% and 29.9%, respectively, compared with the theoretical estimate. Under the traffic conditions observed at the project site (P1 = 70%), additional scenarios were analyzed by varying the number of excavators from 4 to 6. The simulation identified the optimal fleet configuration that satisfies both schedule and cost objectives as 6 excavators combined with 8 to 9 trucks per excavator. These findingsconfirm that explicitly accounting for stochastic urban traffic factors is necessary to ensure feasible construction planning, and they demonstrate that DES is an effective decision-support tool for selecting construction execution strategies.