FWD is one of the nondestructive test equipment commonly used for evaluating pavement structural adequacy, and it is usually combined with some backcalculation method of pavement layer moduli. The calculated moduli are affected by the type of the analyzing model as well as the accuracy of the measurement.
This paper places an emphasis on determining the optimal position of each deflection sensor of FWD. The simulation was performed using Genetic Algorithms that is a powerful method for obtaining the optimal value among the huge number of combinations. It is found that determination of measuring positions of pavement deflections affects the estimated layer moduli significantly, and a careful selection of adequate measuring positions from the loading point is strongly recommended.