In relation to the development of a Rolling Wheel Deflectometer (RWD), which is a non-destructive testing device for measuring pavement deflections, a finite element model for obtaining the soil/pavement response is developed. Absorbing boundary conditions are necessary in order to prevent reflections of the waves propagating through the soil due to the dynamic loading. The Perfectly Matched Layer (PML) has proven to be highly efficient when solving transient wave propagation problems in a fixed mesh. However, since the RWD is operating at traffic speeds, the load is moving with high speed and a formulation in a moving mesh is therefore more convenient. In this paper, a formulation of the PML is developed in the moving frame of reference. Numerical results are presented for a single layer and a double layer half space, respectively, subjected to a moving load of different velocities.