We report a Boltzmann analysis of transport measurements performed on quasi two-dimensional (2D) electron gases with strong in-plane periodic modulation at a short length scale. The quantum scattering anisotropy induced by the periodic potential is included in the calculation and is shown to play an important role in the low-temperature electrical anisotropy. Furthermore, under these conditions the conductivity along the unperturbed direction is no longer given by the Drude formula but is enhanced because of a strong inhibition of the relaxation rate.