The increased use of recycled and marginal pavement materials is a key factor for more sustainable use of resources. However, successful use of alternative materials requires reliable models of pavement response and performance and in turn, these models depend on the accurate portrayal of tire/road contact stress distributions. Unfortunately, while the models have been developed substantially, the acquisition of real stress distributions measured at full scale has not kept pace. To solve the problem, an apparatus to measure tire/road surface contact stress distributions in all three coordinate directions was fabricated and calibrated. Next, a wide range of full-scale trafficking tests was carried out on the apparatus and the contact stress distributions measured. Those distributions were then input to numerical models of pavement behaviour and the results compared to the results of those models’ predictions for the case where the loading was a uniformly distributed vertical pressure only, within the contact patch. The numerical models are described briefly, comparisons are made between using the measured contact stress distributions and the simple uniform pressure, and conclusions are drawn, including the implications for predicted pavement life.