Vehicles pass their loads through tires onto pavements. Traditionally, the vertical contact pressure is assumed to uniformly distribute in a rectangle or circular area, whereas the shear contact pressure is ignored in pavement design. Experiments have demonstrated that the interaction between the tire and the pavement surface is very complicated. The contact area is not a regular shape and the distribution of contact pressure is not uniform. However, experimental approaches to measure contact pressure are usually time and energy consuming, whereas the results are subject to errors introduced by measurement sensors. On the other hand, numerical simulation can describe the interaction between tire and pavement surface under all circumstances, such as various driving conditions, different tread types, and so on. In this paper, a three-dimensional finite-element model for tires was developed. The model was validated by the static test data. Then the interactions of different tires with pavement were analyzed, including the vertical and shear contact-pressure distributions on tires and on pavement surfaces. The influences of pavement friction and load level on the contact-pressure distributions of tires and pavement were investigated as well. It was found that vertical and shear contact pressures on tires and pavement were quite different when the type of tire or the friction changed. The contact-pressure distribution was found not uniform and the shape of contact area changed as the load level varied. The complicated interactions between different tires and pavement indicate that sophisticated tire models are necessary to obtain more accurate pavement responses.