The paper briefly presents two simulation models which describe the motion and dynamics of biaxial vehicles: a medium class car and 12 tons truck. The road surface may be even or uneven. The main models may be divided into coupled submodels. Their equations of motion can be derived separately. The programs can be run even on personal computers. The models are experimentally verified on even roads for typical manoeuvres recommended by ISO. The paper shows mainly the results of experimental evaluation of simulation models. It also presents steering system submodel in more detail. Its combination with other submodels describe small car motion and dynamics including the influence of steering system freeplay and dry friction.