No abstract is provided. / Thesis / Master of Engineering (MEngr) / Scope and contents: This thesis describes an analytical study of the dynamics of a tractor-semitrailer vehicle. Two mathematical models; an articulated vehicle with self steering semitrailer and an articulated vehicle with a standard semitrailer, are developed to describe the longitudinal, lateral, vertical, pitching, rolling and yawing motions of the vehicle on a rough road surface. The natural frequencies of and the damped eigenvalues for both models are calculated. The steady state response of the vehicle components to the sinusoidal input profile of varying frequencies is calculated and the response curves are computer plotted in each case. For the self-steering semitrailer, the effect of varying the spring stiffness at the fifth wheel is studied. The dynamic loads imparted to the pavement due to the dynamic action of the vehicle in response to road irregularities, are also calculated. A discussion of the conclusions drawn from the analysis is given.