Increasing the speed of motor-tractor trains (ATP) with trailers is associated with a rather complex problem of improving traffic safety in operating conditions. With an increase in the speed of the ATP movement on straight paths, the span of transverse horizontal deviations (swerves) of trailer links may arise and grow along with the speed. Side deviations increase the width of the overall corridor and the traffic lane of the ATP, increase the risk of skidding of the trailer and its departure from the designated lane, make it difficult to control the vehicle. At certain speeds, the extent of these deviations can be so large that it can create an emergency on public roads and cause catastrophic consequences. Transverse vibrations of trailer links in the horizontal plane can occur when the tractor is moving in a strictly straight line at speeds exceeding 40-45 km/h.The paper presents the results of theoretical studies of the stability of the movement of motor-tractor trains. Factors affecting the critical speed of a two-axle trailer beyond which the movement of a road train may not be stable are determined. Technical solutions for the modernization of traction devices that improve the stabilization of the links of the tractor train are proposed. Some results of experiments on large-scale models of motor-tractor trains to study the influence of stabilizing traction devices on the stability of their movement are presented.