The chaotic vibration analysis of a heavy articulated vehicle (HAV) under consecutive speed control humps (SCHs) excitation is studied. The vehicle is modeled as a nonlinear half-truck oscillatory system with three axles. The suspension system between the truck bodies and axles is equipped with passive viscous damper and magnetorheological (MR) damper. The consecutive SCHs-speed coupling excitation function is presented by a half-sine wave with constant amplitude and variable frequency. The nonlinear dynamic behavior of the system is investigated by special respective techniques. Also, the ride comfort is assessed by the RMS value of truck bodies' accelerations. The results reveal that the quasi-periodic motion is observed at lower speeds when the truck moves on SCHs without load; while in the presence of the load, the dynamic characteristics of the system confirm the chaotic vibration possibility in a widespread range at higher speeds. Further studies indicate that the chaotic behaviors can directly affect on driving comfort and lead to the ride comfort becoming lower. The obtained results can be helpful in designing the oscillatory system for the heavy vehicles to preserve the comfort of drivers and the protection of load.