The slosh forces arising due to liquid motion in partially filled containers affect the roll dynamic stability of tank vehicles. In this paper, a simplified dynamic truck roll model has been developed considering both suspension flexibility and nonlinear dynamics of the liquid cargo motion. A small-scale experimental model for a cylindrical truck tank, excited in the lateral direction, is designed and constructed to measure the viscous damping and damped natural frequency of the liquid cargo. Since the viscous damping of the liquids is limited by its natural characteristics, partitions containing rectangular slots and holes of different sizes are used to generate additional damping. It is fitted against the lateral motion of the liquid slosh, i.e. parallel to and passing through the longitudinal axis of the vehicle. These types of partitions increase the motion damping of the liquid cargo and make the liquid behave like a dynamic absorber. A similarity technique is developed to make the measured data applicable for the full size vehicle. The experimentally measured parameters of the slosh motion are used to calculate the roll responses of the vehicle. The results showed that, significant reduction in the vehicle body roll motion and the shift of the cargo center of gravity are achieved due to the additional damping potential of the designed anti-slosh damper. Finally, recommendations for further work are given.