Abstract: A ballast system for use in a cargo bed of a vehicle, such as a pick-up truck, provides generally even weight distribution over rear or powered wheels of the vehicle. The ballast system provides additional weight to the cargo bed of the vehicle, thereby improving stability, handling, and rear wheel traction, especially during inclement weather, such as in snow or rain. The ballast system may be rolled-up into a compact roll during non-use for convenient storage. The ballast system has a plurality of weighted cross-members laminated, attached, or bonded between two generally pliable mats. The cross-members are, preferably, equally spaced apart from each other along widths of the mats and transverse to a longitudinal direction of the cargo bed of the vehicle. The ballast system is readily rolled-up into a compact roll for convenient storage.